THE LONG-TERM STRATEGY
OF THE UNITED STATES
Pathways to Net-Zero Greenhouse Gas Emissions by 2050
NOVEMBER
The Long-Term Strategy of the United States: Pathways
to Net-Zero Greenhouse Gas Emissions by 2050.
Published by the United States Department of State
and the United States Executive Oce of the President,
Washington DC. November 2021.
CONTENTS
01 Preface
03 Executive Summary
10 Chapter 1:
An Integrated U.S. Climate Strategy
to Reach Net-Zero Emissions by 2050
13 Chapter 2:
The Decisive Decade to 2030
17 Chapter 3:
Pathways to 2050 Net-Zero
Emissions in the United States
25 Chapter 4:
Transforming the Energy System
Through 2050
35 Chapter 5:
Reducing Non-CO
2
Emissions
Through 2050
45 Chapter 6:
Removing Carbon Through 2050
and Beyond
50 Chapter 7:
Benefits of Climate Action
Through 2050
55 Chapter 8:
Accelerating Global Climate Progress
57 References
THE LONG-TERM STRATEGY OF THE UNITED STATES
In the United States and around the world, we are
already feeling the impacts of a changing climate.
Here at home, in 2021 alone we have seen historic
droughts and wildfires in the West, unprecedented
storms and flooding in the Southeast, and record
heatwaves across the country. We see the same
devastating evidence around the world in places like
the fire-ravaged Amazon, the sweltering urban center
of Delhi, and the shrinking coastlines of island nations
like Tuvalu. The science is clear: we are headed toward
climate disaster unless we achieve net-zero global
emissions by midcentury. We also know this crisis
presents vast opportunities to build a better economy,
create millions of good-paying jobs, clean our waters
and air, and ensure all Americans can live healthier,
safer, stronger lives.
The time is now for decisive action, and the United
States is boldly tackling the climate challenge. In 2021,
we rejoined the Paris Agreement, set an ambitious
Nationally Determined Contribution to reduce net
greenhouse gas emissions by 50-52% in 2030,
launched the Global Methane Pledge, and have
undertaken additional concrete actions to advance
climate action domestically and internationally.
These investments are critical to immediately
accelerate our emissions reductions.
This 2021 Long-Term Strategy represents the next
step: it lays out how the United States can reach its
ultimate goal of net-zero emissions no later than 2050.
Achieving net-zero emissions is how we—and our
fellow nations around the globe—will keep a 1.5°C limit
on global temperature rise within reach and prevent
unacceptable climate change impacts and risks.
The Long-Term Strategy shows that reaching net-
zero no later than 2050 will require actions spanning
every sector of the economy. There are many potential
pathways to get there, and all path-ways start with
delivering on our 2030 Nationally Determined
Contribution. This will put the United States firmly
on track to reach net-zero by 2050 and support the
overarching vision of building a more sustainable,
resilient, and equitable economy.
The benefits of a net-zero future will not only be felt
by future generations. Mobilizing to achieve net-zero
will also deliver strong net benefits for all Americans
starting today. Driving down greenhouse gases will
PREFACE
1
THE LONG-TERM STRATEGY OF THE UNITED STATES
2
THE LONG-TERM STRATEGY OF THE UNITED STATES
create high-quality jobs, improve public health
in every community, and spur investments that
modernize the American economy while reducing
costs and risks from climate change. Reducing air
pollution through clean energy will alone help avoid
300,000 premature deaths in the United States—
alleviating these and other severe impacts that also
fall disproportionately on communities of color and
low-income communities. Investments in emerging
clean industries will enhance our competitiveness and
propel sustained economic growth.
Modernizing the American economy to achieve
net-zero can fundamentally improve the way we
live, creating more connected, more accessible,
and healthier communities. That does not mean it
will happen quickly or without hard work. There will
be many challenges on our path to net-zero that will
require us to marshal all our ingenuity and dedication.
But it can, and must, be done. And even as we invest at
home, the new technologies and investments outlined
in this strategy will also help scale up low-cost, carbon-
free solutions for the world.
We can create a healthy, vibrant, and abundant world
for our children. This plan is our promise to them—and
it is one we must keep.
JOHN KERRY
SPECIAL PRESIDENTIAL
ENVOY FOR CLIMATE
GINA MCCARTHY
NATIONAL CLIMATE ADVISOR
3
THE LONG-TERM STRATEGY OF THE UNITED STATES
Addressing the climate crisis requires immediate
and sustained investment to eliminate net global
greenhouse gas emissions by mid-century—and
this presents a transformational opportunity for the
United States and the world. Investing in the clean
technologies, infrastructure, workforce, and systems
of the future creates an unprecedented opportunity to
improve quality of life and create vibrant, sustainable,
resilient, and equitable economies.
As we undertake this global transformation, the United
States and other major economies must act quickly to
keep a safer climate within reach. Across the United
States and around the world, climate change is already
harming communities—particularly the most vulnerable
that are least equipped to cope, rebuild, and adapt.
Wildfires, storms, floods, extreme heat, and other
climate-fueled impacts are causing deaths, injuries,
degraded health, economic hardship, and damage
to the earth’s ecosystems—all from warming of only
roughly 1.0
o
C. Failure to immediately curtail emissions
will condemn the world to nearly triple that level of
warming, unleashing far more frequent and severe
climate impacts and far more extreme downside risks.
The most recent report from the Intergovernmental
Panel on Climate Change (IPCC) vividly illustrates,
with robust scientific confidence, the need to limit
warming to 1.5
o
C, or as close as possible to that crucial
benchmark, to avoid these severe climate impacts.
Achieving this target will require cutting global
greenhouse gas (GHG) emissions by at least 40%
below 1990 levels by 2030, reaching global net-zero
GHG emissions by 2050 or soon after, and moving to
net negative emissions thereafter [1]. To meet these
global milestones, we must retool the global energy
economy, transform agricultural systems, halt and
reverse deforestation, and decisively address non-
carbon dioxide emissions—focusing particular attention
on methane (CH
4
), which accounts roughly 0.5
o
C of the
current observed net warming of 1.0
o
C.
1
We must also
pursue negative emissions through robust and verifiable
nature-based and technological carbon dioxide removal.
IN LIGHT OF THIS URGENCY, THE UNITED STATES
HAS SET A GOAL OF NET-ZERO GREENHOUSE GAS
EMISSIONS BY NO LATER THAN 2050.
1
Greenhouse gas emissions in total have contributed 150% of the
observed warming of 1.0⁰C, but emissions of cooling aerosols have
counteracted some of that warming.
EXECUTIVE
SUMMARY
4
THE LONG-TERM STRATEGY OF THE UNITED STATES
THIS U.S. NET-ZERO 2050 GOAL IS AMBITIOUS.
It puts the United States ahead of the trajectory
required to keep 1.5°C within reach through three
decades of investment in clean power, electrification of
transportation and buildings, industrial transformation,
reductions in methane and other potent non-carbon
dioxide climate pollutants, and bolstering of our natural
and working lands.
DELIVERING ON OUR 2030 NATIONALLY
DETERMINED CONTRIBUTION (NDC) WILL PUT THE
UNITED STATES FIRMLY ON TRACK TO NET-ZERO.
The United States has committed to an ambitious and
achievable goal to reduce net GHG emissions 50-52%
below 2005 levels in 2030.
2
This is the decisive decade
to deliver on a set of new policies [2] to accelerate
existing emissions reduction trends—for example,
expanding rapidly the deployment of new technologies
like electric vehicles and heat pumps, and building the
infrastructure for key systems like our national power
grid. These types of near-term actions will put us on
firm footing to meet our 2050 goal (as illustrated by
Figure ES-1).
2
The United States formally communicated this 2030 target in its
Nationally Determined Contribution on April 21, 2021.
Figure ES-1: United States historic emissions and projected emissions under the 2050 goal for
net-zero. This figure shows the historical trajectory of U.S. net GHG emissions from 1990 to 2019,
the projected pathway to the 2030 NDC of 50-52% below 2005 levels, and the 2050 net-zero
goal. The United States has also set a goal for 100% clean electricity in 2035; that goal is not an
economy-wide emissions goal so does not appear in this figure, but it will be critical to support
decarbonization in the electricity sector, which will in turn help the U.S. reach its 2030 and 2050
goals in combination with broad electrification of end uses.
17% BELOW 2005
LEVELS IN 2020
26-28% BELOW 2005
LEVELS IN 2025
50-52% BELOW 2005
LEVELS IN 2030
Net-Zero
IN 2050
0
1
2
3
4
5
6
7
0%
-10%
-20%
-30%
-40%
-50%
-60%
-70%
-80%
-90%
-100%
1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050
Emissions (Gigatons CO
2
e)
Percent Below 2005
HISTORIC EMISSIONS
17% BELOW 2005 LEVELS IN 2020
U.S. PROJECTED EMISSIONS UNDER 2025 TARGET
U.S. PROJECTED EMISSIONS UNDER 2030 TARGET
U.S. PROJECTED EMISSIONS UNDER 2050 GOAL
5
THE LONG-TERM STRATEGY OF THE UNITED STATES
THIS REPORT PRESENTS THE 2021 LONG-TERM
STRATEGY (LTS) OF THE UNITED STATES.
It illustrates multiple pathways to a net-zero economy
no later than 2050 [3] [4] [5]. It confirms how actions
taken now and through this decade are critical to make
these net-zero pathways possible. The report draws
from a diverse analytical toolkit,
3
including a global
integrated assessment model covering all GHGs and
economic sectors, a national carbon dioxide (CO
2
)
model with high energy sector resolution, models of
the U.S. land sector, and a rich set of non-governmental
literature. Pursuant to Article 4.19 of the Paris
Agreement, this report also serves to communicate our
Long-Term Strategy to the international community.
MOBILIZING TO ACHIEVE NET-ZERO WILL DELIVER
STRONG NET BENEFITS FOR ALL AMERICANS.
Driving down GHGs will spur investments that
modernize the American economy, address the
distributional inequities of environmental pollution and
climate vulnerability, improve public health in every
community, and reduce the severe costs and risks from
climate change. Benefits include:
• PUBLIC HEALTH. Reducing air pollution through clean
energy will avoid 85,000–300,000 premature
deaths, and health and climate damages of $150–
$250 billion through 2030. It will avoid $1–3 trillion
in damages through 2050 in the United States
alone. These measures will also help alleviate the
pollution burdens disproportionately borne by
communities of color, low-income communities,
and indigenous communities.
• ECONOMIC GROWTH. Investments in nascent clean
industries will enhance competitiveness and propel
sustained growth. The United States can lead in
crucial clean technologies like batteries, electric
vehicles, and heat pumps, without sacrificing
critical worker protections.
3
The core analyses presented in this report are shared with the U.S.
National Climate Strategy and the U.S. National Communication and
Biennial Report to the UN Framework Convention on Climate Change
(UNFCCC).
• REDUCED CONFLICT. Drought, floods, and other
disasters fueled by climate change have caused
large-scale displacements and conflict. The
U.S. Department of Defense recognizes climate
change as a vital, globally destabilizing national
security threat [6]. Early action by the United
States will encourage faster climate action globally,
including by driving down the costs of carbon-free
technologies. These actions will ultimately support
security and stability worldwide.
• QUALITY OF LIFE. Modernizing the American
economy to achieve net-zero can fundamentally
improve the way we live. Measures like high-speed
rail and transit-oriented development not only
reduce emissions but also create more connected,
accessible, and healthier communities.
THE 2050 NET-ZERO EMISSIONS GOAL IS ACHIEVABLE.
The United States can deliver net-zero emissions across
all sectors and GHGs through multiple pathways,
but all viable routes to net-zero involve five key
transformations:
1. DECARBONIZE ELECTRICITY. Electricity delivers
diverse services to all sectors of the American
economy. The transition to a clean electricity
system has been accelerating in recent years—
driven by plummeting costs for solar and wind
technologies, federal and subnational policies,
and consumer demand. Building on this success,
the United States has set a goal of 100% clean
electricity by 2035, a crucial foundation for net-zero
emissions no later than 2050.
2. ELECTRIFY END USES AND SWITCH TO OTHER CLEAN
FUELS. We can aordably and eciently electrify
most of the economy, from cars to buildings and
industrial processes. In areas where electrification
presents technology challenges—for instance
aviation, shipping, and some industrial processes—
we can prioritize clean fuels like carbon-free
hydrogen and sustainable biofuels.
6
THE LONG-TERM STRATEGY OF THE UNITED STATES
3. CUT ENERGY WASTE. Moving to cleaner sources of
energy is made faster, cheaper, and easier when
existing and new technologies use less energy to
provide the same or better service. This can be
achieved through diverse, proven approaches,
ranging from more ecient appliances and the
integration of eciency into new and existing
buildings, to sustainable manufacturing processes.
4. REDUCE METHANE AND OTHER NON-CO
2
EMISSIONS. Non-CO
2
gases such as methane,
hydrofluorocarbons (HFCs), nitrous oxide (N
2
O),
and others, contribute significantly to warming—
with methane alone contributing fully half of
current net global warming of 1.0°C. There are
many profitable or low-cost options to reduce
non-CO
2
sources, such as implementing methane
leak detection and repair for oil and gas systems
and shifting from HFCs to climate-friendly working
fluids in cooling equipment. The U.S. is committed
to taking comprehensive and immediate actions
to reduce methane domestically. And through the
Global Methane Pledge, the U.S. and partners seek
to reduce global methane emissions by at least
30% by 2030, which would eliminate over 0.2°C
of warming by 2050. The U.S. will also prioritize
research and development to unlock the innovation
needed for deep emissions reductions beyond
currently available technologies.
5. SCALE UP CO
2
REMOVAL. In the three decades to
2050, our emissions from energy production can
be brought close to zero, but certain emissions
such as non-CO
2
from agriculture will be dicult to
decarbonize completely by mid-century. Reaching
net-zero emissions will therefore require removing
carbon dioxide from the atmosphere, using
processes and technologies that are rigorously
evaluated and validated. This requires scaling up
land carbon sinks as well as engineered strategies.
Figure ES-2 illustrates how the five key transformations
can combine in dierent pathways to achieve net-
zero emissions by 2050. The exact pathway will
depend on how quickly change occurs across dierent
sectors. Nevertheless, some broad patterns are
clear. For example, energy system transformations
contribute roughly 4.5 gigatons of CO
2
equivalent per
year (Gt CO
2
e/yr.) of overall emissions reductions,
or about 70% of overall reductions. These energy
emissions reductions are delivered by cutting energy
waste, decarbonizing electricity, and transitioning
energy sources including through fuel switching and
electrification. Addressing non-CO
2
gases, including
methane, nitrous oxide, and fluorinated gases, reduces
another 1 Gt of annual emissions. Enhancing land sinks
and scaling up CO
2
removal technologies also deliver
about 1 Gt of negative emissions. While these figures
are a helpful rough guide, the exact contribution from
each area varies between pathways (as shown in Figure
ES-2). The eventual U.S. pathway to net-zero emissions
will depend on the evolution of technologies, the
specifics of policy and regulatory packages, and factors
such as economic growth, sociodemographic shifts, and
market prices for commodities and fuels across the next
three decades.
ACHIEVING NET-ZERO BY NO LATER THAN 2050
REQUIRES SUSTAINED, COORDINATED ACTION
SPANNING FOUR STRATEGIC PILLARS:
1. FEDERAL LEADERSHIP. Federal leadership is critical
to reduce emissions 50-52% below 2005 levels in
2030 and set up the economy to achieve net-zero
emissions by 2050. This could include investments
and incentives that support the deployment
of clean technologies in all sectors, policies to
enhance and support our natural and working lands,
partnerships to catalyze market transformation,
improved integration of climate into financial
markets including enhanced climate risk disclosure,
and the promulgation and enforcement of new and
existing regulations rooted in law.
7
THE LONG-TERM STRATEGY OF THE UNITED STATES
2. INNOVATION. In driving the deployment of currently
competitive technologies as rapidly as possible,
federal policies will serve to further reduce costs
through economies of scale and learning-by-doing.
In addition, new technologies will be necessary to
drive deeper reductions in the late 2020’s through
2050. Federally-supported research, development,
demonstration, and deployment can be the prime
mover—along with federal, subnational, and private
sector procurement—to carry new carbon-free
technologies and processes from the lab to U.S.
factories to the market. Research and development
today will lay the technology foundation necessary
to maximize economic benefits from the post-2030
transformation to net-zero.
3. NON-FEDERAL LEADERSHIP. The U.S. federal system
is based on the national government sharing power
with elected governments at subnational levels. In
our system, policy authorities related to economic
activity, energy, transportation, land use, and more
are shared with Tribal governments, states, cities,
counties, and others. U.S. climate action therefore
necessarily spans all levels of government. Recent
trends demonstrate the significant impacts that
these subnational policies can have on the overall
U.S. emissions trajectory, in ways that complement
national policies and can provide a broader base for
learning and for accelerating action.
Figure ES-2: Emissions Reductions Pathways to Achieve 2050 Net-Zero Emissions in the United States.
Achieving net-zero across the entire U.S. economy requires contributions from all sectors, including:
eciency, clean power, and electrification; reducing methane and other non-CO
2
gases; and enhancing
natural and technological CO
2
removal. The left side of the figure shows a representative pathway with high
levels of action across all sectors to achieve net-zero by 2050. The right side shows a set of alternative
pathways depending on variations in uncertain factors such as trends in relative technology costs and the
strength of the land sector carbon sink.
ALTERNATE PATHWAYS TO 2050 NET-ZERO
REPRESENTATIVE PATHWAY TO 2050 NET
-ZERO
8
THE LONG-TERM STRATEGY OF THE UNITED STATES
IF OTHER MAJOR ECONOMIES ADOPT SIMILAR
AMBITION, WE CAN KEEP 1.5°C WITHIN REACH.
The U.S. currently emits 11% of annual global GHGs
(second to China, which emits 27% of the global total).
