January 29, 2021
United States Rejoins the Paris Agreement on Climate Change:
Options for Congress
On January 20, 2020, President Joe Biden accepted, on
A Party’s NDC must identify how the Party intends to abate
behalf of the United States, the Paris Agreement (PA), an
its GHG emissions, with a current time horizon of 2030.
international accord to address climate change for decades
(See text box.) Each Party decides its own pledge. All PA
to come. The acceptance takes effect on February 19,
emissions targets are voluntary and nonbinding, although
2021—77 days after the United States’ withdrawal took
the PA contains provisions to encourage their achievement.
effect under the Trump Administration, and exactly four
The UNFCCC requires reporting and review of GHG
years after the United States first became a Party to the PA
emissions sources and sinks and other information,
under the Obama Administration.
differentiated by types of Parties. The PA led to an
enhanced transparency framework applicable to all Parties.
Congress may consider implications of U.S. participation in
The PA contains cooperative compliance mechanisms but
the PA along several dimensions, including foreign policy,
not formal sanctions.
economic, environmental, and legal. Although the President
holds constitutional authority for U.S. foreign policy, the
GHG Pledges in Selected NDCs
Senate may provide advice and consent, should the
(with date of most recent NDC GHG target)
President submit the PA to be a treaty under U.S. law.
Congress, by virtue of its own constitutional authorities, has
United States (2015, prior to withdrawal): Reduce GHG
options for shaping, funding, and conducting oversight of
emissions to 26%-28% below 2005 levels in 2025.
strategies—international and domestic—associated with
China (2015): Inter alia, by 2030, to peak its carbon dioxide
U.S. PA commitments. Congress may seek to consult with
(CO2) emissions; lower its CO2 emissions per unit of gross
the Administration on climate change and foreign policy,
domestic product (GDP) by 60%-65% below 2005 levels; and
among other objectives.
increase the non-fossil-fuel share of energy consumption to
around 20%.
What Is the Paris Agreement?
European Union (2020): A binding net domestic GHG
The PA exists under the United Nations Framework
emission reduction of at least 55% by 2030 compared with 1990.
Convention on Climate Change (UNFCCC). The United
States ratified the UNFCCC in 1992 with the advice and
India (2016): Inter alia, reduce GHG emissions per unit of GDP
consent of the Senate. In 2016, the United States accepted
by 33%-35% by 2030 from the 2005 level and reach 40% of its
the PA without requesting the Senate’s advice and consent;
cumulative instal ed electric capacity from non-fossil-fuel sources
the Department of State took the view that the PA was an
by 2030.
executive agreement containing no substantive, legal
Mexico (2020): Inter alia, reduce GHG emissions by 22% and
obligations for the United States beyond those already
black carbon emissions by 51% by 2030 below a business-as-
required by the UNFCCC. Under President Trump, the
usual (BAU) scenario or reduce GHG emissions up to 36% and
United States withdrew from the PA, citing concerns about
black carbon emissions up to 70% by 2030 below BAU by 2030,
fairness, costs of participating, and sovereignty. U.S.
conditioned on financial, technical, and other support.
private sector and bipartisan support subsequently has
grown for the PA, though there is little consensus on targets
Countries have long negotiated over what would constitute
or policies to meet them.
a “fair” distribution of effort under the UNFCCC. The
Under the UNFCCC, the United States and industrialized
strength of one Party’s GHG target compared with those of
Parties listed in “Annex I” took on specific commitments
other countries can be viewed from various perspectives of
for greenhouse gas (GHG) mitigation, financial resources,
fairness and level of effort. To illustrate, under existing
reporting, and review. The PA does not contain the
NDCs, China’s GHG emissions could grow to 2030,
bifurcation of commitments in the UNFCCC between
whereas the European Union’s (EU’s) GHG emissions
Annex I and developing country Parties. It established a
would fall. Nonetheless, China’s GHG emissions per
single, common set of obligations for all Parties (with
person would remain well below those of the EU (or the
flexibilities for the least capable). For example, China
United States). China’s pledge would reduce its emissions
agreed in the PA to the same binding requirements as the
per unit of GDP more than the United States would under
United States.
its 2015 pledge.
A key requirement of the PA is that all Parties communicate
Foreign Policy and Diplomacy
“Nationally Determined Contributions” (NDC) every five
U.S. forceful negotiation, acceptance, withdrawal, and
years, though the content of an NDC is not binding. Once a
rejoining of the PA leaves legacies that are likely to shape
Party, the United States must submit a new NDC; Pres ident
future diplomacy. Some observers argue variously that the
Biden aims to do this before Earth Day 2021 (April 22).
previous Administration’s withdrawal from the PA (1)
https://crsreports.congress.gov
United States Rejoins the Paris Agreement on Climate Change: Options for Congress
reduced U.S. standing in the world by making the United
climate change would impose on people—costs of adapting
States an international outlier on climate change; (2)
to climate change plus residual losses where anticipatory
strengthened perceptions that the United States was
action does not fully avoid adverse impacts.
withdrawing from its traditional position of leadership in
support of a rules-based international order; (3) created
Trade could be affected by differences in Parties’ policies.
space for China to increase its world leadership on climate
China, South Korea, and European and other countries
change and influence in international organizations and
pursue investment toward low-GHG-emitting technologies
processes; and (4) made the United States appear less
in advanced energy, materials, electronics, vehicles, and
reliable as a negotiating partner.
others they expect to provide future trade advantages.
