The United States’ second exit from the Paris Agreement wasn’t unexpected. Even before he was reelected, now-president Donald Trump had promised for months that he would pull the country out of the United Nations pact to limit global warming: the Paris climate “rip-off,” as he called it.
Still, the sound of Trump’s black Sharpie scratching across the signature line of an executive order — “Putting America First In International Environmental Agreements” — seemed to reverberate around the world this week, as climate experts, diplomats, and concerned laypeople watched the world’s largest historical emitter of greenhouse gases turn its back on the accord.
The 2015 Paris Agreement is a treaty signed by 196 countries that agrees to limit global warming to “well below 2 degrees Celsius” (3.6 degrees Fahrenheit), and, ideally, cap temperature increases at 1.5 degrees C (2.7 degrees F). Almost every year since then, countries have gathered annually to hash out the accord’s particularities and — in theory, at least — reach further consensus on how to address climate change. This annual conference, known as the “conference of the parties” or COP, is the main venue at which the United States’ withdrawal will be felt.
Some of the most immediate impacts will be financial. Leaving the Paris Agreement, which will take one year from the day Trump notifies the United Nations of his intention to do so, means the U.S. will no longer contribute to funding streams intended to help poorer countries transition away from fossil fuels and prepare for the impacts of climate change. Trump’s executive order said it “revoked and rescinded” the U.S. International Climate Finance Plan, which laid out a government-wide strategy to scale back public investments in international fossil fuel projects while increasing investments in clean energy and adaptation financing abroad.
In 2024, U.S. Congress appropriated $1 billion for climate mitigation in the developing world, and the country has contributed less than the other nations most responsible for climate change, like Germany and Japan. Although Climate Action Tracker, an independent scientific project run by three research institutions, has rated the U.S.’s contributions to climate finance “critically insufficient,” some experts have raised concerns that the U.S. halting funding altogether could have a chilling effect on contributions from other donor countries.
Even so, U.S. nonparticipation in the Paris Agreement is unlikely to dramatically change the pace of climate progress. That’s due to a couple of ways the treaty is structured. First, the 2015 pact never bound the U.S. to any specific amount of emissions reductions; it just required the U.S. to submit a “nationally determined contribution,” or NDC, every five years. The U.S. has dutifully done so — but not in accordance with the goals set by the agreement’s signatories. Up until former president Joe Biden’s last full month in office — when he pledged to slash greenhouse gas emissions 61 to 66 percent by 2035 — the targets the U.S. submitted were deemed by Climate Action Tracker to be incompatible with the Paris Agreement objective of limiting global warming to 1.5 degrees Celsius.
Sean Gallup / Getty Images
The same is true of every other country that’s a party to the agreement. Not one has set a Paris-aligned emissions reduction target, and the United Nations Environment Programme estimated last October that countries’ collective emissions reduction pledges would allow 2.6 to 3.1 degrees C (4.7 to 5.6 degrees F) of warming by the end of the century. A May 2024 survey of 380 members of the Intergovernmental Panel on Climate Change — the world’s foremost scientific authority on the subject — found that 77 percent believe humanity is headed toward 2.5 degrees C (4.5 degrees F) or more of warming by 2100.
“The global emissions trajectory was already far off track from where the science showed was necessary, before this administration came in,” said Rachel Cleetus, a policy director for the nonprofit Union of Concerned Scientists.
Second, countries aren’t in any way compelled to adhere to the insufficient emissions reduction targets they submit under the Paris Agreement. These are only binding insofar as they are made binding by domestic law — and the U.S. has never passed any legislation holding it to its Paris targets. Up until December, the U.S.’s NDC was to reduce greenhouse gas emissions 50 to 52 percent below 2005 levels by 2030 — a goal that many analyses claimed was “within reach” due to investments enabled by Biden’s two signature climate bills, the bipartisan infrastructure law of 2021 and the Inflation Reduction Act of 2022. But as of 2022, U.S. policies would only deliver up to a 42 percent cut in greenhouse gas emissions; the gap would have to be filled with additional actions from states, cities, and private companies.
Meanwhile, the Biden administration also increased oil and gas extraction to record levels, despite repeated warnings from the International Energy Agency — an independent intergovernmental organization — that no new fossil fuel infrastructure is compatible with a pathway to limit global warming to 1.5 degrees C.