Cutting our emissions at least in half by 2030 and
eliminating our emissions by 2050 will therefore make
an important direct contribution to keeping a safer
1.5°C future within reach. These eorts will also spur
cost reductions for clean technologies through scale
and learning-by-doing. More importantly, U.S. climate
leadership has already helped propel other major
economies to adopt 2030 NDCs that are aligned with
the imperative to cut global emissions at least 40% by
2030 to improve our chances of limiting global warming
to less than 1.5°C. At the Leaders’ Summit on Climate in
April of 2021, President Biden announced our ambitious
NDC, joined by Canadian and Japanese leaders who
also set strong new 2030 targets. The European Union
(EU) and United Kingdom (UK) had already set strong
targets and, since the Summit, others, including the
Republic of Korea and South Africa, have come forward
with NDCs that achieve the pace of reductions that
would be needed globally to keep 1.5°C within reach.
These countries represent well over half of the global
economy, but further action by other major economies
will be necessary to ensure the 1.5°C target is met.
4. ALL-OF-SOCIETY ACTION. The long-term
transformations to get to 2050 net-zero emissions
will require the United States to bring all its
greatest strengths to bear, including innovation,
creativity, and diversity. Already, many non-
governmental organizations are acting ambitiously
to address climate change within their own
operations or support the overall transition of the
U.S. economy. Even more broad-based engagement
on research, education, and implementation
through our universities, cultural institutions,
investors, businesses, and other non-governmental
organizations will be required to reach our 2050
goal.
IMPLEMENTATION IS UNDERWAY.
These four principles form the core of our strategy to
achieve our 2030 NDC and 100% clean electricity by
2035. We are moving rapidly, rooted in actions from
across the federal government and other governmental
and non-governmental actors. These actions and
policies are part of our Long-Term Strategy and are
described in a forthcoming companion report to this
document, The U.S. National Climate Strategy (NCS)
[2]. The NCS describes an overarching approach that
covers all aspects of federal action, which will also
support broader non-federal and all-of-society eorts.
Both the NCS and this Long-Term Strategy have been
informed by a robust stakeholder engagement process.
These actions provide the near-term implementation
momentum to achieve the 2030 NDC, 2035 100%
clean electricity goal, and the 2050 net-zero goal.
Globally, this is the moment for all the world’s major
economies to act to rapidly reduce emissions to meet
ambitious 2030 NDC targets and to develop and
communicate strategies to achieve ambitious 2050
net-zero goals.
FOUR COMPONENTS
OF U.S. REPORTING
ON CLIMATE ACTIONS
AND STRATEGY
1. The U.S. National Climate Strategy details how we
will deliver our U.S. NDC for 2030 [2]. It focuses on the
immediate policies and actions that will put America on
track to reduce emissions by 50-52% below 2005 levels in
2030 and put in place the technology and infrastructure
necessary to achieve net-zero emissions no later than
2050.
2. The Long-Term Strategy of the United States to Reach
Net-Zero Emissions by 2050 (this report), pursuant
to Article 4.19 of the Paris Agreement, shows how these
current and near-term policies and other actions across
the country, as described in the NCS, deliver a pathway
through the 2030s and 2040s to reach our 2050 net-zero
goal. As a contribution under the Paris Agreement, it is part
of a process that serves to support enhanced global action
and ambition.
Communicating actions and progress toward climate goals is a critical component
of transparency to support global ambition under the Paris Agreement. The United
States is committed to these principles and, accordingly, is issuing four reports
detailing complementary aspects of our current climate activities and planned
strategy. The same key assumptions and methodologies are shared in the analytics
that inform all four reports. Each report serves a dierent role in communicating the
overall situation and strategy of the United States, and there are details in each that
are not reproduced across all reports. Together they present a vision for our climate
strategy and emissions pathways.
3. The U.S. National Communication and Biennial Report
provides detailed information on existing policies and
measures across all areas of U.S. climate action as of
December 2020 [7]. It fulfills our obligations for reporting
and transparency under the UN Framework Convention
on Climate Change (UNFCCC) and fits into a broader
international reporting framework in which other countries
also participate.
4. The U.S. Adaptation Communication provides forward-
looking priorities for accelerating adaptation and building
resilience domestically and abroad [8]. It outlines domestic
climate impacts and vulnerabilities, progress on adaptation,
lessons learned, and immediate policies and other
approaches that will increase adaptive capacity, enhance
resilience, and reduce vulnerability to climate change. It
complements and builds upon resilience and adaptation
actions laid out in the National Climate Strategy and U.S.
National Communication and Biennial Report.
THE LONG-TERM STRATEGY OF THE UNITED STATES
9
10
THE LONG-TERM STRATEGY OF THE UNITED STATES
Climate change already inflicts serious damage on
the United States and the world, particularly the most
vulnerable that are least equipped to adapt—and the
science is clear that, without faster global action, these
impacts will become much more frequent and severe.
Two recent reports from the Intergovernmental Panel
on Climate Change [1] [9] arm with robust scientific
confidence the need to keep warming under 1.5°C to
reduce the greatest global risks and avoid significant,
wide-ranging, and severe impacts. To keep 1.5°C within
reach, the United States has a goal of achieving net-zero
emissions economy-wide by no later than 2050 [3] [4] [5].
The Paris Agreement establishes a framework to rapidly
increase global ambition to hold warming well below
2°C while pursuing eorts to limit warming to 1.5°C. This
framework includes nationally determined contributions
(NDCs)—commitments that target near-term emissions
reductions, review progress, and seek to extend and
strengthen their NDCs in regular 5-year cycles. The
Paris Agreement also specifically calls on all countries
to “formulate and communicate their long-term, low
GHG emission development strategies.” Such Long-
Term Strategies support global ambition by encouraging
countries to understand their options and set their own
longer-term emissions reduction goals [10]. In developing
and communicating these strategies [11], countries can
foresee and address challenges such as slow infrastructure
turnover or the need for just transitions from fossil fuels
and other high-emission technologies. Developing and
sharing publicly these near- and long-term strategies
helps elucidate and manage path dependencies and better
connect short-term and long-term objectives. Accordingly,
this process can both guide national action and encourage
greater global ambition over time.
The United States is simultaneously pursuing multiple
climate mitigation goals (Figure 1). Each goal serves as
an important milestone toward rapidly reducing our GHG
emissions to net-zero. While this report emphasizes the
longer period of 2021-2050, the overall U.S. strategy
integrates actions for both near-term and 2050 goals:
• The 2030 NDC of 50-52% reductions below 2005
levels, covering all sectors and all gases
• The goal for 100% carbon pollution-free electricity
by 2035
• The goal for net-zero emissions no later than 2050.
CHAPTER 1:
AN INTEGRATED U.S. CLIMATE STRATEGY
TO REACH NET-ZERO EMISSIONS BY 2050
11
THE LONG-TERM STRATEGY OF THE UNITED STATES
These near-term actions are being implemented rapidly,
rooted in policies from across the federal government
and other governmental and non-governmental actors
in the United States. These actions and policies are
described in detail in a companion to this document,
The U.S. National Climate Strategy (NCS) [2]. The
NCS lays out an overarching policy approach being
undertaken today that covers all aspects of federal
action, in support of all-of-society eorts. These actions
provide the near-term implementing momentum to
achieve the 2030 NDC, meet the 2035 100% clean
electricity goal, and put the U.S. in a strong position
to take the additional actions necessary to achieve
net-zero by 2050. The information on near-term
implementation in the NCS should therefore be viewed
as integral to the U.S. Long-Term Strategy. Accordingly,
although this report focuses on the period from 2021 to
2050, it refers to the NCS for further descriptions of near-
term implementation of long-term goals.
The Biden Administration consulted diverse stakeholders
to inform the overall U.S. climate strategy that is reflected
in the U.S. Long-Term Strategy (LTS) report. This
consultation covered a wide range of stakeholders from
major unions that work on behalf of millions of American
workers, to groups representing tens of millions of
advocates, fence line communities, and young Americans.
Engagement to develop our strategy also included groups
representing scientists; hundreds of governmental
leaders like governors, mayors, and Native American
leaders; hundreds of businesses; hundreds of schools
and institutions of higher education; as well as with many
specialized researchers focused on questions of pollution
Figure 1: United States historic emissions and projected emissions under the 2050 goal for net-zero.
This figure shows historical U.S. GHG emissions from 1990 to 2019, the projected pathway to the
2030 NDC of 50-52% below 2005 levels, and the 2050 net-zero goal. The United States has also set a
goal for 100% clean electricity in 2035. That goal is not an economy-wide emissions goal so does not
appear in this figure, but it will be critical to support decarbonization in the electricity sector, which will
in turn help the U.S. reach its 2030 and 2050 goals.
17% BELOW 2005
LEVELS IN 2020
26-28% BELOW 2005
LEVELS IN 2025
50-52% BELOW 2005
LEVELS IN 2030
Net-Zero
IN 2050
0
1
2
3
4
5
6
7
0%
-10%
-20%
-30%
-40%
-50%
-60%
-70%
-80%
-90%
-100%
1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050
Emissions (Gigatons CO
2
e)
Percent Below 2005
HISTORIC EMISSIONS
17% BELOW 2005 LEVELS IN 2020
U.S. PROJECTED EMISSIONS UNDER 2025 TARGET
U.S. PROJECTED EMISSIONS UNDER 2030 TARGET
U.S. PROJECTED EMISSIONS UNDER 2050 GOAL
12
THE LONG-TERM STRATEGY OF THE UNITED STATES
reduction. NCS report referenced above has similarly
been developed through extensive consultations of
diverse stakeholders, whose perspectives and input have
informed the overall climate strategy that is reflected in
this LTS report.
The United States presented its first Long-Term Strategy
report in 2016 [12], focused on reducing net GHGs 80-
90% below 2005 levels by 2050. In 2021, the United
States put forward a new, ambitious goal of net-zero
emissions no later than 2050. This report presents
an updated 2021 Long-Term Strategy of the United
States that defines multiple pathways for the American
economy to achieve net-zero emissions by 2050. It
includes analysis of what transformational pathways
to net-zero could look like over time for emissions in
dierent sectors and for dierent GHGs. The report draws
from a diverse analytical toolkit,
4
integrating insights
from a global integrated assessment model covering all
greenhouses and economic sectors, a national CO
2
model
with high resolution on the electricity sector, models of
U.S. land sector, and more. The analysis presented here
was based on an interagency eort and is grounded in
a broader body of existing scholarship and literature
4
These core analyses in this report are shared with two companion
volumes, the U.S. National Climate Strategy and the U.S. National
Communication and Biennial Report to the UNFCCC.
for how to understand both near- and long-term high-
ambition emissions pathways in the national and global
context. While the analyses presented here provide new
and original insights, they also draw from and reference
this broader body of work.
This report is organized as follows. Chapter 2 focuses
on the decisive decade from now to 2030 and highlights
the U.S. priorities which will both dramatically reduce
GHG emissions and lay the foundation for achieving
net-zero emissions no later than 2050. Chapter 3 gives
an overview of the economy-wide emissions pathways
to 2050. Chapter 4 describes pathways for energy-
related CO
2
emissions reduction across electricity,
transportation, buildings, and industry. Chapter 5
presents the key opportunities for methane and other
non-CO
2
emissions reductions, including in the energy,
waste, agriculture, and industrial sectors. Chapter 6
focuses on CO
2
removals through lands and technologies
for carbon dioxide removal. Chapter 7 presents a vision
of the many benefits that will be created on the path to
a net-zero emissions economy, including transformative
improvements in public health, avoided climate damages,
enhanced climate security, and job growth. Finally,
Chapter 8 concludes with a vision of the U.S. accelerating
global climate progress with ambitious domestic climate
action.
THE U.S. 2050 NET-ZERO GOAL
The United States has set a goal of net-zero
emissions by no later than 2050.
The goal includes all major GHGs (CO
2
, CH
4
, N
2
O, HFCs, PFCs, SF
6
, NF
3
) and is economy-wide. The goal is on a net
basis, including both sources of emissions and removals. It does not include emissions from international aviation
or international shipping. At this time, the United States does not expect to use international market mechanisms
toward achievement of this net-zero goal. Progress toward the goal will be assessed and the U.S. LTS may be updated,
as appropriate.
13
THE LONG-TERM STRATEGY OF THE UNITED STATES
Putting the United States on a path to net-zero
emissions economy-wide no later than 2050 requires
taking transformative actions this decade and achieving
near-term milestones in line with this goal. This is
why the United States set an economy-wide target
of reducing its net GHG emissions by 50-52% below
2005 levels in 2030 (Figure 2). The United States will
also soon release a complementary report, The U.S.
National Climate Strategy (NCS) [2], following this 2021
Long-Term Strategy, to provide additional detail on the
steps the United States is taking to achieve our 2030
target—and in doing so, to put the United States on
a track to achieve its 2050 net-zero goal. This 2030
commitment anchors the U.S. approach during this
decade to build a sustainable, resilient, and equitable
economy by rapidly deploying widely available low-
carbon technologies and investing in the infrastructure,
innovation, and workforce that is the foundation of this
economic transformation.
This decade will be decisive—and the benefits
of achieving our 2030 goal will be significant.
Transitioning to a clean energy economy will create
between 500,000 and one million net new jobs
across the country this decade [13] [14]. Moreover,
reducing air pollution through these eorts will avoid
85,000–300,000 premature deaths [14] [15]. This
transition will require a multi-pronged approach involving
the private sector, sub-national governments, and
federal government to generate new regulations, direct
investment, and programs at all levels of government.
Near-term actions to accelerate this transition are being
implemented rapidly, rooted in actions from across the
federal government and other governmental and non-
governmental actors in the United States. These actions
and policies are described in detail in the NCS report,
which lays out an overarching policy approach being
undertaken today—informed by ongoing engagement of
diverse stakeholders—that covers all aspects of federal
action, in support of all-of-society eorts. These actions
provide the near-term implementing momentum to
achieve the 2030 NDC, 2035 100% clean electricity
goal, and the 2050 net-zero goal. A summary of these
elements is provided below.
CHAPTER 2:
THE DECISIVE DECADE TO 2030
14
THE LONG-TERM STRATEGY OF THE UNITED STATES
2.1 ELECTRICITY
Fast and cost-eective emission-reducing investments
are available in the electric power sector, which is
currently the second-largest producer of emissions in the
United States. That is why the United States set a goal
to reach a 100% carbon pollution-free electricity system
by 2035, which can be achieved through multiple cost-
eective technology and investment pathways. In fact,
this transition has already been accelerating in recent
years—driven by plummeting costs of key technologies
like solar, onshore wind, oshore wind, and batteries,
as well as enhanced policies and increased consumer
demand for clean, reliable, and aordable power.
Further acceleration of clean energy deployment can be
catalyzed through providing incentives and standards
to reduce pollution from power plants; investing in
technologies to increase the flexibility of the electricity
system, such as transmission, energy eciency,
energy storage, smart and connected buildings, and
non-emitting fuels; and leveraging carbon capture and
storage (CCS) and nuclear. Significant deployment
of energy eciency reduces overall demand and
can lower peak load, reducing grid capital costs and
making investments in carbon-free power generation
go further. Research, development, demonstration,
and deployment of new software and hardware
solutions will further support the transformation to a
carbon pollution-free, resilient, reliable, and aordable
electricity system.
Figure 2: United States historic emissions and projected emissions under the 2030 NDC target.
This figure shows the historical trajectory of U.S. GHG emissions and the pathway to the 2030
GHG reduction targets. The 2030 NDC target is ambitious, and policies and measures have put the
American economy on a declining emissions trend consistent with these goals. The 2030 targets
put the United States on a faster track than a straight-line path to net-zero in 2050 would require.
17% BELOW 2005
LEVELS IN 2020
26-28% BELOW 2005
LEVELS IN 2025
50-52% BELOW 2005
LEVELS IN 2030
0
1
2
3
4
5
6
7
0%
-10%
-20%
-30%
-40%
-50%
-60%
-70%
-80%
-90%
-100%
1990 1995 2000 2005 2010 2015 2020 2025 2030
Emissions (Gigatons CO
2
e)
Percent Below 2005
HISTORIC EMISSIONS
17% BELOW 2005 LEVELS IN 2020
U.S. PROJECTED EMISSIONS UNDER 2025 TARGET
U.S. PROJECTED EMISSIONS UNDER 2030 TARGET
15
THE LONG-TERM STRATEGY OF THE UNITED STATES
2.2 TRANSPORTATION
Vehicles have become the largest emissions source
in the United States—driven by fossil fuel use in light-
duty cars, trucks, and SUVs, followed by medium- and
heavy-duty trucks, buses, air, o-road vehicles, rail,
and shipping. There are many opportunities to reduce
GHG emissions from transportation while also saving
money for households and businesses, improving
environmental quality and health in communities,
and providing more choices for moving people and
goods. At its core, this requires electrifying most
vehicles to run on ever-cleaner electricity and shifting
to low-carbon or carbon-free biofuels and hydrogen in
applications like long-distance shipping and aviation.
To support this outcome, the United States set a goal
for half of all new light-duty cars sold in 2030 to be
zero-emission vehicles, to produce 3 billion gallons of
sustainable aviation fuel by 2030, and to accelerate
deployment and reduce costs in every mode of
transportation. This will occur through lower vehicle
costs; fuel economy and emissions standards in light-,
medium- and heavy-duty vehicles; incentives for zero-
emission vehicles and clean fuels; investment in a new
charging infrastructure to support multi-unit dwellings,
public charging, and long-distance travel; scaling up
biorefineries; comprehensive innovation investments to
reduce hydrogen costs; and investment in infrastructure
that supports all modes of clean transportation—such
as transit, rail, biking, micro mobility, and pedestrian
options.