Several governments and the EU have discussed imposing
Some observers argue that any adverse implications of
border adjustments (i.e., tariffs) on producers that do not
withdrawal were offset by benefits they perceive in avoided
make similarly ambitious efforts to reduce GHG emissions.
domestic costs, increased energy independence, dominance
in global fossil fuel markets, and U.S. sovereignty.
Financial Assistance
As the United States rejoins the PA, it may benefit from the
In the UNFCCC, higher-income Parties committed to
goodwill of those in the international community who
provide financial assistance to lower-income Parties to help
welcome the policy change. President Biden plans to host a
them meet their obligations and GHG targets. The decision
Climate Leaders Summit on Earth Day 2021 to promote
accompanying the PA to implement it extends to 2025 a
greater GHG reduction pledges before the next Conference
nonlegal goal from the 2009 Copenhagen Accord to
of the Parties in early November 2021. He also announced a
mobilize jointly $100 billion per year to address the climate
host of further diplomatic and security initiatives.
finance needs of developing countries. The funds “may
come from a wide variety of sources, public and private,
Observers suggest U.S. withdrawal left a legacy that may
bilateral and multilateral, including alternative sources.”
challenge the United States to regain the confidence of
The U.S. federal government has not provided public funds
others and credibility for its commitments. Various
since FY2016 appropriations, though private sources have
commenters indicate the Biden Administration may need to
contributed billions to climate-related finance. President
significantly increase U.S. ambition to reduce net GHG
Biden has charged the Secretaries of State and the Treasury
emissions; embody steps necessary to achieve U.S. GHG
to lead development of a climate finance plan.
targets in durable regulations and new law; demonstrate
performance in accord with its strategy; and be consistent in
Potential Options for Congress
fulfilling unmet commitments on reporting and financing.
U.S. participation in the PA raises a number of options that
Environmental Considerations
Congress may consider, including
The PA contains a collective commitment to achieve
consultation with the Department of State and/or the
approximately net zero GHG emissions in the second half
White House regarding new U.S. pledges under the
of this century. The President has called for “net-zero
UNFCCC and PA, and fulfilling currently unmet
global emissions by mid-century or before.” The purpose in
commitments on reporting and finance;
the PA is to hold the GHG-induced increase in global
average temperature to well below 2o Celsius and to try to
oversight of Administration uses of existing statutory
limit it to 1.5oC. The pledges made in NDCs to 2030 are
authorities to meet U.S. pledges, and whether there may
intended as near-term steps in a multi-decadal process to
be benefits in a more comprehensive legislated strategy,
avoid adverse impacts on people, economies, and the
to address efficiency and distributional impacts;
environmental systems on which societies depend.
provision of public funds, or incentives for private
Many actions to reduce GHG emissions bring co-benefits—
financing, to assist low-income countries or particularly
positive effects beyond the intended climate change
impacted populations; and/or
benefits. An example is reduced health care costs and
mortality associated with air pollution. In many instances,
requests for assessments from the Administration of the
adopted GHG policies have been estimated to achieve co-
ambitions, relative levels of effort, and performance of
benefits that themselves exceed the costs of the GHG
other Parties’ GHG mitigation, adaptation, technology,
reductions, without counting direct climate change benefits.
and financing associated with the PA.
The degree of co-benefits depends on policy design and
depth of GHG reductions, as well as on the affected sectors.
See also CRS Report R44609, Climate Change: Frequently
Economy and Trade Implications
Ask ed Questions About the 2015 Paris Agreement, by Jane
A. Leggett and Richard K. Lattanzio; CRS In Focus
Parties intended the PA to lay a path to long-term transition
IF10397, International Climate Change Assistance: Budget
of the world’s economies toward “deep decarbonization”—
Authority, FY2009-FY2019, by Richard K. Lattanzio.
sustaining economic growth while delinking it from
emissions of CO2 and other GHGs. Such a transition is
Jane A. Leggett, Specialist in Energy and Environmental
generally expected to impose near- to medium-term costs,
with the magnitude and distribution (e.g., across sectors or
Policy
populations) depending on policy timing and design as well
IF11746
as private investment. Some economists estimate the costs
of deep decarbonization would be less than the costs
https://crsreports.congress.gov
United States Rejoins the Paris Agreement on Climate Change: Options for Congress
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