What the agreement is
The Paris Agreement is an international climate accord adopted in December 2015 and entered into force in November 2016. Nearly every country in the world has joined. Its central goal is to hold the increase in global average temperature to well below 2°C above pre-industrial levels, while pursuing efforts to limit warming to 1.5°C.
Rather than setting binding emission limits, the agreement asks each country to submit its own plan, called a Nationally Determined Contribution, or NDC. Countries are expected to update their NDCs every five years and report on their progress, but there are no penalties for missing targets.
The U.S. on-again, off-again participation
The United States was an original signatory under President Barack Obama in 2016. President Donald Trump announced withdrawal in 2017, and the U.S. formally exited in November 2020. President Joe Biden rejoined the agreement in February 2021. In January 2025, the second Trump administration again initiated withdrawal.
Because the agreement is treated as an executive agreement rather than a Senate-ratified treaty, presidents have been able to enter and exit without congressional action, contributing to the back-and-forth across administrations.
The current U.S. pledge
Under the NDC submitted in 2021, the United States pledged to reduce greenhouse gas emissions 50–52% below 2005 levels by 2030. The target covers carbon dioxide, methane and other heat-trapping gases across the economy, including the power, transportation, industrial and agricultural sectors. Meeting it would require continued shifts in electricity generation, vehicle fleets and industrial processes.
The case for stronger commitments
Supporters of stronger U.S. commitments point to assessments by the Intergovernmental Panel on Climate Change, which find that current global pledges, even if fully met, are not on track to limit warming to 1.5°C. They argue that as the world's largest historical emitter and second-largest current emitter, the U.S. has both capacity and responsibility to lead, and that clean-energy investment can yield long-term economic and public-health benefits.
The case against
Critics argue the agreement places disproportionate costs on the United States while allowing other major emitters more latitude. China, the world's largest current emitter, has pledged only to peak emissions before 2030, and India and other developing economies have similar trajectories. Critics also raise concerns about effects on manufacturing, energy prices and consumer costs, and question whether voluntary international pledges meaningfully change global outcomes.
What is actually being decided
"Strengthening" U.S. commitments could mean tightening the 2030 target, setting a more ambitious 2035 target, expanding international climate finance, or backing the pledge with additional domestic regulation and spending. Because participation itself is now contested, voters weighing this question are often considering both the level of ambition and whether the U.S. should be in the agreement at all.