Making progress this decade requires investing in
domestic manufacturing and reliable supply chains for
clean fuels, batteries, and vehicles. In addition, research,
development, demonstration, and deployment of
electrification and zero- or low-carbon fuels for aviation
and shipping will ensure we have the technology
to continue reducing emissions across the entire
transportation sector in the years leading to 2050.
2.3 BUILDINGS
Buildings and their energy-consuming systems—
electricity used and fossil fuels burned on site for heating
air, heating water, and cooking—have long lifetimes.
Therefore, the priority in this decade is to rapidly
improve energy eciency and increase the sales share
of clean and ecient electric appliances—including
heat pumps for space conditioning, heat pump water
heaters, electric and induction stoves, and electric
clothes dryers—while also improving the aordability of
energy and the equitable access to ecient appliances,
eciency retrofits, and clean distributed energy
resources in buildings. This includes investment in public
buildings such as public housing, government facilities,
schools, and universities. Research and demonstration
investments now will also advance new solutions for
ecient, grid-interactive, and electrified buildings.
Achieving 100% clean power generation by 2035 will
also eliminate upstream emissions from electricity
and facilitate carbon-free and ecient electrification
of appliances and equipment in buildings. Moreover,
partnerships like the Environmental Protection Agency
(EPA) ENERGY STAR and the advancement of building
energy codes and appliance standards will ensure
that building envelopes, electric appliances, and other
equipment become increasingly ecient over time.
Ecient electric space heating and cooling and water
heating oer important opportunities to employ grid-
interactive demand to lower energy bills for households
and businesses while more cost-eectively utilizing
carbon-free electricity.
2.4 INDUSTRY
The industrial sector emits GHGs through multiple
complex pathways. This includes CO
2
emitted indirectly
through electricity and directly through on-site fossil
fuel combustion and power generation, as well as
emissions of CO
2
and non-CO
2
GHGs leaked from on-
site use or emitted through industrial processes (such
as cement production). Industrial decarbonization
can be delivered through energy eciency; industrial
electrification; low-carbon fuels, feedstock, and energy
16
THE LONG-TERM STRATEGY OF THE UNITED STATES
sources; and industrial CCS. Achieving clean power
by 2035 will eliminate the emissions from grid power
consumed by industry and make possible the carbon-
free electrification of certain industrial processes that
are currently dominated by fossil fuel use. Low- and
medium-temperature process heat are candidates
for industrial electrification in the near term through
increased use of industrial heat pumps, electric boilers,
or electromagnetic heating processes.
Additional technologies and process innovations are
also needed to address other industrial emissions,
including high-temperature heat and process emissions
from steel, petrochemical, and cement production.
Fundamentally new processes will be needed to address
the chemical process emissions associated with the
production of these commodity materials that have
large GHG emissions footprints. Energy eciency
measures make carbon-free electricity and other low-
carbon industrial fuels stretch as far as possible and as
early as possible.
The United States will also scale support for
related research, development, demonstration,
commercialization, and deployment of zero-carbon
industrial innovations. This includes incentives for
carbon capture and new sources of clean hydrogen—
produced from renewable energy, nuclear energy,
or waste—to power industrial facilities. To drive
the market for these solutions, the United States
government will also use its procurement power to
support early markets for these very low- and zero-
carbon industrial goods.
Additionally, monitoring and control technologies are
needed to prevent the release to the atmosphere of
non-CO
2
GHGs from industrial operations, including
methane, fluorinated gases, black carbon, and other
potent short-lived climate pollutants. The United
States has finalized regulations to phase down the use
of fluorinated gases consistent with our obligations
under the Kigali Amendment to the Montreal Protocol.
Addressing methane emissions will also require setting
stringent standards for oil and gas production and
investing in plugging leaks from coal, oil, and gas mines
and wells.
2.5 AGRICULTURE, FORESTRY, AND LAND USE
America’s vast lands provide opportunities to both
reduce emissions and sequester carbon. Capitalizing
on these opportunities includes: continuing to expand
forest area, extending rotation lengths, protecting forest
area, integrating trees into urban areas and agriculture,
scaling up climate-smart agricultural practices such as
cover crops, and employing rotational grazing on our
agricultural lands. Even more leverage can be derived
through programs and incentives to improve agricultural
productivity; such practices and technologies can free up
land for other uses as well as reduce agricultural methane
and N
2
O emissions through, for example, improved
manure management and improved cropland nutrient
management. Enhanced investment in forest protection
and forest management, along with science-based and
sustainable eorts to reduce the scope and intensity
of catastrophic wildfires and to restore fire-damaged
forest land, are vital to protecting and growing the largest
land sink. Alongside these eorts, the United States will
support nature-based coastal resilience projects including
pre-disaster planning as well as eorts to increase carbon
sequestration in waterways and oceans by pursuing
“blue carbon.” Finally, climate-smart practices can
also lower the emissions intensity of biofuels needed
for decarbonizing transportation. Actions taken now
and through this decade will ensure we maximize the
potential of our lands and waters to sequester carbon to
the greatest extent possible by 2050.
Across these sectors, the U.S. federal government is
working with Tribal governments, states, and localities
to support rapid deployment of new carbon-pollution-
free technologies and facilities while ensuring they
meet robust and rigorous standards for workers, public
and environmental safety, and environmental justice.
Accomplishing the goals this decade and setting up the
economy for further reductions after 2030 also requires
investment in innovation and U.S. manufacturing to lower
the cost of new technologies needed in the future, grow
the domestic manufacturing base and supply chains for
those technologies, and train the workforce needed.
17
THE LONG-TERM STRATEGY OF THE UNITED STATES
The decisive decade through 2030 is central to setting
the United States—and the world—on a pathway that
keeps warming of 1.5°C within reach. For all countries,
2030 is an essential waypoint that is part of a longer
path to reach global net-zero emissions by mid-century.
The ambitious policies and goals described in Chapter
2 will set the United States on a pathway to achieve
our 2030 target. At the same time, these actions will
also catalyze the longer-term changes in the American
energy, industrial, and land systems required to achieve
net-zero by 2050.
This chapter presents the results of a comprehensive
analysis undertaken to assess potential pathways to
net-zero emissions in the United States by no later than
2050. These pathways are all grounded in our strategy
to achieve our 2030 NDC and our goal of 100% carbon
pollution-free electricity by 2035. These transition
pathways are not only aordable, but, because of the
benefits from reduced climate change and improved
public health, they will also create wide-ranging benefits
(see Chapter 7). It will require ambitious action and
investment grounded in intensive engagement with
communities, workers, and businesses to ensure that the
benefits of the transition are equitably distributed—with
a focus on those communities that remain overburdened
and underserved.
3.1 ASSESSING MITIGATION OPPORTUNITIES
TO ACHIEVE NET-ZERO EMISSIONS
Achieving rapid emissions reductions requires
integrating near-term policy drivers with a strategy
to assess and manage longer-term factors like capital
stock turnover and technological innovation. To this
end, this LTS employs diverse analytical approaches
to project the impact of alternate assumptions about
policies, technologies, and other drivers. These aord
a broad understanding for what long-term net-zero
technology transformations would look like globally [16]
as well as providing roadmaps for how to aect those
transitions rapidly [17].
In light of the Paris goals to develop and communicate
national emissions reductions pathways, such analytical
approaches have also been applied to understanding
specific national circumstances and opportunities,
including those within the United States. Some of these
U.S.-specific studies focus on policy frameworks to drive
near-term action that would set the U.S. on a pathway
to longer-term net-zero or 1.5°C-compatible emissions
[18] [19] [20]. In parallel, others look at the potential
for integrating all-of-society strategies that include
diverse levels of government and other actors [21].
CHAPTER 3:
PATHWAYS TO 2050 NET-ZERO
EMISSIONS IN THE UNITED STATES
18
THE LONG-TERM STRATEGY OF THE UNITED STATES
Others have focused on overall long-term technological
transformations and associated emission reduction
strategies that would be necessary for reduction to
net-zero in the U.S. by 2050. Many of these 2050
studies address emissions reduction across the entire
economy and for all gases [14] [22] [23]; others focus on
specific areas or sectors such as energy, electricity [13]
[24], transportation [25], or manufacturing [26]. This
research has advanced thinking about what is possible
within the United States and what robust strategies to
reach 2050 net-zero could look like. The assessment
and analytical approaches presented here are original to
this report but also recognize the many insights oered
in this wider literature, including but not limited to
studies specifically on 2050 net-zero pathways. Insights
from this literature are consistent in what they tell us
about the critical elements supporting the long-term
emissions reduction trajectory for the United States.
This trajectory rests on the integration of five
complementary technological transformations:
1. DECARBONIZE ELECTRICITY. Electricity delivers
diverse services to all sectors of the American
economy. The transition to a clean electricity
system has been accelerating in recent years—
driven by plummeting costs for solar and wind
technologies, federal and subnational policies,
and consumer demand. Building on this success,
the United States has set a goal of 100% clean
electricity by 2035, a crucial foundation for net-zero
by 2050.
2. ELECTRIFY END USES AND SWITCH TO OTHER CLEAN
FUELS. We can aordably and eciently electrify
most of the economy—from cars to buildings and
industrial processes. In areas where electrification
presents technology challenges—for instance
aviation, shipping, and some industrial processes—
we can prioritize clean fuels like carbon-free
hydrogen and sustainable biofuels.
3. CUT ENERGY WASTE. Moving to cleaner sources of
energy is made faster, cheaper, and easier when
existing and new technologies use less energy
to provide the same or better service. This can
be achieved through diverse, proven approaches,
ranging from new and more ecient appliances and
the integration of eciency into new and existing
buildings, to sustainable alternate manufacturing
processes and the integration of eciency into new
and existing buildings.
4. REDUCE METHANE AND OTHER NON-CO
2
EMISSIONS.
Non-CO
2
gases such as methane, HFCs, nitrous
oxide, and others contribute significantly to
warming, with methane alone contributing fully
half of current net global warming of 1.0°C. There
are many profitable or low-cost options to reduce
non-CO
2
sources, such as implementing methane
leak detection and repair for oil and gas systems
and shifting from HFCs to climate-friendly working
fluids in cooling equipment. The U.S. is committed
to taking comprehensive and immediate actions
to reduce methane domestically. And through the
Global Methane Pledge, the U.S. and partners seek
to reduce global methane emissions by at least
30% by 2030, which would eliminate over 0.2°C
of warming by 2050. The U.S. will also prioritize
research and development to unlock the innovation
needed for deep emissions reductions beyond
currently available technologies.
5. SCALE UP CO
2
REMOVAL. In the three decades to
2050, our emissions from energy production can
be brought close to zero but certain emissions
such as non-CO
2
from agriculture will be dicult to
decarbonize completely by mid-century. Reaching
net-zero emissions will therefore require removing
carbon dioxide from the atmosphere, using
processes and technologies that are rigorously
evaluated and validated. This requires scaling up
land carbon sinks as well as engineered strategies.
There are many plausible pathways through 2050 to
achieving a net-zero emissions economy. However,
developments in these sectors over time are
interdependent. For example, widespread adoption
in leading energy eciency practices in buildings
could significantly impact overall electricity demand,
reducing the amount of new clean energy installations
19
THE LONG-TERM STRATEGY OF THE UNITED STATES
required. The insight that sectors are interdependent
demonstrates the importance of policy and incentives
to realize the benefits of decarbonization across
the economy. Recent developments in energy,
manufacturing, and information technology have
made swift and substantial reductions possible.
Well-designed policies can help to ensure rapid and
aordable economy-wide decarbonization. For example,
accelerated shifting to carbon-free power makes end-
use electrification an even more eective strategy
to drive down emissions. In addition, policies can
maximize the benefits of decarbonization and ensure
that underserved communities benefit equitably from
the transition to a clean energy system. For example,
inclusive investment programs to scale up financing
for ecient electric home upgrades can help level the
playing field for underserved households and ensure
eective consumer protections.
3.2 CURRENT U.S. GHG EMISSIONS TRENDS
IN 2021
Net U.S. GHG emissions peaked in 2007 [27] after
growing through much of the previous century, driven
mainly by combustion of fossil fuels to meet growing
demand for energy services. Since their peak, net U.S.
GHG emissions have declined, driven by a combination
of forces. Federal policy has played a crucial role,
including through sustained research and development
investments which propelled an initial shift from coal
to gas power and the simultaneous and now dominant
growth of renewables; incentives for renewables and
zero-emission vehicles; and sector-specific regulations
such as emissions standards for power plants, fuel
economy standards, and appliance eciency standards.
Tribal governments, U.S. states, cities, counties, and
other non-federal actors have played a similarly crucial
role across all sectors of the economy. Moreover,
this federal and subnational investment and policy
has propelled a virtuous cycle of technology cost
reductions inducing even larger markets for key carbon-
free technologies which, in turn, drives further cost
reductions through scale and learning.
3.3. ANALYSIS OF POTENTIAL U.S.
TRAJECTORIES TO NET-ZERO EMISSIONS
BY 2050
The new analysis presented here oers insights into
what the overall emissions profile for the United
States could look like between now and 2050 under
a set of alternate assumptions about the evolution
of technological costs, economic growth, and other
drivers to 2050. We use two economy-wide models
(GCAM and OP-NEMS), a range of sensitivity scenarios,
supplemental models for key sectors, and comparisons
to the growing literature on pathways to net-zero
emissions. This provides transparency on what the
possible pathways to 2050 net-zero might look like, and
how those dierent pathways would aect the evolution
of specific sectors and rates of deployment for specific
technologies.
The assessment presented in this chapter reflects model
outputs that are subject to several types of uncertainty.
The goal of showing these outputs is to illustrate the
evolution of the U.S. economy and resulting emissions
over time. While the technology assumptions and
policy goals for the decade to 2030 are largely
understood, there is increasing uncertainty after 2030
on how any individual technology or sector will evolve.
We show several dierent pathways based on alternate
assumptions. These sensitivities illustrate a range of
credible and plausible pathways to net-zero by 2050.
3.3.1 DESCRIPTIONS OF THE MODELS
Global Change Assessment Model (GCAM)
The LTS scenarios were produced in the Global Change
Analysis Model (GCAM) by the Pacific Northwest
National Laboratory. The Global Change Analysis
Model (GCAM) is an integrated assessment model
covering all major GHGs and all sectors of the economy,
linking the world's energy, agriculture, and land use
systems with a climate model. It is used to explore
the interactions of emissions-reducing investments
and activities across the U.S. and global economy. The
model is designed to assess climate change policies and
20
THE LONG-TERM STRATEGY OF THE UNITED STATES
technology strategies for the globe over long time scales.
GCAM runs in 5-year time steps from 2005 to 2100
and includes 32 geopolitical regions in the energy and
economy module and 384 land regions in the agriculture
and land use module. The model tracks emissions and
atmospheric concentrations of GHGs (CO
2
and non-
CO
2
), carbonaceous aerosols, sulfur dioxide, and reactive
gases and provides estimates of the associated climate
impacts, such as global mean temperature rise and sea
level rise. GCAM can incorporate emissions pricing and
emission constraints in conjunction with the numerous
technology options including solar, wind, nuclear, and
carbon capture and sequestration. The model has
been exercised extensively to explore the eect of
technology and policy on climate change and the cost
of mitigating climate change. GCAM is a community
model primarily developed and maintained at the Joint
Global Change Research Institute, a partnership between
Pacific Northwest National Laboratory (PNNL) and the
University of Maryland [28].
Oce of Policy – National Energy Modeling System
(OP-NEMS)
The LTS scenarios were constructed using a version
of the National Energy Modeling System (NEMS)
developed by the U.S. Department of Energy (DOE)
Oce of Policy (OP-NEMS). NEMS is an integrated
energy-economy modeling system for the United States
that projects the production, imports, conversion, and
consumption of energy, subject to assumptions on
macroeconomic and financial factors, world energy
markets, resource availability and costs, cost and
performance characteristics of energy technologies,
and demographics. The version of NEMS used in this
report has been run by OnLocation, Inc., with modeling
approach determined with input from the DOE Oce
of Policy and other DOE technology oces. Because
OP-NEMS projects only CO
2
emissions related to the
energy sector, external assumptions were provided
regarding non-CO
2
GHGs and land use, land-use change,
and forestry. OP-NEMS includes enhancements for clean
hydrogen, sustainable biofuels, and industrial carbon
capture, transport, and storage [29].
Global Timber Model (GTM)
The Global Timber Model (GTM) is a dynamic
intertemporal optimization economic model that
determines timber harvests, timber investments, and
land use optimally over time under assumed future
market, policy, and environmental conditions. This
model’s approach provides a simulation of harvesting,
planting, and management intensity decisions that
landowners might undertake in response to timber
and carbon market demands, including future price
expectations. These activities include aorestation
and land use change, forest management, and forest
products activity in response to policies and markets.
The model generates projections using detailed
biophysical and economic forestry data for dierent
countries or regions globally, including the U.S., China,
Canada, Russia, and Japan. It used macroeconomic
data from Annual Energy Outlook 2021 for the U.S.
and global parameters from Shared Socioeconomic
Pathway 2 (SSP2) [30]. The model has been widely used
to assess forest dynamics and carbon outcomes under
various demand and land carbon sink scenarios, climate
impacts, and other applications [31] [32].
Forestry and Agriculture Sector Optimization Model
with Greenhouse Gases (FASOM-GHG)
The Forestry and Agriculture Sector Optimization
Model with Greenhouse Gases (FASOM-GHG) model
is a partial-equilibrium dynamic intertemporal, price-
endogenous, mathematical programming model
depicting land transfers and other resource allocations
between and within the agricultural and forest sectors
in the United States. FASOM-GHG includes detailed
representations of agricultural and forest product
markets, contemporary forest inventories, intersectoral
resource competition and land change costs, and costs
of mitigation strategies. The results from FASOM-
GHG yield a dynamic simulation of prices, production,
management, consumption, GHG eects, and other
environmental and economic indicators within these
two sectors, under the chosen policy scenario. The
result provides insight into cross-sectoral inter- and
intra-regional responses to policy stimuli reflecting
21
THE LONG-TERM STRATEGY OF THE UNITED STATES
the spatial heterogeneity in production of agriculture
and forestry products across the U.S. To date, FASOM-
GHG and its predecessor models have been used to
examine the eects of GHG mitigation policy, climate
change impacts, public timber harvest policy, federal
farm program policy, bioenergy prospects, and pulpwood
production by agriculture among other policies and
environmental changes [33].
