Donald Trump made it clear on the campaign trail that he would not honor the commitment made by the U.S. in the Paris Agreement.

The pact, adopted in December 2015 at the Paris climate conference known as COP21, is the world’s first legally binding global deal to combat climate change.

Now that Trump occupies the White House, he hasn’t been so quick to pull the trigger on Paris.

Will he stay or will he go? And whatever he decides, what will be the effect on other countries?

Trump is known for being mercurial, so it’s pure speculation on anyone’s part — regardless of his or her closeness, or lack thereof, to the president — what he will decide regarding the Paris Agreement.

“It’s anyone’s guess,” Robert Stavins, director of the Harvard Environmental Economics Program, said during a phone interview. “Whatever he decides this afternoon, he may have a different view tomorrow morning. He reaches decisions on gut instinct.”

There are rival factions in the White House arguing for or against remaining in the pact, which was signed by over 195 nations. Reports indicate that first daughter and presidential adviser Ivanka Trump, her husband and presidential adviser Jared Kushner and Secretary of State Rex Tillerson are pushing for the U.S. to remain, while presidential adviser Stephen Bannon and Environmental Protection Agency Administrator Scott Pruitt are pushing for an exit.

The White House had been saying that Trump would make a decision on the Paris Agreement before the G7 Summit at the end of May in Italy, but backtracked and said a decision would not be made until after the summit (the other G7 countries all reaffirmed their support for the deal, while Trump abstained).

Many environmental experts say that if Trump decides to pull out of Paris, while it would damage the U.S. on the international front, it is highly likely that the other parties to the agreement would move forward with their commitments.

A Primer on Paris

The formal international effort that led to the landmark Paris Agreement started about 25 years ago with the United Nations Framework Convention on Climate Change (UNFCCC), which was ratified as a treaty by the U.S. Senate in 1992 and entered into force in 1994. Article 2 of the UNFCCC commits the parties to achieving “stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.”

The Kyoto Protocol, adopted in 1997 and entered into force in 2005, took the UNFCCC further by setting internationally binding emission reduction targets. Kyoto, setting up a cap-and-trade system for emissions, placed a heavier burden on developed nations for greenhouse gas responsibility and gave developing nations, including China and India, more leeway for emissions. This did not sit well with the U.S., which decided not to be a party to Kyoto.

The Paris accord, also built upon the UNFCCC, was adopted in December 2015 and entered into force October 2016. Paris sets a goal of keeping a global temperature rise this century below 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels, as well as limiting the temperature increase to 1.5 degrees Celsius.

There are 197 parties to Paris, with 146 having ratified it thus far. While Paris is legally binding, all commitments are voluntary and the deal gives each country the flexibility to decide how it will honor the agreement, specifically through “nationally determined contributions” (NDCs).

There will be a general check-in among the parties in 2018 to take stock and prepare for the NDCs. Collective progress will be tracked every five years and individual actions by parties reassessed.

Breaking from Obama

Trump has made no secret that he wishes to undo Obama’s legacy climate policies. Obama has been laying low post-presidency, but he did come out publicly to push for the U.S. to maintain its Paris commitment.

Trump has proposed significant cuts to the Environmental Protection Agency and in March, he signed an executive order that instructed the EPA to formally withdraw from Obama’s Clean Power Plan, which limits greenhouse gas emissions from the coal industry and encourages renewable energy.

America’s NDC, pledged by Obama, aims to reduce net greenhouse gas emissions by 26 percent to 28 percent below 2005 levels in 2025. Obama’s Clean Power Plan was key to meeting that NDC. Trump dismantling Obama’s plan does not necessarily mean, however, that he will walk away from the Paris Agreement.

Legal Issues

Because Paris is legally binding, there is a formal process for withdrawal.

“While a party can at any time announce its future intention to withdraw from the Paris Agreement, it cannot actually begin the withdrawal process until it has been a party for three years,” wrote Susan Biniaz in an email. Biniaz is an environmental lawyer with a long history at the State Department who played a major role for the U.S. in the Paris talks.

“For the United States, that would mean that it could give formal notice of withdrawal no earlier than November 2019. That notice of withdrawal takes effect one year later,” she wrote.

Supporters of the “remain” camp say a formal withdrawal serves no purpose because the agreement relies on voluntary, nonbinding commitments, so there are no penalties if nations miss their targets. Staying involves largely attending meetings and producing reports. Leaving would produce a diplomatic backlash (and possibly trade barriers imposed by other nations against the U.S.), while putting Washington in the dubious company of the only two other nonparticipating countries: Syria and Nicaragua. Environmentalists also point out that Paris leaves open the possibility of lowering a nation’s commitments down the line.

While environmentalists would be upset if Trump withdraws the U.S. from Paris, “There would not appear to be any basis for a legal challenge, either internationally or domestically,” according to Biniaz.

But some administration officials disagree on that legal interpretation and worry that remaining in the agreement could leave the White House vulnerable to potential lawsuits, especially because the president’s energy policies emphasize fossil fuels over renewables. Ditching the accord could also represent a much-needed political win, even if it is a largely symbolic one, for a president who’s been besieged by one crisis after another.

The Trump Effect

If Trump does exit from Paris, it would likely satisfy his base but have an overall negative effect on the U.S. in the international community in terms of image, relationships and negotiating power.

“For the world’s largest economy to walk out would be a massive diplomatic blunder. It would be difficult to recover from,” Paul Bledsoe told The Diplomat. Bledsoe was an adviser on climate change in the Clinton administration and is now a senior fellow at the Progressive Policy Institute and a lecturer at the American University Center for Environmental Policy.