Sheila Olmstead, a professor of public policy at Cornell University, said the U.S. exiting the Paris Agreement was “potentially mostly symbolic.” What will ultimately matter, she said, is what the Trump administration does domestically: for example, with vehicle emissions standards, greenhouse gas limits for power plants, and clean energy subsidies under the Inflation Reduction Act, which made $137 billion available for renewable energy infrastructure and climate resilience.
It remains to be seen what Trump will be able to achieve in terms of rolling back those policies, Olmstead said, though he has already signed a spate of executive orders to roll back vehicle emissions standards, pause climate spending under the Inflation Reduction Act, and expand oil and gas drilling on federal lands. State and local resistance could at least partially frustrate the president’s plans to do so — for instance, the U.S. Climate Alliance, a coalition of 24 governors whose states represent more than half of the country’s economy, have pledged to honor the U.S.’s most recent NDC submitted during the waning days of the Biden administration.
Still, a December analysis by the Rhodium Group, an independent research firm, found a deregulatory agenda — the type Trump has begun to enact — could lead to a 24 to 36 percent increase in climate pollution in 2035, compared to current policies.
Sean Gallup / Getty Images
The U.S. exit “threatens to reverse hard-won gains in reducing emissions and puts our vulnerable countries at greater risk,” said Evans Njewa in a statement. Njewa is the chair of the group of least-developed countries at U.N. climate negotiations — a 45-nation bloc including Bangladesh, Ethiopia, and Niger that advocates for ambitious policies at annual climate talks.
For the most part, experts are not concerned that the Trump administration will catalyze a mass exodus from the Paris Agreement. Kaveh Guilanpour, vice president for international strategies at the nonprofit Center for Climate and Energy Solutions, said the U.S.’s exit from the Paris Agreement will be “less consequential” than it was during Trump’s first term, because other countries have had more time to prepare.
“I don’t think it’s in the interests of the United States to leave the Paris Agreement,” he said — but the world “won’t be taken by surprise this time — it knows what’s coming.”
There is no precedent, however, for a climate conference at which the U.S. is a mere observer. The last time Trump pulled out of the Paris Agreement in 2017, U.N. rules made it slow going — no signatory could leave the agreement until “after three years from the date on which this Agreement has entered into force.” By the time the U.S. was officially out, in 2020, the COVID-19 pandemic had postponed talks until the following year — after Biden’s inauguration.
This time around, there’s no three-year buffer period, and it will only take one year for the U.S. to leave the Paris Agreement. Trump may choose not to honor even that abbreviated timeline — his executive order says the country “will consider its withdrawal from the Agreement and any attendant obligations to be effective immediately upon this provision of notification” — but he will technically still be allowed to send a delegation to participate in this year’s round of negotiations, scheduled to take place in November in Brazil. Come COP31, the name for the annual climate conference in 2026, the U.S. will officially be demoted to observer status — still able to attend, but with no decision-making power and no obligation to submit new climate commitments and to report on its progress toward them.
Without the U.S. in the Paris Agreement, it’s possible that other countries will take their climate commitments less seriously — particularly those that are currently led by far-right climate deniers. According to Olmstead, however, that wasn’t really the case last time the U.S. said it was dropping out. “There was a galvanizing nature to it,” she said, prompting Europe and China to reaffirm their commitments to emissions reductions.
Meanwhile, some experts say the structure of the Paris Agreement is at the root of the broader failure to stem rising global emissions. The compact’s bottom-up, voluntary nature is often cited as one of its great strengths and the reason why it garnered buy-in from nearly every country on Earth. But that flexibility clearly becomes a problem when signatories — especially major polluters like the U.S. — choose not to do their fair share.
Olmstead said there are essentially two worldviews when it comes to addressing the climate crisis: the “mother of all collective action problems,” as she described it. The one demanded by the Paris Agreement values fairness and collaboration toward common goals. The one being enacted by the Trump administration, by contrast, is more isolationist, with “every country acting only in its own interest,” and expresses skepticism about the capacity of any international institution to be better than the sum of its parts.
“It’s unfortunate that that worldview is now being applied to climate change,” Olmstead said, “because it doesn’t seem like it’s compatible with addressing it.”
This story was originally published by Grist with the headline Trump leaving the Paris Agreement is ‘mostly symbolic.’ What does it actually mean? on Jan 23, 2025.
The biggest impact on global emissions will be from the new president’s deregulatory agenda. International, Politics Grist