U.S. Department of Agriculture Forest Service
Resources Planning Act (RPA) modeling system
The LTS scenarios reflect results from the U.S. Department
of Agriculture (USDA) Forest Service Resources Planning
Act (RPA) modeling system which comprises the Forest
Dynamics model, integrated and harmonized with the
USDA Forest Service RPA Land Use Change Model and
the Forest Resource Outlook Model (FOROM) Global
Trade Model [34]. This modeling system supports the
projections of renewable resources across the U.S. in
the USDA 2020 Resources Planning Act Assessment.
Projections were developed under current climate
conditions without CO
2
fertilization and values are added
to USDA agriculture soils projections. The storage and
flux of carbon in harvested wood products and solid waste
disposal sites was projected using FOROM.
U.S. EPA Non-CO
2
Marginal Abatement Cost (MAC)
Model and Report
The U.S. EPA Non-CO
2
Marginal Abatement Cost (MAC)
Model is a bottom-up engineering cost model that
evaluates the cost and abatement potential of non-CO
2
mitigation technologies [35]. The associated non-CO
2
mitigation report [36] provides a comprehensive economic
analysis on the costs of technologies to reduce non-CO
2
gases and the potential to reduce them by sector.
3.3.2 SCENARIO DESCRIPTIONS
& KEY ASSUMPTIONS
The LTS analysis includes multiple scenarios highlighting
dierent pathways for achieving net-zero GHG emissions
by 2050. The figures in this chapter present results for a
range of assumptions including the land sink, technologies
(i.e., carbon dioxide removal, sector-specific
technologies, and non-CO
2
mitigation technologies),
energy prices, population, and economic growth.
The advanced LTS scenario assumptions account for
currently available opportunities as we build back from
the pandemic by using advanced assumptions for
electricity, transportation, industry, and buildings as
modeled in GCAM and OP-NEMS.
The underlying assumptions in the scenario sets are
as follows. Carbon removal levels represent the sum of
the net land sink, derived from modeled projections of
land use, land use change, and forestry (LULUCF), and
plausible levels of carbon dioxide removal technology
adoption such as biomass energy with CCS and direct
air capture from the literature [37] [38]. The combined
carbon removals from these sources are roughly 1,000,
1,400, and 1,800 MtCO
2
per year in 2050 over the
low, medium, and advanced cases, respectively. The
advanced and lower technology assumptions for the
electricity and transportation sectors rely largely upon
the National Renewable Energy Laboratory’s Annual
Technology Baseline. The advanced assumptions
for the buildings and industrial sectors draw on the
existing literature and programmatic goals for the
advanced cases and slower improvements in the lower
cases, which are more aligned with standard model
parameters. For non-CO
2
reductions, the advanced
technology assumptions accelerate the availability of
low-cost technologies but do not alter long-term costs.
Oil and natural gas prices are calibrated to the 2021
EIA Annual Energy Outlook’s oil and gas supply cases
in the reference scenario, i.e., without a net-zero 2050
target. Population and GDP, the final set of assumptions,
span compound annual growth rates from 2020 to
2050 of 0.5% to 0.7% for population and 1.1% to 1.8%
for GDP. Also, the LULUCF modeling eort included
the use of 5 dierent models to generate business as
usual and potential mitigation outcomes from dierent
land-based activities, including aorestation, improved
forest management, harvested wood products storage,
and fire reduction techniques. This exercise included
alignment of several key inputs and parameters,
including use of input data from the Forest Inventory
and Analysis database and, in some cases, application
22
THE LONG-TERM STRATEGY OF THE UNITED STATES
of Shared Socioeconomic Pathway (SSP) 2 information
for macroeconomic drivers. The land use models applied
in this analysis did not incorporate assumptions of
demand of CCS or bioenergy as mitigation options, as
these modeling aspects were accommodated in GCAM
and OP-NEMS.
3.4 ECONOMY-WIDE PATHWAYS TO 2050
NET-ZERO EMISSIONS
Achieving the 2050 net-zero goal will require reducing
net U.S. emissions from roughly 6.6 Gt CO
2
e in 2005
(and 5.7 Gt CO
2
e in 2020), to zero by no later than 2050.
As described above, this reduction can result from
combinations of five major categories of action: energy
eciency; decarbonizing electricity; fuel switching and
energy transitions; sequestering carbon through forests,
soils, and CO
2
removal technologies; and reducing
non-CO
2
emissions. Figure 3 presents a vision for how
such categories of action can combine to reach net-
zero. This figure shows a representative pathway from
2005 net emissions levels through 2050 in the form of
a waterfall chart (the left-hand side of the figure). This
representative pathway provides a rough approximation
for reaching net-zero emissions using contributions
from all sectors.
Table 1: Long-Term Strategy Scenarios. To explore multiple ways to reach our net-zero emissions goal in
2050, this analysis includes twelve scenarios (shown in the left most column of the table). The ‘Balanced
Advanced’ scenario includes medium levels of carbon removals from the atmosphere through our land
use, land use change, and forestry (LULUCF) sink and carbon dioxide removal (CDR) technologies, and
advanced technology assumptions allowing for a balanced approach across sectors. The next six scenarios
explore lower technology assumptions for electricity, transportation, industry, buildings, non-CO
2
, and
carbon removals, respectively. Next is a scenario that includes higher levels of carbon removals combined
with lower technology assumptions for multiple sectors. The last four scenarios explore high and low oil
and gas price sensitivities, and high and low population and GDP growth projections.
Table for LTS
LTS Scenario
Technology Assumptions by Sector
Model(s) Used
Carbon
Removal
Electricity Transportation Industry Buildings Non-CO
2
GCAM OP-NEMS
Balanced Advanced
Medium Advanced Advanced Advanced Advanced Advanced x
Lower Non-CO
2
Medium Advanced Advanced Advanced Advanced Lower x
Lower Buildings
Medium Advanced Advanced Advanced Lower Advanced x
Lower Industry
Medium Advanced Advanced Lower Advanced Advanced x
Lower
Transportation
Medium Advanced Lower Advanced Advanced Advanced x
Lower Electricity
Medium Lower Advanced Advanced Advanced Advanced x
Lower Removals
Lower Advanced Advanced Advanced Advanced Advanced x x
Higher Removals /
Lower Technology
Higher Advanced Lower Lower Lower Lower x x
High Oil & Gas Price
Medium Advanced Advanced Advanced Advanced Advanced x
Low Oil & Gas Price
Medium Advanced Advanced Advanced Advanced Advanced x
High Population &
GDP
Medium Advanced Advanced Advanced Advanced Advanced x
Low Population &
GDP
Medium Advanced Advanced Advanced Advanced Advanced x
23
THE LONG-TERM STRATEGY OF THE UNITED STATES
The right-hand side of the figure shows seven additional
scenarios from our analysis that are based on dierent
assumptions about how technologies and policies will
evolve over time. This includes a “balanced advanced”
scenario with high levels of action across all sectors, as
well as scenarios where one of the sectors (buildings,
industry, transportation, electricity, non-CO
2
, land sink)
contributes a lower level of reductions. These alternate
scenarios serve to illustrate how the balance across
technologies and policy strategies could vary while still
reaching the net-zero 2050 goal.
Several broad lessons from this figure are clear. First,
in the absence of additional policies, emissions would
remain largely flat moving forward. Results in the figure
show reductions from a baseline scenario to 2050—
that means that only reductions beyond the baseline
scenario are reflected in the colored bars. Achieving net-
zero emissions will require actions that go far beyond
business as usual.
Second, roughly 4.5 Gt of the 6.5 Gt annual reduction
from 2005 levels will likely come from transforming
the energy system. This starts with decarbonizing
Figure 3: Emissions Reductions Pathways to Achieve 2050 Net-Zero in the United States.
Achieving net-zero across the entire U.S. economy requires contributions from all sectors,
including: eciency, clean power, and electrification; reducing methane and other non-CO
2
gases; and enhancing natural and technological CO
2
removal. The left side of the figure shows a
representative pathway with high levels of action across all sectors to achieve net-zero by 2050.
The right side shows a set of alternative pathways depending on variations in uncertain factors
such as trends in relative technology costs and the strength of the land sector carbon sink.
ALTERNATE PATHWAYS TO 2050 NET-ZERO
REPRESENTATIVE PATHWAY TO 2050 NET
-ZERO
24
THE LONG-TERM STRATEGY OF THE UNITED STATES
electricity by shifting to renewables and other
emissions-free power. This shift could lead to over
1 Gt of annual reduction by 2050. A second pillar of
energy transformation is simply to use energy more
eciently to provide the same services. Solutions
like better insulation, advanced heat pumps for
space and water heating, and ecient computers
and electronics can save consumers billions on their
annual energy bills. Cutting energy waste also reduces
the rate of investment needed for new clean energy
generation as demand grows. This pillar alone could
contribute roughly 1 Gt of annual reductions by 2050.
A third pillar of energy transformation is to switch
as many uses as possible to clean energy—including
clean electricity, but also including low-carbon
fuels and clean hydrogen. Ecient electrification of
transportation, buildings, and other end uses can also
transform the energy sector by reducing overall energy
demand. Electric motors in vehicles, for example, are
approximately three times more ecient than internal
combustion engines, and electric heat pumps are up
to three times more ecient than heating with natural
gas or electric resistance. These activities would lead
to nearly 2 Gt of annual reductions by 2050.
Third, other non-CO
2
GHG emissions represent a
critical component of the overall reduction strategy,
collectively representing roughly 0.5 Gt of reductions
by 2050. These gases have sources across many
sectors and include methane emissions from
agriculture, waste management, and fossil fuel use,
HFCs used in refrigeration, and N
2
O from agriculture
and industry. Such gases often oer low cost and high
impact reductions. For example, globally, methane
accounts for half of the net 1.0°C of warming already
occurring. Because of its relatively short lifetime in
the atmosphere, compared to CO
2
, rapidly reducing
methane emissions is the single most eective strategy
to reduce warming over the next 30 years and is
crucial in keeping to the 1.5°C limit. The United States
co-leads with the EU the Global Methane Pledge that
aims to eliminate over 0.2°C of potential warming by
2050 by cutting global methane pollution at least 30%
by 2030 relative to 2020 levels. As of October 2021,
over 30 countries representing about 30% of global
emissions and 60% of the global economy had joined
the Pledge (See Box in Chapter 5). As detailed in the
NCS, the United States is implementing comprehensive
actions to drive down methane in this decade, including
new standards for landfills and oil and gas operations
as well as major investments to remediate abandoned
coal, oil, and gas mines and wells. The United States is
also committed to incentives and innovations to reduce
agricultural methane and agricultural N
2
O emissions.
Finally, a global HFC phasedown is expected to avoid up
to 0.5°C of global warming by 2100.
Fourth, removing CO
2
from the atmosphere is a
necessary component for reaching net-zero. Although
most emissions across the economy can be eliminated
through the above strategies, a few processes or
activities that lead to emissions are currently dicult
or costly to eliminate or have no viable existing
substitutes, and despite many available cost-eective
mitigation opportunities, non-CO
2
GHG emissions
cannot be fully reduced to zero. This means that
reaching net-zero will require additional contributions
from removals until viable zero-emission solutions
are developed and deployed. Overall, these removals
would come from two broad categories of activities.
One is through nature-based approaches that rely on
natural carbon sinks—land and ocean—by expanding
or enhancing conservation, restoration, sustainable
management and other activities that would enhance
natural removal of carbon as well as protect our
vital natural ecosystems and related services and
biodiversity. A second set of approaches is through
various technologies and processes that directly
capture CO
2
from the atmosphere and store it (such
as direct air or ocean capture, bioenergy with CCS,
or enhanced mineralization). Technologies capable
of carbon dioxide removal are available today, but at
nascent stages and therefore will require additional
research, development, and deployment now through
2050 (more discussion of CDR technologies can be
found in section 6.4).
25
THE LONG-TERM STRATEGY OF THE UNITED STATES
The energy sector is pivotal for
achieving net-zero emissions by 2050.
Achieving net-zero is possible through
a range of pathways, which depend
on how technologies and policies
evolve over the three-decade period.
Nevertheless, by modelling a range of
pathways with plausible assumptions
for this evolution (see Figure 4), we
can distinguish broad trends and
important drivers of the energy sector
transformation.
CHAPTER 4:
TRANSFORMING THE ENERGY
SYSTEM THROUGH 2050
Figure 4: U.S. Energy CO
2
Emissions to
2050 by Economic Sector. Electricity CO
2
emissions and direct CO
2
emissions from the
transportation, buildings, and industry fall
dramatically in all scenarios, with the greatest
reductions coming from electricity, followed
by transportation, and non-land sink carbon
dioxide removals (CDR) increase. Notes:
Historical data are from EIA Monthly Energy
Reviews, projections include data from all LTS
scenarios using both GCAM and OP-NEMS,
projections are shown in ten-year time steps.
0.0
1.0
2.0
2005 2020 2050
Energy Emissions (Gigatons CO
2
)
Transportation
Buildings
Industry
Electricity
CDR
26
THE LONG-TERM STRATEGY OF THE UNITED STATES
4.1 ELECTRICITY
The United States has set a goal for 100% carbon
pollution-free electricity by 2035, and this goal will
provide an important foundation for the Long-Term
Strategy of the United States. Electricity is used in
every economic sector, and all 2050 net-zero pathways
depend on rapidly decarbonizing electricity and
expanding the use of this decarbonized electricity into
as many uses as possible to displace polluting fuels.
The electricity sector, which contributes about a quarter
of all U.S. GHG emissions, has been reducing CO
2
emissions for years, with major shifts caused in part
by increases in renewables and decreases in coal-fired
generation (see Figure 5). Continued cost reductions
in generation and storage are expected to enable even
more rapid reductions of emissions from this sector.
New policies, incentives, market reforms, and other
actions will be needed to ensure that electricity sector
emissions continue to decrease as total electricity
demand increases.
The electricity sector will continue to evolve rapidly as
it decarbonizes. Expected continued cost reductions
in renewable generation as well as battery and other
storage technologies could see emissions decreases of
Figure 5: U.S. Electricity Generation 2005-2050. Generation by source in trillion kilowatt-hours.
Total generation expands to 2050 due to increased use of clean electricity in new applications in
transportation, industry, and buildings. Renewable generation increases rapidly to keep pace with
growing electricity demand and ensure that the share of renewables continues to expand to 2050.
Note: Historical data are from EIA Monthly Energy Reviews, projections include data from all LTS
scenarios using both GCAM and OP-NEMS, projections are shown in ten-year time steps.
0.0
2.0
4.0
6.0
2005 2020 2050
Electricity Generation (Trillion kWh)
Fossil w/ CCS
Fossil w/o CCS
Nuclear
Renewables
Non-Fossil Combustion
Biomass w/ CCS
27
THE LONG-TERM STRATEGY OF THE UNITED STATES
roughly 70-90% by 2030 on a path toward the 2035
100% clean electricity goal. As shown in Figure 5, solar
and wind generation continues to increase substantially
through 2050, while existing nuclear generation
remains in operation and could see growth in the
2030s and 2040s. Unabated fossil generation (coal
or gas generation without CCS technology) declines,
and existing fossil fueled plants start to be fitted with
carbon capture. By 2050, clean generation provides
zero emission electricity to the rest of the economy,
with all electricity providing 15-42% of primary energy.
Recent analyses suggest that wholesale electricity
prices, on average, are unlikely to change significantly
as we shift to a cleaner grid by 2030, with price impact
estimates ranging from a 4% decrease to a 3% increase
[39]. Additionally, the transition to clean electricity is
expected to reduce exposure of U.S. consumers to fuel
supply shocks [40].
Investment in clean energy generation must continue
through mid-century as overall electricity generation
increases to meet demand growth from other sectors.
Average annual total capacity additions without storage
from 2021 to 2030 range from 58 gigawatts per year
(GW/yr.) to 115 GW/yr.; in 2031 to 2040 they range
from 54 GW/yr. to 167 GW/yr.; and in 2041 to 2050
they range from 67 GW/yr. to 123 GW/yr. Storage
capacity additions from 2021 to 2030 average 0.4 GW/
yr. to 2.7 GW/yr.; in 2031 to 2040, they range from 3
GW/yr. to 40 GW/yr.; and in 2041 to 2050 they range
from 11 GW/yr. to 64 GW/yr.
This rapid evolution and scale of change in the
electricity sector is ambitious, with high and sustained
deployment of new technologies through mid-century.
Many significant challenges and barriers exist [14] [22].
The electricity transition will require adding significant
amounts of new zero-carbon electricity capacity at a
sucient pace to replace uncontrolled fossil fuel-fired
generation while also providing ample clean supply for
a growing economy with increased electrification. New
transmission, distribution, and storage infrastructure
will be needed to maintain and improve grid reliability,
including adapting the electric grid to be flexible to
changing supply and demand over all increments of
time. In particular, longer-duration storage solutions
and appropriate incentive mechanisms will be critical.
Absent new action, supply chains may become stressed
by limited availability of raw materials (such as rare
earth elements), manufacturing capacity, and skilled
workforce. Some pathways may also require significant
expansion of carbon capture and storage technologies
during the overall transition, which bring specific
challenges around technology development and siting.
These challenges are substantial but can be addressed
through an integrated strategy of investment,
innovation, and new technology deployment. Large-
scale deployment of renewables can be accelerated
by investments in grid infrastructure and advanced
technologies. Grid infrastructure investments,
including the buildout of new long-distance, high-
voltage transmission projects, can enhance resilience,
improve reliability, better integrate variable generation
resources, lower electricity costs, and unlock the best
clean energy resources by connecting them to demand
centers. Significant deployment of energy eciency
can also help reduce the scale of investment required
by lowering the total energy demand that must be met.