Trump’s decision on Paris will affect the ability of the U.S. to negotiate trade deals and the international coordination of diplomatic and national security policies, Bledsoe believes.

“Before the Trump presidency, climate change was one of the few bright spots in international relations,” wrote Kelly Sims Gallagher, director of the Center for International Environment and Resource Policy at Tufts University, in an email. “It smoothed relations with allies in Europe and with China in particular. It is always helpful to be constructive when one can so that when you need help, you have the ability to ask for it.”

Abandoning Paris would hurt the U.S. by making it “a pariah,” Stavins of the Harvard Environmental Economics Program said.

One of the main diplomatic arguments against withdrawal is that the U.S. would give up an important seat at the table for a first-order international issue.

“From a global leadership point of view, that is something that should concern the administration, and they should not want to cede that kind of leadership,” Carol Werner, executive director of the Environmental and Energy Study Institute, told The Diplomat.

If the U.S. withdraws from Paris, there will be a leadership vacuum, and the mantle will likely fall to China, now the world’s biggest polluter, followed by the U.S. and India. It would be China’s chance to step up and take the moral high ground vis-à-vis the U.S. on a major international issue.

“China seems quite pleased going from co-leadership with the U.S. to sole leadership,” said Stavins. “It’s not changing its NDC or internal policies and actions.”

While the loss of the U.S. would be a huge moral blow to the agreement, China’s continued participation in it is vital because the country now consumes as much coal as the rest of the world combined.

Beijing also has a vested self-interest in curbing climate change: It is grappling with record-level pollution and smog perpetuated by both the burning of coal and changing weather patterns. In addition, the country is aggressively pushing to expand its share of the increasingly lucrative clean energy market, which is estimated to be worth trillions of dollars in the coming decades.

Experts predict both developed and developing nations will likely stick with Paris no matter what the U.S. does. “This was difficult enough to get to this point,” said Stavins. “The U.S. will be condemned [if Trumps withdraws], but they’ll continue with the work,” he said of the other parties to Paris.

Clean Energy Boom

Whether the U.S. remains a party to Paris, it is clear that the Trump administration has no interest in addressing climate change, which he famously called a hoax perpetuated by China.

“I don’t think anyone is under any illusions that the Trump administration will be pursuing implementing policies to honor the U.S. pledge,” wrote Gallagher by email.

But the U.S. will not stop advancing on clean energy. No matter what Trump does, experts say that local governments, businesses, consumers, technological innovations and market forces will continue to drive the shift toward renewables.

For instance, California Gov. Jerry Brown has positioned himself in contrast to Trump’s anti-environmental policies by declaring that the state of nearly 40 million people will fight for climate change issues. Brown made good on his stance by signing legislation that will cut California’s greenhouse gas emissions to 40 percent below 1990 levels by 2030.

Likewise, cities such as New York City have been pioneers in green and sustainable living. Major corporations, including fossil-fuel companies, are also advocating for progressive climate policies that they say are more economically viable in the long run. On April 26, several corporations sent a letter to Trump stating their support for remaining in the Paris Agreement. Signatories include the oil and gas majors BP and Shell and the utility company PG&E.

“Climate change presents U.S. companies with both business risks and business opportunities,” the letter states. “U.S. business interests are best served by a stable and practical framework facilitating an effective and balanced global response. We believe the Paris Agreement provides such a framework.”

“I think the horse is out of the barn,” said Werner. “We are already in an energy transition in this country. That is also happening globally.”

The Clean Power Plan would have enforced carbon pollution limits on electricity production starting in 2022 and going into full effect by 2030. Power companies would have had to begin getting ready for the new regulations well before 2022.

“Already we were a long ways toward reaching that first goal without the plan going into effect because the Clean Power Plan was following trends as opposed to leading,” Werner argued.

Environmentalists point out that coal plants simply are no longer as profitable as they once were — and that the mining jobs Trump has promised to bring back are never coming back, largely because of automation in the workforce and market trends. A decade ago, coal was the source of half the nation’s electricity supply; today, it’s down to one-third as cheaper alternatives like natural gas come online. And as the cost of producing wind, solar and other renewables continues to fall, economists say this trend will only accelerate. In fact, solar energy now employs more Americans than coal, gas and oil combined.

The Global Trends in Renewable Energy Investment 2017 report by the U.N, Frankfurt School-UNEP Collaborating Centre and Bloomberg New Energy Finance shows that global investment in renewable energy reached $241.6 billion in 2016, which is 23 percent less than the investment in 2015, largely because of the falling prices for renewable energy technologies. The average dollar capital expenditure per megawatt for solar photovoltaics and wind dropped by more than 10 percent. The proportion of global electricity provided by renewables rose from 10.3 percent in 2015 to 11.3 percent in 2016, preventing an estimated 1.7 gigatonnes of carbon dioxide from being released into the atmosphere.

Investments in renewables are happening in developing nations as well. “While India had a lot of coal in their plans, within the last year, we have seen a really huge turnaround in terms of their commitment with renewables,” said Werner. “Like with China, so much is being driven by public health concerns and severe air pollution.”

Global trends are showing growth in renewables that is beyond Trump’s “America First” agenda.

“I believe the Paris agreement will far outlast the Trump presidency whether the U.S. stays in or not,” Bledsoe said. “The agreement itself is not subject to Donald Trump’s whims. It will continue long after he has left the world stage.”

About the Author

Aileen Torres-Bennett is a freelance writer in Washington, D.C.