Analyses show that as the sector becomes increasingly
decarbonized, advanced technologies will be brought
online to meet peak load and adjust to seasonal
changes in demand. Advanced technologies—which
could include clean hydrogen combustion or fuel cells,
enhanced geothermal systems, long-duration energy
storage, advanced nuclear, and fossil generation
with CCS—can provide clean firm resources that can
balance increased variable generation. However, these
technologies require a rapid, sustained acceleration
in research, development, and deployment. The
significant investments in generation and transmission
will underpin job growth across the nation, creating
opportunities in cities and rural areas alike, particularly
when paired with workforce training. Expansion
of the transmission system, stronger interregional
coordination, and distributed generation also provide
resilience to natural disasters, saving lives and
protecting businesses.
28
THE LONG-TERM STRATEGY OF THE UNITED STATES
RAPID
DECARBONIZATION
IN THE U.S.
ELECTRICITY SECTOR
IS UNDERWAY
The electricity sector in the United States has been
decarbonizing rapidly, with significant increases in
renewable deployment in recent years.
The shift to lower-emissions sources has been under way for decades, with early contributions from nuclear and then fossil
gas. More recently, since around 2010, federal investment policies, tax credits, and regulatory actions, as well as state
policies, research and development, and market trends, drove significant renewable deployment. At the same time, between
2010 and 2019, more than 546 coal-fired power units retired, totaling 102 GW of capacity, with another 17 GW of capacity
planned for retirement by 2025 [41]. This has led to a dramatic shift in the sources of U.S. electricity, with renewables now
accounting for more generation than coal (Figure 6). In addition, the sum of coal and natural gas generation has also declined
in the last decade, pointing to the important role of renewable energy.
One of the challenges to reach the 2050 net-zero goal (as well as the 2035 100% clean electricity goal) is the large amount
of new zero-emission capacity (primarily renewables) that will need to be deployed annually to enable an increasingly large
share of clean electricity generation. Figure 7 shows some indicative estimates of the magnitude of the annual capacity
additions needed to remain on pace toward our goals, in comparison to recent historical levels of capacity additions. Recent
trends in renewable deployment are encouraging. Solar and wind capacity additions were about 32 GW in 2020, the highest
on record, and are expected to be about 28 GW in 2021. Acceleration will be needed but the deployment rate has been
growing quickly.
28
THE LONG-TERM STRATEGY OF THE UNITED STATES
29
THE LONG-TERM STRATEGY OF THE UNITED STATESTHE LONG-TERM STRATEGY OF THE UNITED STATES
29
Figure 6: Annual U.S. Electricity Generation from All Sectors 1950-2020 (trillion kilowatt-hours). The electricity sector
has been rapidly decarbonizing since 2008. This figure shows electricity net generation in all sectors (electric power,
industrial, commercial, and residential) and includes both utility-scale and small-scale solar. Rapid increases in solar, wind,
and other renewable generation means that in 2020, for the first time, renewable generation surpassed coal generation.
Coal generation has declined rapidly, replaced by natural gas and renewables. Source: EIA [42].
Figure 7: Electric Generation Capacity Additions 2000-2050. Renewable capacity additions have been growing rapidly in
the past decade (left) and are more closely approaching levels that will be needed to sustain the overall decarbonization
trend in electricity needed to reach the 2050 goal. A representative pathway (center) shows deployment of total zero-
carbon technologies roughly on the order of 60–70 GW per year. Diverse scenarios in this analysis show a range of
potential pathways to achieve net zero (right). Note: Historical data are from EIA Monthly Energy Reviews, projections
include data from all LTS scenarios using GCAM. Other scenarios not shown in the figure have cumulative nuclear capacity
additions ranging up to 90–100 GW through 2050.
Source
(percentage of
2020 total)
Natural Gas (40%)
Renewables (21%)
Nuclear (20%)
Coal (19%)
Other (<1%)
0.0
0.5
1.0
1.5
2.0
1950 1960 1970 1980 1990 2000 2010 2020
Electricity Generation (Trillion kWh)
0
10
20
30
40
50
60
70
80
2021-2050
Average
2021-2030 2031-2040 2041-2050
0
10
20
30
40
50
60
70
80
2000 2010 2020
0
10
20
30
40
50
60
70
80
0.
05
Other
Nuclear
Solar
Wind
Fossil w/ CCS
Fossil w/o CCS
New Installed Capacity (Gigawatts per year)
New Installed Capacity (Gigawatts per year)
HISTORICAL CAPACITY ADDITIONS
REPRESENTATIVE PATHWAY TO 2050 NET-ZERO ALTERNATE PATHWAYS TO 2050 NET-ZERO
30
THE LONG-TERM STRATEGY OF THE UNITED STATES
The United States will continue to increase the use
of electricity and sustainably produced low-carbon
fuels in the transportation sector while shifting away
from fossil sources (Figure 8). Over time, electricity,
carbon beneficial biofuels, and hydrogen will become
increasingly clean. The availability and adoption of
these low-carbon fuels in the coming decades will
largely depend on the economics of production and/
or procurement, the competitiveness of bioenergy
and hydrogen compared to alternative low-carbon
technologies across sectors, policy support, private
4.2 TRANSPORTATION
The transportation sector provides vital mobility
services for people and goods with on-road vehicles,
planes, trains, ships, public transportation, and a wide
variety of other modes. It is currently the highest
emitting sector, representing 29% of all U.S. emissions
[27]. To reduce emissions to net-zero by 2050 we will
need to ensure that zero-emission vehicles dominate
new sales for most types of vehicles by the early 2030s,
as well as infrastructure to support alternate modes of
transportation, such as trains, bikes, and public transit.
Figure 8: U.S. Transportation Final Energy Use
2005-2050. Overall transportation energy
in exajoules (EJ) decreases while the use of
electricity and alternative fuels, including
biomass-derived fuels and hydrogen, increases
to power nearly the full U.S. transport system
by 2050. While light-duty vehicles are almost
all electric by 2050 in most scenarios, there
is uncertainty in other transportation sectors.
Uncertainties in the future share of low-carbon
bioenergy vs. hydrogen makes can aect the
potential for electrification in the sector. These
results show end use consumption instead
of service demand (e.g., per mile travelled),
so electricity demand appears smaller than
alternative fuels demand due to the major
inherent eciency advantages of electric
vehicles. Note: Historical data are from EIA
Monthly Energy Reviews, projections include
data from all LTS scenarios using both GCAM
and OP-NEMS, projections are shown in ten-year
time steps.
0
10
20
30
2005 2020 2050
Transportation Energy (Exajoules)
Alternative Fuels
Electricity
Fossil
31
THE LONG-TERM STRATEGY OF THE UNITED STATES
An integrated strategy to address these substantial
challenges can help accelerate the development and
rapid expansion of new transportation technologies.
An expanded network of public transit options and
infrastructure will increase urban mobility, helping
to reduce emissions and increase equity in mobility.
Electrifying segments of the rail system will decarbonize
the existing rail system with the added benefit of
enabling a more robust electric grid along railroad “right
of way.” Additionally, “vehicle to grid” innovations may
provide support for grid services. Accelerated research,
development, demonstration, and deployment of lower-
carbon fuels, such as clean hydrogen and sustainable
biofuels, will contribute to the decarbonization of
applications that may be more dicult to electrify
including aviation and marine transportation and some
medium- and heavy-duty trucking segments.
4.3 BUILDINGS
Buildings house our population and provide a working
environment for commercial sectors including oces,
colleges and K-12 schools, restaurants, grocery stores,
and retail shops. Homes and commercial buildings
are responsible for over one-third of CO
2
emissions
from the U.S. energy system. Of this, roughly two-
thirds of buildings sector emissions currently come
from electricity, with the remainder coming from
direct combustion of gas, oil, and other fuels for space
heating, water heating, cooking, and other services, and
buildings currently account for about three quarters of
U.S. electricity sales [43]. Electricity is used in buildings
for lighting, space heating and cooling, water heating,
electronics and appliances, and other services. CO
2
emissions from buildings have been falling since 2005,
due to increases in energy eciency, the decarbonization
of the electricity sector, and a modest trend towards the
electrification of end uses. These emissions reductions
have been achieved even as commercial building
square footage has increased by more than 25% and
the population has grown by more than 10% since
2005. All buildings need to be decarbonized with an
emphasis on strategies that deliver for overburdened and
underserved communities. For example, in the residential
sector, households with an annual income below
investment and, in the case of bio-based energy, the
ability to minimize potential negative land carbon
outcomes and other environmental impacts of biomass
production. Although demand for transportation
services increases through mid-century, the total
energy consumed in this sector declines due to a
combination of regulations and technological advances
which drive eciency improvements and deliver
societal and consumer benefits.
A central component of the U.S. Long-Term Strategy
in transportation is the expanded use of new
transportation technologies—including a rapid
expansion of zero-emission vehicles—in as many
applications as possible across light-, medium-,
and heavy-duty applications. Already, the growing
popularity of electric vehicles (EVs), supported
by incentives and continued advances in battery
technology, is spurring greater EV adoption and
industry goals for even higher EV sales. Other
technologies can serve as important complements
to EVs. The President’s goal and associated policies
to ensure half of all new vehicles sold in 2030 zero-
emissions vehicles (including battery electric, plug-
in hybrid electric, or fuel cell electric vehicles) will
continue to spur growth across all zero-emission vehicle
types.
This rapid deployment of zero-emissions vehicles
is ambitious and will need to occur at a large scale
across all vehicle types. Many challenges and barriers
exist [14] [22] [25]. For example, costs for electric
technologies, fueling, and charging infrastructure
remain high in some applications. Some transportation
segments, such as aviation, will likely remain dicult to
electrify and some legacy vehicles will continue to be
necessary in the near term, both of which would require
alternate sources of low-carbon fuels that have yet to
be deployed at the necessary scale. The existing built
environment creates also high dependency on owner-
occupied vehicles and presents numerous obstacles to
alternate mobility options and shifting between modes
such as transit, biking, or walking.
32
THE LONG-TERM STRATEGY OF THE UNITED STATES
electrification. Heat pumps and other electric heaters
and electric cooking account for more than 60% of
sales by 2030 and nearly 100% of sales by 2050.
Energy demand in buildings is reduced by 9% in 2030
and 30% in 2050.
While recent trends are encouraging, the building
sector presents some unique challenges to rapid
decarbonization. Foremost is the often-long lifetime
of buildings. Many buildings built today will still be in
active use by 2050, which means that even immediate
actions to improve new buildings take years before
making a significant impact in the overall building stock.
These factors aect all aspects of buildings including
the outer shell; heating, ventilation, and air conditioning
systems; and appliances and lighting—although some
of these are more amenable to retrofitting than others.
In addition, energy eciency and ecient electrification
have barriers relating to their upfront cost structure,
financing, competing landlord and tenant incentives.
These issues can be particularly dicult in underserved
$60,000 account for nearly 50% of all household
energy consumption, making it essential that eorts to
decarbonize buildings are accessible to all households
[44].
The key driver of reducing building emissions is
ecient use of electricity for end uses (such as
heating, hot water, cooking, and others). Alongside
the decarbonization of electricity, these changes can
bring building sector emissions to near-zero by 2050.
Across multiple possible pathways, building eciency
improvements also reduce the overall demand for
energy by the sector, despite the substantial growth
in the number of buildings, floorspace, and population
expected through 2050 (Figure 9). Within this overall
decrease in energy demand, the share of electricity in
final energy demand grows as end uses are electrified,
from about 50% in 2020 to 90% or more by 2050
because the on-site combustion of gas, oil, and other
fuels decreases substantially; however, the growth is
also limited through energy eciency and ecient
Figure 9: U.S. Buildings Site Energy 2005-
2050. Overall building site energy use in
exajoules (EJ) decreases at the same time
as certain applications (e.g., heating) switch
from fossil fuels (and some biomass) to clean
electricity. Note: Historical data are from EIA
Monthly Energy Reviews, projections include
data from all LTS scenarios using both GCAM
and OP-NEMS.
Electricity
Fossil
0
5
10
15
2005 2020 2050
Buildings Energy (Exajoules)
33
THE LONG-TERM STRATEGY OF THE UNITED STATES
conditions, improving health and safety. The role of state
utility regulators will be especially important, as approval
of new rate structures and consumer incentive programs
will be vital in realizing the full potential of consumer
benefits. Finally, building improvements will come from
manufacturing, construction, and installation performed
by skilled, well-paid American workers in communities
across the country.
4.4. INDUSTRY
The U.S. industrial sector, currently produces roughly
23% of U.S. GHG emissions and 30% of emissions
from the energy system [45]. It is heterogeneous,
producing a wide range of products with diverse and
sometimes specialized processes. The energy-intensive
and emissions-intensive industries include mining,
steel manufacturing, cement production, and chemical
production, and collectively produce nearly half of overall
industrial emissions. In addition to the CO
2
emissions
resulting from industrial demand for electricity, the
industrial sector emits GHGs directly from many
operations and processes including the use of fossil fuels
for onsite energy use and as feedstocks, direct process
emissions of CO
2
from cement production and other
industries, and emission of non-CO
2
GHGs such as N
2
O
from nitric and adipic acid production.
Although there are many hard-to-decarbonize elements
of industrial activities, investments in technologies
for advanced non-carbon fuels, energy eciency, and
electrification can reduce overall industrial sector
CO
2
emissions by 69-95% by 2050. A large range of
potential pathways for the industrial sector are shown
in Figure 10. Overall energy use drops in most scenarios
through energy eciency and materials eciency
investments. In these scenarios, overall electricity use
in the sector grows only slightly due to electrification.
However, in scenarios that rely on a large quantity
of hydrogen, electricity use increases dramatically
to produce the hydrogen through electrolysis. In all
scenarios, low-carbon fuels (including electricity) grow
as a percentage of total energy use.
communities, which will also need widespread access to
retrofits and new building technologies, though innovative
financing tools such as inclusive investment programs can
deliver substantial benefits to these communities while
reducing or eliminating financing barriers and ensuring
consumer protections.
To address these challenges, pursuing multiple options
eectively help achieve the necessary rapid emissions
reductions in buildings while also reducing the energy
cost burden for families and businesses and improving
the health and resilience of communities. There are three
important sources of emissions reductions: technological
advances including from envelope improvements (e.g.,
attic and wall insulation, sealing leaks, and ecient
windows), improved eciency of electric end uses (e.g.,
lighting, refrigeration, appliances, and electronics), and
the ecient electrification of space and water heating,
cooking, and clothes drying in both existing and new
buildings. The rapid deployment of heat pumps for
space heating and cooling and water heating is the
central strategy for the ecient, flexible electrification
of buildings. By increasing the amount of demand-
responsive heating, cooling, and water heating on the grid,
these technologies can respond to shifts in renewable
generation levels on short notice and reduce the overall
cost of a low- or zero-carbon generation mix.
Ecient and electrified buildings provide substantial
consumer benefits. The most important benefit is reduced
utility bills for households and businesses which are
both direct (through lower energy usage) and indirect
(through lower energy prices). More ecient buildings
significantly reduces electricity demand and lessen winter
peaking loads as the sector electrifies, reducing the cost
of new generation, transmission, and distribution, which
in turn reduces energy prices for American families and
businesses. These bill savings would be most beneficial to
low-income households, which typically face the greatest
energy burden. Buildings can also support electric vehicle
charging infrastructure and rooftop solar installations,
key elements of the broader energy transition. More
ecient buildings also retain indoor temperature for
longer during power outages under extreme weather
34
THE LONG-TERM STRATEGY OF THE UNITED STATES
the specific needs of each subsector. Key strategies include
energy eciency, material eciency, electrification,
adoption of low-carbon fuels and feedstocks, and CCS.
Energy eciency, waste heat recovery, and accelerated
adoption of advanced technologies such as additive
manufacturing, can significantly reduce energy demand
and lower costs to businesses. Material eciency
incorporates structural changes in manufacturing that
include product recycling and reuse, material substitution,
and demand reduction. Electrification of heated, fuel-
consuming industrial processes and equipment is a viable
pathway for some subsectors, such as light industry.
Low-carbon fuels and feedstocks, including clean hydrogen
and low-carbon biofuels, can reduce emissions from
processes that are dicult to electrify. Finally, CCS can be
used for emissions that are hard to abate through other
means, particularly in the cement, chemicals, and iron
and steel industries. Increased investments in research,
development, demonstration, and deployment will advance
technologies in production of iron and steel, cement,
chemicals, and other industries, enabling these sectors to
adopt low-carbon production.
Reducing energy-related GHG emissions from industry
presents a set of unique challenges [14] [22] [26]. A
primary feature of this sector is that it is diverse: unlike
electricity or buildings, for example, whose emissions
come from a relatively small set of activities, industrial
activities and infrastructure are designed around a large
set of processes. Some of these processes might have
relatively straightforward substitutes, but in other cases
either those substitutes may not exist yet or might be
higher cost. In some cases, alternate sources of process
heating may need to be identified. In other cases, CCS
applications may be needed but these may be expensive
or infeasible at existing production facilities. At the
same time, scaling up of material eciency could be
challenging because of product design limitations or
consumer demand. Many of these challenges also
aect the non-CO
2
emissions from industry, which are
discussed further in Chapter 5.
In response to these challenges, the industrial energy
transition can be enabled to decarbonize at a suciently
rapid pace through a diverse set of approaches tailored to
Figure 10: Industry Final Energy Use 2005-2050.
Overall industrial energy use in exajoules (EJ)
decreases to 2050 while certain applications
switch from fossil fuels to clean electricity,
hydrogen, or biofuels. Electricity use increases
further in scenarios with larger hydrogen
production due to the high electricity demand for
that pro-cess. In this analysis, CCS in deployed in
industry for process emissions, but there is limited
representation of CCS on industrial energy in
the models we use. Accordingly, it is likely that a
greater share of industrial fossil energy emissions
could be captured by 2050 than is shown here.
Note: Historical data are from EIA Monthly
Energy Reviews, projections include data from all
LTS scenarios using both GCAM and OP-NEMS,
projections are shown in ten-year time steps.
0
5
10
15
20
2005 2020 2050
Industry Energy (Exajoules)
Fossil w/o CCS
Fossil w/ CCS
Electricity
Biomass w/o CCS
Biomass w/ CCS
Hydrogen
35
THE LONG-TERM STRATEGY OF THE UNITED STATES
5.1 INTRODUCTION
Non-CO
2
GHGs make up 20% of the U.S. contributions
to global warming [27]. Non-CO
2
GHGs are highly
potent heat trapping gases, many of which have greater
near-term climate impacts than CO
2
[36]. As shown in
Figure 11, three gases make up the majority of non-CO
2
GHG emissions in the United States: methane (CH
4
),
nitrous oxides (N
2
O), and fluorinated gases (including
HFCs) [27]. The three sources that produce the
largest proportion of emissions are soil management
(i.e. agriculture and land use), livestock, and energy.
While mitigation opportunities exist for many sources
of non-CO
2
GHG emissions, costs and applicability
vary. Because it is challenging to eliminate all of these
sources, some remaining non-CO
2
emissions will need
to be oset in 2050 by net-negative CO
2
emissions.
This analysis estimates that the total technical potential
for non-CO
2
GHG mitigation across all sectors is
approximately 35% without reducing the underlying
activities [36]. Reducing the use of fossil fuels through
eciency and fuel switching also has the potential
to further drive down non-CO
2
GHG emissions by
19% given the relationship between fugitive methane
CHAPTER 5:
REDUCING NON-CO
2
EMISSIONS
THROUGH 2050
Figure 11: Sources of U.S. Non-CO
2
GHG Emissions, 2019.
Contribution to 2019 U.S. GHG emissions from non-CO
2
sources partitioned by type and sector. The contributions are
shown in CO
2
equivalent, meaning that they are represented
in proportion to their global warming contribution 100 years
after emission. Approximately half of the global warming
contribution of non-CO
2
gases in 2019 came from methane,
with nitrous oxide contributing the second most, followed by
fluorinated gases.
36
THE LONG-TERM STRATEGY OF THE UNITED STATES
development of new or more eective mitigation
technologies and approaches. In addition, in a way that
is similar to the industrial energy emissions described in
Chapter 4, the sources of non-CO
2
emissions are diverse.
This means that individual strategies must be developed
for each sub-sector and gas.
In light of these challenges, this LTS analysis of non-
CO
2
GHG mitigation potential assumes only modest
technological and cost improvements over time. Because
these assumptions may be conservative, additional,
lower-cost, and more rapid reductions could be realized,
and this will remain an area of active inquiry. Achieving
more significant long-term reductions of non-CO
2
GHG
emissions will require major technological advances
and new, or more eective, backstop mitigation options.
In sectors with less developed current approaches,
this could include new research and development into
identifying and commercializing new technologies
to reduce non-CO
2
emissions. In other sectors, new
emissions from the extraction, processing, and end-
use of fossil fuels. These reflect multiple technological
options that United States can use to achieve the
necessary reductions in non-CO
2
GHG emissions to
reach net-zero total emissions by 2050 (Figure 12).
Under these scenario assumptions, there remain non-
CO
2
GHG emissions in the 2030 and 2050 timeframes,
which must be oset by carbon dioxide removal.
Reductions in non-CO
2
emissions face several
challenges. First is an underdeveloped set of mitigation
strategies in certain subsectors. In part because of
a lack of historical focus on non-CO
2
reductions, the
set of available mitigation approaches for these gases
is still relatively small and, in many cases, in earlier
stages of technological development. This means
that through 2050, overall non-CO
2
emissions can be
held roughly constant by deploying currently available
mitigation technologies. Achieving long-term reductions
of non-CO
2
emissions below current levels requires
Figure 12: Pathways for Non-CO
2
Reductions from 2020 to 2050.
This figure shows the range of pathways available for non-CO
2
mitigation from today
to 2050 across all modeled scenarios. In all scenarios there is significant reduction
from the 2020 reference, highlighting the importance of non-CO
2
abatement.
Methane
Nitrous Oxide
Fluorinated gases
0
200
400
600
2005 2020 2050
Non-CO
2
emissions (Million metric tons CO
2
equivalent)
37
THE LONG-TERM STRATEGY OF THE UNITED STATES
gas, such as some of the methane and N
2
O from
the agriculture sector, cannot be abated in the 2050
timeframe even after applying all available mitigation
technologies, and will have to be oset by negative CO
2
emissions.
5.2.1 METHANE
Methane is a potent GHG and accounts for about half of
the current observed warming
5
of 1.0°C, according to the
latest report of the Intergovernmental Panel on Climate
5
Greenhouse gas emissions in total have contributed 150% of the observed
warming of 1.0⁰C, but emissions of cooling aerosols have counter-acted
some of that warming.
mitigation options are under development and nearing
commercialization that could result in large volumes
of non-CO
2
mitigation and further reduce non-CO
2
emissions (see Box 4).
5.2 KEY ABATEMENT OPPORTUNITIES
Potential reductions in non-CO
2
gases can come from
a diverse set of actions, and these actions together
aggregate to significant levels (Figure 13). Technical
potential includes technologies like anaerobic digestion
of manure in the agricultural sector and leakage
detection and mitigation in the oil and gas sector.
As discussed above, some portion of each non-CO
2
Figure 13: Non-CO
2
Mitigation Technical Potential by Gas (MtCO
2
e) in 2050.
This figure shows potential reductions in 2050 from non-CO
2
emissions in methane,
nitrous oxide, and fluorinated GHGs. It is constructed from abatement cost curves using
technologies like anaerobic digestion of manure in the agricultural sector and leakage
detection and mitigation in the oil and gas sector. Some abatement technologies are negative
cost and many cost less than $100 per metric ton of CO
2
e. Technical abatement potential is
most significant for methane and fluorinated gases.
Residual
Mitigation <$100
Residual
Mitigation <$100
Residual
Mitigation <$100
Mitigation >$100
Mitigation >$100
Mitigation >$100
0
200
400
600
800
Methane Nitrous oxide Fluorinated gases
Mitigation Technical Potential (MtCO
2
equivalent)
38
THE LONG-TERM STRATEGY OF THE UNITED STATES
and natural gas typically fall into three categories:
equipment modifications or upgrades; changes in
operational practices, including directed inspection,
repair and maintenance (DI&M); and installation
of new equipment [35]. Abatement measures
are available to mitigate emissions associated
with a variety of system components, including
compressors, engines, dehydrators, pneumatic
controls, pipelines, storage tanks, wells, and others.
Commercially-available mitigation technologies can
also recover and reduce CH
4
emissions from coal
mining operations. These reduction technologies
consist of one or more of the following primary
components: a drainage and recovery system to
Change [1]. Methane is primarily generated by fossil
fuel energy operations (oil, gas, and coal), waste
operations, and livestock and agricultural operations.
There are cost eective methane abatement options
across all these sectors [36]. Figure 14 shows 2050
methane abatement potential by source.
Methane mitigation opportunities by sector include:
• ENERGY SECTOR METHANE. Energy sector fugitive
methane emissions result from operations in the oil
and natural gas sector and the coal mining sector.
In some cases, a large proportion of oil and gas
methane emissions come from a small number
of sources. Methane mitigation measures in oil
Figure 14: 2050 Methane Abatement Potential in the United States.
This figure shows sources of methane abatement potential in 2030 in the United
States [36]. This marginal abatement cost curve indicates the price at which
methane mitigation from various sources of methane are cost-eective. This
figure does not include additional abatement that can be achieved by reducing the
underlying activities that drive emissions. These additional reductions from activity
driver changes are included in the GCAM modeling and reflected in Figure 12.
0
50
100
150
0 100 200 300
Methane Emissions Reductions (MtCO
2
e)
Break-even Price ($/tCO
2
e)
Coal Mining
Croplands
Landfills
Livestock
Oil and Natural Gas
Rice
Wastewater
39
THE LONG-TERM STRATEGY OF THE UNITED STATES
remove CH
4
from the underground coal seam, an
end use application for the gas recovered from the
drainage system, and/or a ventilation air methane
(VAM) recovery or mitigation system [35]. The
CH
4
mitigation potential from the energy sector at
$100/tCO
2
e is 144 million metric tons of carbon
dioxide equivalent (MtCO
2
e) or approximately 43%
of 2030 energy sector non-CO
2
GHG emissions
and remains an important source of potential
mitigation through 2050.
• WASTE METHANE. Landfills produce CH
4
and
other landfill gases through the natural process of
bacterial decomposition of organic waste under
anaerobic conditions. Landfill gases are generated
over a period of several decades, with flows usually
beginning within 2 years of disposal. Abatement
options to control landfill emissions are grouped
into three categories: (1) collection and flaring,
(2) landfill gas (LFG) utilization systems, and
(3) enhanced waste diversion practices (e.g.,
recycling and reuse programs) [35]. Within the
waste category, wastewater treatment is the
second most important source of non-CO
2
GHGs.
Methane emissions in wastewater treatment could
be significantly reduced by 2050 through currently
available mitigation options, such as anaerobic
biomass digesters and centralized wastewater
treatment facilities. Improved operational practices,
such as controlling dissolved oxygen levels during
treatment or limiting operating system upsets, can
also help reduce N
2
O emissions from wastewater
treatment [35]. The CH
4
mitigation potential
from the waste sector non-CO
2
GHG at $100/t
is 8 MtCO
2
e or 6% of total 2030 waste sector
emissions and remains an important source of
potential mitigation through 2050.
• LIVESTOCK METHANE. Emissions from livestock
include enteric fermentation and manure
management. Enteric fermentation is a normal
mammalian digestive process, where gut microbes
produce CH
4
. Livestock manure management
produces CH
4
emissions during the anaerobic
GLOBAL
METHANE
PLEDGE
In September 2021 at the Major Economies Forum, the
United States and European Union jointly announced
the Global Methane Pledge. As of October 2021,
over 30 supportive countries, representing well over
30% of global methane emissions and 60% of global
GDP, had already joined—with many more expected.
Countries joining the Global Methane Pledge commit to
a collective goal of reducing global methane emissions
by at least 30% from 2020 levels by 2030. They also
commit to moving towards using highest-tier inventory
methodologies to quantify methane emissions, with a
particular focus on high emission sources.
Delivering on the Pledge would reduce warming by at
least 0.2°C by 2050. In addition, it would prevent over
200,000 premature deaths, hundreds of thousands
of asthma-related emergency room visits, and over 20
million tons of crop losses a year by 2030 by reducing
ground-level ozone pollution caused in part by methane.
The United States is pursuing significant methane
reductions on multiple fronts. The Long-Term Strategy
analysis shows that the United States can do its part
to meet the global goal of the Global Methane Pledge
by reducing domestic methane emissions by over
30% below 2020 by 2030. This level of reduction
would avoid 11,000 premature deaths, 1,600 asthma-
related emergency room visits, and 4.1 million tons of
agricultural losses per year in the United States.
40
THE LONG-TERM STRATEGY OF THE UNITED STATES
Nitrous oxide mitigation opportunities by sector
include:
• AGRICULTURAL NITROUS OXIDE. Agriculture is the
source of over 82% of nitrous oxide emissions.
Most N
2
O is produced in soils by bacteria through
the processes of nitrification and denitrification
which occur with fertilizer application. It is also
emitted in lesser amounts from livestock waste,
rice production, and soil management such as
draining, irrigation, and land use change. Nitrous
oxide emissions can be mitigated by changing
fertilizer management practices to increase the
eciency of plant uptake of nitrogen [35]. Practices
include precision agriculture, using nitrification
inhibitors, and splitting annual applications into
seasonal applications. The mitigation potential from
the agriculture sector at $100/t is 8.8 MtCO
2
e,
which is 2.5% of 2030 nitrous oxide emissions
from agriculture [36] and remains a small source of
mitigation through 2050.
• NITRIC AND ADIPIC ACID PRODUCTION.
Nitric acid is an inorganic compound used primarily
to make synthetic commercial fertilizer. Adipic
acid is a white crystalline solid used as a feedstock
in the manufacture of synthetic fibers, coatings,
plastics, urethane foams, elastomers, and synthetic
lubricants. The production of these acids results
in nitrous oxide emissions as a by-product. By
2030, about two-thirds of nitrous oxide emissions
from this source category are projected to be from
adipic acid production driven by high demand
growth compared with about one-third from nitric
acid production. Abatement measures applicable
to nitric acid are characterized by the point in the
production process they are implemented, but
generally involve catalytic decomposition of the
nitrous oxide by-products [35]. Thermal destruction
is the abatement option applied to the adipic acid
production process. The mitigation potential from
nitric and adipic acid production at $100/t is 17.7
MtCO
2
e or 62% of total sectoral 2030 nitrous
oxide emissions [36] and remains an important
source of mitigation through 2050.
decomposition of manure and N
2
O emissions
during the nitrification and denitrification of the
organic nitrogen content in livestock manure and
urine [35]. Without altering underlying demand,
the mitigation potential of livestock methane at
$100/t is 70 MtCO
2
e or 27% of 2030 livestock
non-CO
2
GHG emissions and remains an
important source of potential mitigation through
2050.
• CROPLAND AND RICE PRODUCTION METHANE.
The anaerobic decomposition of organic matter
(i.e., decomposition in the absence of free
oxygen) in flooded rice fields produces CH
4
.
GHG mitigation scenarios include several factors
that influence the amount of CH
4
produced and
carbon sequestration in soils, including water
management practices and the quantity of
organic material available to decompose [35]. The
mitigation potential from the agriculture sector at
$100/t is 1.7 MtCO
2
e or 1% of 2030 agricultural
CH
4
emissions [36].
5.2.2 NITROUS OXIDE
Nitrous oxide (N
2
O) is a potent GHG with 298
times more warming potential than carbon dioxide
and a long atmospheric lifetime (approximately 114
years). N
2
O comes from natural and anthropogenic
sources and is removed from the atmosphere
mainly by photolysis (i.e., breakdown by sunlight)
in the stratosphere. In the United States, the main
anthropogenic sources of N
2
O are agricultural soil
management, livestock waste management, mobile
and stationary fossil fuel combustion, adipic acid
production, and nitric acid production. N
2
O is also
produced naturally from a variety of biological sources
in soil and water, although this report only covers
man-made sources only. Figure 15 shows 2050
nitrous oxide abatement potential by source.
41
THE LONG-TERM STRATEGY OF THE UNITED STATES
to replace ozone-depleting substances (ODS) in
refrigeration, air conditioning, aerosols, fire suppression,
and as foam blowing agents. HFC emissions reductions
are achievable by preventing or reducing leaks and
transitioning to the use of alternatives with low global
warming potential (GWP). Figure 16 shows 2050
fluorinated GHG abatement potential by source.
Under the American Innovation and Manufacturing
(AIM) Act of 2020, in September 2021 the EPA
finalized a rule that phases down HFCs through an
allowance allocation and trading program. The AIM
5.2.3 FLUORINATED GASES
Fluorinated gases (F-GHGs) are anthropogenically-
generated and used in a range of applications.
Sometimes referred to as “climate superpollutants,”
they are highly potent GHGs, capable of trapping
hundreds to thousands of times more heat per
molecule than carbon dioxide. According to the
2021 Inventory of U.S. Greenhouse Gas Emissions
and Sinks [27], most fluorinated gases emitted are
hydrofluorocarbons (HFCs). A substitute for ozone-
depleting substances, HFCs were initially developed
Figure 15: 2050 Nitrous Oxide Abatement Potential in the United States.
This figure shows sources of nitrous oxide abatement potential in 2050 in the
United States. This marginal abatement cost curve indicates the price at which
nitrous oxide mitigation from various sources of are cost-eective. This figure
does not include abatement associated with a reduction of the underlying
activities that drive emissions. These additional reductions from activity driver
changes are included in the GCAM modeling and reflected in Figure 11.
0
50
100
150
0 10 20 30 40 50
N
2
O Emissions Reductions (MtCO
2
e)
Break-even Price ($/tCO
2
e)
Livestock
Nitric Adipic
Rice
Croplands
42
THE LONG-TERM STRATEGY OF THE UNITED STATES
5.2.4 BLACK CARBON
Black carbon (soot) is not a GHG, but a powerful
climate-warming aerosol [1] that is a component of fine
particulate matter (PM
2.5
) that enters the atmosphere
through the incomplete combustion of fossil fuels,
biofuels, and biomass [46]. The Arctic is particularly
vulnerable to warming from black carbon. Black carbon
is also a local air pollutant, contributing to major health
impacts that disproportionately aect low-income and
marginalized communities [47]. Transitioning from
fossil fuel combustion for electricity and transport
(on-road and o-road) to cleaner alternatives is key to
reducing black carbon emissions in the United States.
Flaring in the oil and gas sector is an additional source
of black carbon. The EPA estimates that U.S. black
carbon emissions have been reduced significantly since
2013 primarily due to reductions in the road and o-
road transport sectors, largely through policies and
strategies to reduce the emissions from mobile diesel
engines. Strengthening particulate matter standards
and addressing legacy diesel vehicles and emissions
associated with ports, including from ships, port
equipment, and trucks, would further contribute to
meeting national climate, health, and climate justice
goals.
Act, along with this rule, provides the domestic legal
framework to implement the phasedown of HFCs
outlined in the Kigali Amendment to the Montreal
Protocol, which 124 countries have joined to date. The
phasedown will eectively decrease the production and
import of HFCs in the United States by 85% by 2036 on
the same step-down schedule as laid out in the Kigali
Amendment and is expected to result in reductions of
more than 4.5 billion metric tons of carbon dioxide-
equivalent by 2050.
Achieving significant HFC reductions by 2050 will
rely on a three-pronged approach. First, phase down
the production and import of HFCs. Second, address
the existing stock of refrigerators and air conditioners,
which already contain HFCs and have potential to leak
into the atmosphere over the coming decades. Third,
deploy the next generation of low-GWP alternatives
to existing HFCs. Additional RD&D support to ensure
new alternatives to HFCs continue to enter the market
may also be important, including both new molecules
and new uses for existing alternatives. Combining these
approaches, the mitigation potential of HFCs at less
than $100/t is 84 MtCO
2
e which is 39% of total 2030
sectoral emissions and remains an important source of
mitigation through 2050.
43
THE LONG-TERM STRATEGY OF THE UNITED STATES
Figure 16: 2050 Fluorinated GHG Abatement Potential in the United States:
This figure shows sources of fluorinated GHG abatement potential in 2050 in the United
States. This marginal abatement cost curve indicates the price at which F-GHG miti-gation
from sources of are cost-eective. This figure does not include additional abatement that
can be achieved by reducing the underlying activities that drive emissions. These additional
reductions from activity driver changes are included in the GCAM modeling and reflected in
Figure 11.
0
50
100
150
40 80 120 160
F-Gas Emissions Reductions (MtCO
2
e)
Break-even Price ($/tCO
2
e)
Aerosols
Aluminum
Electric Power Systems
Fire Extinguishers
Foams
Magnesium
Photovolatics
Refrigeration and AC
Semiconductors
Solvents
44
THE LONG-TERM STRATEGY OF THE UNITED STATES
NON-CO
2
BREAKTHROUGH
TECHNOLOGIES:
REDUCING METHANE
FROM ENTERIC FERMENTATION
While many low-cost abatement opportunities exist
today for non-CO
2
emissions—and are reflected in
this analysis—some specific applications do not
have current, low-cost mitigation opportunities.
A renewed focus on research and development for these
remaining non-CO
2
emission processes could potentially
provide significant benefits as well as dramatically lower the
costs of reductions. While not required to achieve our 2050
net-zero goal, such advances could provide valuable additional
flexibility in how that goal could be achieved.
One example of this kind of positive breakthrough may be
emerging. Without a technological advance, there is limited
methane abatement potential from enteric sources—cattle,
sheep, and goats—which produce methane as part of their
digestive process. While improving productivity can, to a
limited extent, help reduce methane emissions per pound
of beef or gallon of milk, it does not provide a route to
major reductions. However, recent research suggests that
new technologies might be able to offer greatly increased
effectiveness. New discoveries of low-cost feed additives
indicate the possibility that these would unlock large
additional potential emissions reductions. Examples of these
additives include red algae (Asparagopsis) and a compound,
3-Nitrooxypropanol (3-NOP).
EPA and other researchers are collecting information to
assess these technologies. Asparagopsis, 3-NOP, and other
technologies that may increase non-CO
2
GHG mitigation. The
science and economics of Asparagopsis is far from settled,
with important remaining questions surrounding the costs to
grow, harvest, and process Asparagopsis into feed, to assess
scalability to produce marketable quantities (or directly
synthesize bromoform); and to assess the long-term tolerance
of cattle and the applicability to different production and
regulatory systems. If national-scale developments prove
technically and economically feasible, Asparagopsis could
potentially decrease livestock emissions by as much as 160
MtCO
2
e (60%) in 2030. 3-NOP has shown strong potential for
methane reduction across multiple trials, with over 45 peer-
reviewed papers examining numerous aspects of the potential
impacts of this additive. 3-NOP has been shown to be effective
in reducing enteric emissions by about one-third in dairy cows
and up to 70% in beef finishing trials without unacceptable
side-effects. More innovation and testing are needed to further
develop these solutions and bring them to market.
THE LONG-TERM STRATEGY OF THE UNITED STATES
44
45
THE LONG-TERM STRATEGY OF THE UNITED STATES
6.1 THE NECESSITY OF
CO
2
REMOVAL TO REACH
NET-ZERO
Eciency, electrification of end uses,
decarbonization of the electricity
sector, and reduction in non-CO
2
emissions are the most important
levers for decarbonizing the U.S.
economy and will be the emphasis of
the overall strategy to reach net-zero
by 2050.
CHAPTER 6:
REMOVING CARBON THROUGH
2050 AND BEYOND
Figure 17: Balancing Emissions Reductions
and Removals to Reach 2050 Net-Zero.
This figure shows the range of outcomes
for mitigation pathways as well as removals
pathways to achieve net-zero by 2050.
Some sources of non-CO
2
emissions, and
potentially some CO
2
emissions, cannot be
reduced to zero, and these must be balanced
by CO
2
removals. CO
2
removals can happen
through land sinks, such as forest growth
and soil carbon sequestration, or through
carbon dioxide removal technologies such
as direct air capture or carbon capture
and sequestration in industry or electricity
generation. Note: Historical data in this figure
are from the U.S. GHG Inventory (2021).
0.0
2.5
5.0
2005 2020 2050
Net Emissions (Gigatons CO
2
e)
CO2
Non-CO2
Land Sink
CDR
Net-GHG
46
THE LONG-TERM STRATEGY OF THE UNITED STATES
Though the overall U.S. lands net carbon sink has been
relatively stable for recent decades, the future of that
sink is uncertain [50], and several challenges exist to
bolstering it and expanding it significantly. Substantial
forested lands, including large portions of our Western
public lands, now have older forests which sequester
less CO
2
and are more vulnerable to natural disturbances
[51]. Moreover, increased levels of disturbances—fires,
insects, diseases, droughts, and storms—are expected
in the future, along with other potential ecosystem
changes such as CO
2
fertilization, due to climate change.
These changing environmental conditions will also
dictate the future degree of mitigation and adaptation
capabilities and opportunities [53]. These factors are
already having an impact: total carbon removal in the
land use, land use change, and forestry (LULUCF) sector
has decreased by approximately 11% since 1990 [27]. In
addition, U.S. lands include diverse ecosystems which
complicates eorts at comprehensive and timely data
collection, as well as monitoring and verification of
baseline emissions, sequestration, and GHG outcomes
of mitigation activities. In addition, the land base is
finite in terms of its ability to continue to provide food,
fiber, and essential ecosystem and biodiversity services
while also supporting potentially increased levels of
carbon-beneficial biomass for energy production and
carbon removal strategies through bioenergy and
CCS. In addition, CO
2
removals via natural systems
can be more variable than those in other sectors or
technologies, as they are subject to reversals, e.g., from
natural disturbances like fires, storms, and pests or
from individual landowners changing land management
practices. Also, with respect to policies, U.S. lands are
held and managed for dierent objectives by a range
of dierent stake-holders that operate under dierent
legal, social, and environmental norms. Achieving land
sector goals necessitates coordination and cooperation
with millions of private landowners, private sector
corporations, and non-governmental organizations,
as well as Tribal, local, state, and federal government
agencies.
These challenges may be counterbalanced, at least in
part, by changes in the economy, policy actions, and
investments. Achieving significant land carbon benefits
However, as mentioned in previous sections, some
activities will be dicult to decarbonize completely
by 2050. Because of this, removals of CO
2
from the
atmosphere will be critical to enable the United States
to reach net-zero by 2050 and to achieve net negative
emissions thereafter. This implies an important role
for the land sector, which can increase natural carbon
dioxide removal and storage from the atmosphere,
as well as a role for technologies including advanced
carbon dioxide removal (CDR) technologies. Carbon
dioxide removal technologies will only deliver desired
societal and environmental benefits if their deployment
is well-designed and well-governed. Figure 17 shows
the range of outcomes for mitigation pathways as well
as removals pathways to achieve net-zero by 2050.
6.2 MAINTAINING AND ENHANCING CO
2
REMOVAL THROUGH THE U.S. LAND
CARBON SINK
U.S. lands provide myriad social, economic, and
environmental benefits. The United States has 8% of
the world’s forests (310 million ha) and 8% of global
agricultural lands (400 million ha) [48]. These lands
provide essential ecological, economic, and non-
monetary social services, and will also be critical in
supporting economy-wide decarbonization over the
next 30 years and beyond.
Our lands, and human activities on those lands, emit
CO
2
to the atmosphere through land conversion, soil
degradation, and forest loss and degradation, but also
remove it via photosynthesis and store it as carbon
in trees, other vegetation, soils, and products. For the
last several decades, U.S. lands have been a net carbon
sink, meaning more CO
2
is sequestered than emitted
annually from the land sector. This historic trend was
due in part to millions of acres shifting into forest
from other uses and the conservation and continued
regrowth of trees on already forested lands, much of
which had been deforested before the early 1900s [49].
Today’s forest sink is still increasing but at a decreasing
rate [27]. In 2019, the U.S. land carbon sink yielded net
CO
2
removals of 813 MtCO
2
e, osetting approximately
12.4% of economy-wide GHG emissions [27].
47
THE LONG-TERM STRATEGY OF THE UNITED STATES
• AGRICULTURAL LANDS. There are potential
substantial GHG mitigation and increased removal
opportunities on U.S. croplands and grasslands
via activities that conserve and/or increase soil
carbon and employ innovative lands management
approaches such as agroforestry, rotational grazing,
reduced tillage, residue management, and more.
• BIOENERGY. Biomass is a key component of eorts
to decarbonize the energy sector, as studies have
shown that higher levels of biomass availability
and use can oer lower-cost mitigation than
decarbonization strategies without biomass (e.g.,
[60] [61]). Bioenergy can be particularly useful in
deep decarbonization scenarios, as it can be used to
decarbonize energy use in multiple sectors through
a range of dierent energy pathways (e.g., liquid
fuel, biogas, electricity, and hydrogen production)
and it can be used in combination with CCS to
further reduce GHG emissions [9]. Eorts aimed at
employing biomass use for energy should include
safeguards to ensure actual emissions reductions
to the atmosphere and reflect consideration of the
many non-carbon consequences of large-scale
biomass production and use (e.g., competition
with food production and biodiversity and broader
ecosystem impacts).
6.3 ASSESSING POTENTIAL LAND SECTOR
PATHWAYS
The LTS pathways explored for this study include
varying degrees of private and public investment
in natural climate solutions in both forestry and
agriculture, such as improved forest management,
fire reduction activities, aorestation, and improved
agricultural soil management. To better reflect the
uncertainties associated with estimating the complex
carbon dynamics of dierent terrestrial ecosystems and
related market interactions, and the potential extent
of land use change between sectors, the U.S. LULUCF
projections through 2050 are presented as a range,
as seen in Figure 18. This range was developed via a
collaborative multi-agency eort using dierent models
reflecting alternate modeling techniques.
by 2050 and beyond requires targeted, science-based
action in the near term and over the next several
decades. These actions must not only work to enhance
our land carbon sink but also ensure our lands continue
to provide a host of other benefits, including provision
of goods, jobs, ecosystem services, recreational and
spiritual spaces, and biodiversity preservation. For
example, public and private investments in natural
climate solutions (e.g., augmented federal programs,
private entities’ involvement in land conservation and
oset markets) can increase acreage, productivity,
and overall health of U.S. forested lands [52] [54].
Strengthening existing and supporting new emerging
timber markets, especially in the fast-growing climes
of Southeast United States, can also help maintain and
expand forested lands [55]. Policies, incentives, and
investments that can support an enhanced sink through
activities such as reforestation and soil carbon retention
will be central. Low- or zero-carbon biomass for
bioenergy and BECCS applications can also contribute to
emissions reductions. These policies and programs must
include safeguards to minimize issues such as potential
reversals and leakage to the extent possible, and include
eorts to bolster our ability to monitor, track, and verify
emissions reductions at dierent scales.
Specific areas of focus include:
• FORESTS. GHG benefits in the relative near term can
come from activities such as avoided forest land
conversion to other uses. Some forest sector actions,
such as longer harvest rotations or increased carbon
storage in harvested wood products and substitution
of more fossil-intensive construction materials with
wood products, can yield both near- and long-term
benefits [56]. There are considerable opportunities
for reforestation in the United States [57], potentially
up to 133 million acres [58]. Other activities like
aorestation, improved forest management and
reduced natural disturbances (e.g., avoided forest
fires via fuel treatments such as thinning and
prescribed fires) can oer incremental near-term net
carbon benefits and may yield substantial benefits in
the long term [59].
48
THE LONG-TERM STRATEGY OF THE UNITED STATES
6.4 CO
2
REMOVAL THROUGH ENGINEERED
APPROACHES
In addition to the land sector CO
2
reduction potential,
technological CO
2
removal options could be deployed
over coming decades to support the net-zero emissions
goal. While some technologies for such activities do
exist, advanced CDR technologies are today in various
stages of development.
At this early stage, it is dicult to estimate exactly
which combinations of technologies might be most
achievable and appropriate in terms of deployment, but
potential strategies include:
The analysis is based on several sectoral lands models
including the Global Timber Model (GTM), the Forestry
and Agriculture Sectoral Optimization Model with
Greenhouse Gases (FASOM-GHG), three U.S. Forest
Service models (the Resources Planning Act (RPA)
Forest Dynamics model, the RPA Land Use Change
model, and the Forest Resource Outlook model), and
USDA agricultural soil carbon projections, to provide
a range of potential land sink projections in 2050.
As shown in Figure 18, there is a significant range of
possible land sector pathways which could enable the
United States to meet its net-zero goal by 2050.
Figure 18: Land Use, Land Use Change, and Forestry CO
2
Business as Usual and LTS Action
Projections with Uncertainty Ranges. There is a range of possible CO
2
outcomes for both
the reference case and the Long-Term Strategy action case. Historic values are from the U.S.
GHG Inventory [27] and projected values are derived from a range of land sector models.
Estimates include forest ecosystem carbon pools, harvested wood products carbon storage,
and land use and land use conversion fluxes across land types.
BAU Range
NCS Action Range
-1,500
-1,000
-500
0
2005 2020 2030 2040 2050
LULUCF Sink (Mt CO
2
equivalent)
49
THE LONG-TERM STRATEGY OF THE UNITED STATES
but the potential capacity of CO
2
mineralization
could be quite high [62].
• OCEAN-BASED CDR.
This is a CDR approach that removes dissolved CO
2
from the ocean. Ocean-based approaches include
nature-based approaches (e.g., kelp aorestation),
engineered approaches (e.g., electrochemical CO
2
capture from seawater), or a combination of the
two (e.g., growing macroalgae and sinking it to the
sea floor). Ocean-based CDR is in early stages of
research and development and merits closer study.
The early stages of these potential removal strategies
present some visible challenges to large scale
deployment by 2050. For example, there is currently
no large-scale proof of concept for DAC technology
or bioenergy with carbon capture and storage, making
it dicult to determine how well the technology can
scale up and what the true cost and adverse impacts
of the technology are at large scale. In parallel, some
technical obstacles remain. Research to date indicates
that DAC requires high energy use for each metric ton
of CO
2
removed. Other technologies, such as enhanced
mineralization, are still in nascent stages of research and
development, so the potential magnitude of reductions
and the timeframes over which these technologies might
deliver reductions is unknown. Other uncertainties
associated with large-scale deployment of some
technologies like BECCS could have broader upstream
GHG and other environmental implications (e.g., life-
cycle GHG outcomes of biomass production).
Addressing these challenges and uncertainties
will require a substantial and integrated research,
development, and deployment strategy. As one step
towards the development and deployment of new
approaches to CDR, Congress recently created the
Carbon Dioxide Removal Task Force to “establish a
research, development, and demonstration program…to
test, validate, or improve technologies and strategies to
remove carbon dioxide from the atmosphere on a large
scale” [63]. However, additional actions will be needed
to understand and innovate on CDR options, to reduce
uncertainties, and to ensure sustainable outcomes.
• BIOMASS CARBON REMOVAL AND STORAGE.
This is a carbon dioxide removal approach where
CO
2
is produced from the combustion, gasification,
or other conversion of low- or zero-carbon biomass,
for example to generate electricity or produce
hydrogen, and the resulting CO
2
emissions are
captured and then stored in a manner that prevents
it from reentering the atmosphere. Specifically,
the captured CO
2
emissions are compressed into
a fluid and transported to a specified site, where
they are injected into deep, underground geological
formations, such as former oil and gas reservoirs or
deep saline formations for long-term storage. CDR
eorts using biomass as an input, such as biomass
use for energy with CCS, should include safeguards
to ensure actual emissions reductions to the
atmosphere (e.g., including, to the extent possible,
robust GHG accounting), and reflect consideration
of the many non-carbon consequences of large-
scale biomass production and use (e.g., competition
with food production and biodiversity and broader
ecosystem impacts) [61].
• DIRECT AIR CAPTURE AND STORAGE (DACS).
This is a technology that captures CO
2
emissions
directly from ambient air (instead of from point
sources, such as power plants or industrial facilities),
via solvent, solid sorbent, or mineral processes.
The captured CO
2
is then either compressed and
sequestered permanently in a geological setting or
converted into a usable material such as a synthetic
aggregate in concrete production.
• ENHANCED MINERALIZATION.
This is a CDR approach that accelerates natural
geologic processes around mineral reactions with
CO
2
from the ambient air, leading to permanent
carbon storage through carbonate rock. There are
several types of mineralization processes: in situ (e.g.,
CO
2
reactions in geologic formations underground),
ex situ (e.g., CO
2
reactions that involve extraction,
transport, and grinding of minerals), and surficial
(e.g., ambient weathering using CO
2
-enriched fluids
and on-site minerals like mine tailings). Research and
development for enhanced mineralization is still early,
50
THE LONG-TERM STRATEGY OF THE UNITED STATES
7.1 THE BENEFITS FROM A TRANSFORMED,
NET-ZERO ECONOMY
Bold and timely climate action towards net-zero
will help the United States and the world avoid the
worst impacts of climate change—and provide a
transformative boost to the U.S. economy and the
health and well-being of all Americans. Reductions
in fossil fuel combustion and reductions in non-CO
2
emissions will improve air quality and reduce the
dangerous risks of climate change. The expansion of
new industries will create high-quality jobs, maintain
economic competitiveness, and enable sustainable,
broad-based economic growth. The benefits from this
transformation are not constrained by political borders:
U.S. action and ambitious action from other countries
will have positive spillover eects including driving
down the cost of carbon-free technologies and reducing
the costs of climate induced disasters and conflicts
around the world, particularly for lowest-income
nations that are least able to adapt.
In addition to the economic gains, action to meet the
net-zero goal will, combined with global eorts, allow
the United States to avoid the worst impacts of climate
change, which are already being felt. For example, air
pollution kills thousands of people in the United States
annually [64] and millions worldwide, particularly in
the lowest-income countries, and ongoing international
conflicts are exacerbated by climate change [65].
The longer action is delayed, the faster the transition
must be, potentially causing severe disruption [66].
Moreover, delay incurs more severe consequences such
as changed weather regimes (including new extremes
[67]), higher sea level rise, greater ocean acidification
[68], and a higher likelihood of reaching catastrophic
damages or “tipping points” and potentially irreversible
ecological impacts. These impacts have health and
economic costs for all, but they are borne unequally,
with greater consequences for low-income countries
globally and communities of color, low-income
communities, and indigenous communities within the
United States [69]. For example, Black children are
34-41% more likely to live in areas with the highest
projected increases in asthma diagnoses due to
climate-driven changes in particulate air pollution [68].
These impacts are addressed more completely in the
National Climate Strategy [2].
CHAPTER 7:
BENEFITS OF CLIMATE ACTION
THROUGH 2050
51
THE LONG-TERM STRATEGY OF THE UNITED STATES
7.2 IMPROVEMENTS IN PUBLIC HEALTH
Climate-driven changes in weather, human activity, and
natural emissions are all expected to impact future air
quality across the United States [70]. Acting now on
climate change and decarbonizing our energy sector
will result in vastly cleaner air, immediate and long-term
improvements in public health, and ecological benefits
throughout the United States. These benefits arise from
several sources.
REDUCING GHGS CAUSES REDUCTION IN POLLUTANTS
HARMFUL TO HEALTH, WELL-BEING, AND PRODUCTIVITY.
Reducing GHGs to net-zero by 2050 will
simultaneously reduce other pollutants, including
particulate matter (PM), ozone and PM precursors,
nitrous oxides (NO
x
), sulfur dioxide (SO
2
), and other
air toxics. These benefits will be more significant in
communities overburdened by air pollution. Ozone
and PM are air pollutants that adversely aect human
health and are monitored and regulated with national
standards [71]. Human exposures to these pollutants
have been associated with premature death, hospital
admissions, and respiratory ailments, among others.
A total of 60,600 deaths in the United States in 2019
alone were attributable to PM and ozone exposure [73].
The energy sector accounts for 80% of emissions of
NO
x
and 96% of SO
2
[70]. As the economy transitions
to carbon-free energy, reductions in air pollution are
also expected to increase productivity of the workforce
due to health improvements. Beyond the traditional
focus on mortality impacts, there is emerging evidence
that minor health impacts from air pollutants can also
adversely aect educational attainment and reduce
labor productivity, e.g., fewer tasks completed and
fewer hours worked [74]. Such improvements would be
important because climate projections show a direct
impact of future extreme temperatures reducing hours
worked in the economy [75].
REDUCING CLIMATE CHANGE SEVERITY SAVES LIVES
AND IMPROVES HEALTH. Climate change threatens
the health and well-being of Americans through
catastrophic events; increases in heat-related illnesses
and deaths; increases in vector-, food-, and water-borne
disease; and reduced food and water quality. In addition
to immediate fatalities associated with the events
themselves, extreme weather events can exacerbate
underlying medical conditions and disrupt critical health
care, resulting in potentially lasting consequences.
Furthermore, temperature increases have been linked
to increases in premature death due to exposures to
both cold and heat extremes; additionally heat exposure
has led to increases in emergency room visits and
hospital admissions for heat-related illnesses such as
cardiovascular and respiratory conditions, kidney failure,
and preterm birth, among others [77]. There are large
disparities in urban heat environments in many U.S. cities
that put lower-income people and people of color at
higher risk of heat exposure [79]. Changes in temperature
and rainfall patterns have been implicated in the spread
of some infectious diseases in some areas, including
mosquito-borne Zika and West Nile viruses, by creating
conditions that promote the expansion, abundance, and
activity of certain disease vectors [76] [78]. Waterborne
diseases have been associated with excessive rainfall as
well as drought conditions. Water temperature increases
have contributed to the growth of toxic algal blooms and
harmful pathogens (e.g., Salmonella and Campylobacter),
the presence of which can adversely aect food
security and availability [77]. As for air pollution, the
benefits of action to reduce impacts will be strongest
in communities that are historically disadvantaged,
low-income, and/or lack access to health services and
prevention and are therefore most vulnerable to climate
change [68]. For example, Hispanic and Latino individuals
are 25-43% more likely to currently live in areas with the
highest projected labor hour losses in weather-exposed
industries due to increases in high-temperature days.
7.3 AVOIDING COSTLY CLIMATE IMPACTS
Avoiding climate change will provide immediate and
sustained benefits to the economy across several
categories. Global emissions reductions can substantially
reduce the damages of climate change in the United
States [80]. One estimate shows reduced monetary
damages from a subset of climate change impacts of
$49 billion/year in 2050 and up to $388 billion/year in
52
THE LONG-TERM STRATEGY OF THE UNITED STATES
2090 to the U.S. economy in 1.5°C-
compatible scenarios compared to
a reference scenario, from factors
such as fewer deaths, less damage
to infrastructure, and fewer lost
wages.
6
Similarly, Figure 19 shows
the large and increasing benefits
that accrue over time to the overall
economy from a low-emissions
pathway.
7
This analysis is only a
lower bound estimate as it does not
include a comprehensive accounting
of all potential impacts such as other
health eects, eects on managed and
unmanaged ecosystems, some indirect
eects, and social impacts.
6
The temperature and radiative forcing for the two scenarios are
calculated from the median over an ensemble of 600 MAGICC v7.5.1
runs selected to match assessed proxy ranges [112]. For the 1.5°C
scenario, global mean temperature reaches 1.5°C in 2100 with a
corresponding radiative forcing of 2.45 Wm
-2
and 3.8°C in 2100 with a
corresponding radiative forcing of 7.60 Wm
-2
for the Reference scenario.
Descriptions of future population, GDP, the transformation of global
temperature change to continental U.S. temperature change, estimation
of sea level rise, and other parameters and assumptions can be found in
[111]. This framework includes impact estimates that employ a variety
of assumptions regarding adaptive responses to climate impacts. The
general adaptation scenarios considered in the analyses do not capture
the complex issues that drive adaptation decision-making at regional
and local scales. Adaptation and scenario assumptions used in this
analysis: High Tide Flooding and Trac impacts assume reasonably
anticipated adaptation measures; Rail, Roads, Electricity Transmission
and Distribution Infrastructure, and Coastal Properties assume reactive
adaptation; Extreme Temperature Mortality assumes cities in cooler
climates will adapt and become more resilient similar to present day
cities in warm climates; and Ozone and PM
2.5
Mortality uses 2011
emissions of co-emitted pollutants. The rest of the sectors do not
explicitly model adaptation.
7
Damages, and therefore avoided damages, increase over time due to
the increasing divergence in global mean temperature change between
the two scenarios along with growing populations; more valuable
potentially vulnerable infrastructure; and higher valuation of avoided
mortality.
Figure 19: Projected Annual Benefits of Climate Mitigation for
Select Years. Benefits from keeping to a 1.5⁰C trajectory grow
significantly over time. U.S. annual economic impacts for a subset
of sectors for the Reference minus 1.5°C scenario
8
. Impacts
presented in billions of $2017.
8
17 U.S. sectors are represented in this figure. Health impacts consist
of the following sectors: extreme temperature mortality, ozone and
PM
2.5
mortality, valley fever, wildfire health eects, and suppression and
southwest dust health eects. Coastal impacts consist of the following
sectors: coastal property, hightide flooding and trac, and tropical
storm wind damages. Infrastructure consists of the following sectors:
rail and road infrastructure, electricity demand and supply, electricity
transmission and distribution, and urban drainage. Water resources
consist of the following sectors: water quality, winter recreation, and
inland flooding. Lastly, the labor sector represents lost wages.
0
100
200
300
400
2050 2070 2090
Annual Benefits of Climate Mitigation (Billion 2017$ US)
Water Resources
Labor
Coastal
Infrastructure
Health Impacts
53
THE LONG-TERM STRATEGY OF THE UNITED STATES
7.4 ENHANCED CLIMATE SECURITY
There is a growing body of evidence that climate change
can exacerbate conflict and reduce global security.
Climate change is a national security threat because
it is globally destabilizing, changes military operating
conditions, and demands new missions [81]. This
means that mitigating the risk of climate change not
only delivers ecological, public health, and economic
benefits, but also enhances national and global security.
By acting early and leading by example, the United
States can build confidence in global eorts to reduce
the risk of climate change [82]. The risks of a changing
climate can make existing conflict more violent, lead to
instability, and, through more erratic weather, aect the
ability of the military to respond to security concerns.
The U.S. National Intelligence Estimate assessment
is that “climate change will increasingly exacerbate
risks to U.S. national security interests as the physical
impacts increase and geopolitical tensions mount about
how to respond to the challenge” [83].
Extreme weather and conditions increasingly
attributed to climate change already impact U.S.
infrastructure, through the eects of sea level rise,
storms, and wildfire. The U.S. Department of Defense
calls climate change a “top management challenge”
because of the threat to operational security and to
the physical infrastructure of installations [84], and
finds that climate change is reshaping the geostrategic,
operational, and tactical environments with significant
implications for U.S. national security and defense [6]. It
can also impact military readiness by diverting military
assets and personnel to assist with disaster recovery,
storms, and wildfire impact [85].
Experts agree that climate-related events (droughts,
storms, wildfires, and flooding) are already contributing
to conflict [86]. While the main conflict drivers have
been related to low socioeconomic development,
low state capability, intergroup inequality, and a
history of conflict, these drivers can be exacerbated
by disruption related to climate change [87]. Clear
causal relationships between climate change and
specific conflicts are the subject of ongoing research,
but drought, floods, and other disasters related to
climate change have been associated with large-scale
displacement of people and, in some cases, this has led
to political instability and conflict.
Climate change is related to both short-term
phenomena such as extreme weather events and
long-term impacts such as rising sea levels and
persistent drought. All of these can aect the lives
and potentially the movements of large numbers of
people in a way that can increase stresses within
and between countries. Tropical storms, which are
expected to become more severe as climate continues
to change (and have already become more severe in the
Atlantic Basin), already can displace large populations.
Hurricane Katrina, for example, traumatically displaced
tens of thousands of people from the city of New
Orleans. In a country with lower capacity to address
such crises, a similar event could create climate
refugees and cause instability. Continued, more
frequent, or more severe drought is also an expected
result of climate change. In agricultural societies,
severe drought can exacerbate stresses. Drought
contributed to the current civil war in Syria, causing
internal destabilization as well as political stresses in
neighboring countries due to the resulting refugee crisis
[88]. The impacts of long-term changing sea level have
already led to climate refugees, including in parishes
in southern Louisiana [89]—and this can be disruptive
across the world. For example, a further sea level rise of
six inches (15 cm) could displace millions from the Nile
Delta in Egypt [90]. Instability in strategically important
regions, even far from the United States, is a national
security concern.
Societies can respond to crises like drought and water
stress by strengthening political relationships that
can benefit mutual security [91], but, in particular for
vulnerable societies, the impacts of climate change may
result in increased conflict. Actively working to mitigate
climate change along with helping communities to
build resilience and adapt may reduce the risks of these
conflicts.
54
THE LONG-TERM STRATEGY OF THE UNITED STATES
7.5 BUILDING A STRONGER U.S. ECONOMY
The revolution in climate solutions has already begun.
The fastest-growing power generation technologies
are solar and wind, with a record-setting 35 GW of
deployment in 2020, accounting for about 80% of new
capacity [92]. Globally, the zero-emissions vehicle share
of new car sales is expected to rise from 2% today to
nearly 30% by 2030 [93], with significantly higher
numbers in the United States in line with reaching
50% new car sales. In these and many other sectors,
the transition to carbon neutrality will accelerate for
compatibility with international climate targets [94],
representing rapidly expanding new markets in the
United States and globally.
The economic opportunity of decarbonization is
immense. The United States is well-positioned to
incubate new innovators and firms, with a well-trained
workforce and institutions that have enabled global
leaders in information technology, biotechnology,
pharmaceuticals, and other industries [95]. Moreover,
a unique endowment of natural resources makes
geographic regions of the country well-suited to be
hubs of a wide range of carbon-free activities [40]. The
United States can lead in the clean technologies for
the 21
st
century, manufacturing crucial technologies
like batteries, electric vehicles, and heat pumps,
without sacrificing critical worker protections or a fair
distribution of benefits of economic activity.
Because innovation is cumulative and because many
environmental technologies have returns to scale,
investing early in the development of new technologies
[96] will boost innovation in climate solutions and make
the pathway to carbon neutrality more economically
and politically feasible [97] [98]. Smart public
investments in innovation stimulate private investment
and economic growth and can help establish new (and
often unforeseen) productive industries in the process
[99] [100] [101]. One recent study finds social returns
from investments in research and development are as
much as four times larger than private returns [102],
and an analysis of data on 16 advanced countries
between 1980 and 1998 found that a 1% increase
in public research and development investment
generated an extra 0.17% in long-run output [103]. The
benefits of accelerating innovation will spill over to our
international partners, including to developing countries
which will be hit hardest by climate damages and can
least aord to take actions in response.
Although the overall economy will benefit from the
transition to carbon neutrality, certain fossil fuel-
dependent sectors and regions will have a more
dicult transition. Some communities are already
experiencing economic challenges from the declines
in fossil fuel-related employment [104], while others
(predominantly low-income communities, communities
of color, and indigenous communities) are experiencing
disproportionate impacts of climate disasters and air
pollution. A comprehensive policy strategy can support
American workers and firms through the transition,
creating high-quality jobs throughout the country,
including in historically marginalized communities and
in regions that have lost major employers and taxpayers.
The United States can lead in clean technologies and jobs
for the 21
st
century and is well-positioned to incubate new
and innovative firms.
55
THE LONG-TERM STRATEGY OF THE UNITED STATES
With our ambitious NDC target to cut emissions in half
or more by 2030, and our goal for net-zero emissions
no later than 2050, the United States has committed to
sustained investment in a vibrant clean economy that
will propel global climate action while improving social,
economic, and health equity at home.
This report has presented the U.S. Long-Term Strategy
to achieve these ambitious goals. The road ahead
to 2050 contains opportunities, uncertainties, and
challenges. The opportunities are clear and broad
ranging, and collectively oer a pathway to reinventing
and reinvigorating the American economy to be
equitable, globally competitive, and supportive of
global climate and sustainability goals. It will rely on
American innovation and partnerships across all of
society, including Tribal and subnational governments;
private sector businesses, industry, and investors; non-
governmental organizations and cultural institutions;
universities, research organizations, and educational
institutions; and our people. Together, we can meet
the challenges in developing and deploying new clean
technologies at scale. We can discover new and
creative ways to provide better services and products
with lower climate footprints. And we can develop,
train, and educate workers for productive and healthier
work in new and fast-growing industries. Undoubtedly,
the U.S. roadmap will evolve as we learn more about the
potential for new technologies in diverse applications,
and as new policy platforms are developed over time.
The United States intends to regularly review and
update this Long-Term Strategy as needed to consider
such developments and the latest science.
Given the rapid pace of action in the United States
and other leading countries, if other major economies
adopt similar levels of ambition, the world can keep a
safer 1.5°C future within reach. For its part, the United
States currently emits 11% of annual global GHGs
(second to China, which emits 27% of the global total),
so eliminating U.S. emissions by 2050 will make an
important direct contribution to reaching our shared
global climate goals. However, others must step up with
both long-term and short-term ambition, and many
are already doing so. To date, at least 63 countries
representing over half current global emissions have
committed to net-zero GHG emissions targets. Many
more, representing over 70% of global emissions, are in
CHAPTER 8:
ACCELERATING GLOBAL
CLIMATE PROGRESS
56
THE LONG-TERM STRATEGY OF THE UNITED STATES
diverse stages of identifying and committing to similar
net-zero targets by mid-century [105] [106] [107].
These commitments matter: achieving near-net-zero
emissions globally by 2050 will dramatically improve
our chances of limiting global warming to near 1.5°C.
However, while the rapid expansion of 2050 targets
and long-term strategies is encouraging, commitments
to act by 2030 are also critical. Countries representing
well over half of the global economy, including nearly
all the G7 countries, have already put forward strong
2030 NDCs. Leadership and action by these countries
will support development of new and more aordable
climate technologies and support enhanced diplomatic
momentum to encourage global action toward reaching
sucient levels of near-term action.
But the United States, EU, UK, Japan, Canada,
Republic of Korea, South Africa, and other ambitious
major economies cannot do it alone. Strong 2030
NDCs will be required by all G20 economies to cut
global emissions by at least 40% by 2030. Enhanced
action by all G20 members to adopt high ambition
2030 NDCs and mid-century net-zero commitments
could reduce warming by over 0.5°C and keep 1.5°C
within reach [108]. Globally, this is the moment for all
the world’s major economies to act to rapidly reduce
emissions to meet ambitious 2030 NDC targets and
to develop and communicate strategies to achieve
ambitious 2050 net-zero goals.
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