Does It Matter If the U.S. Pulls Out of the Paris Accord?

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The Eiffel Tower is illuminated in green with the words "Paris agreement is done," to celebrate the Paris U.N. COP21 climate change agreement, on November 4. Jacky Naegelen/REUTERS

Withdrawing the United States from the global Paris climate agreement, as the White House reportedly plans to do, would create an international uproar. But given that President Donald Trump had no plans to meet the nation's commitments under the agreement, wouldn't pulling out of the agreement be merely a formality? Yes and no, say both critics and advocates of the move.

Related: Trump reportedly decides to pull the U.S. out of landmark accord

The president has already signaled, via a March executive order, that he will scrap the Clean Power Plan, a regulation enacted under his Democratic predecessor to curb carbon emissions from electric power plants. The Clean Power Plan, which was already on hold pending the results of a court challenge from Republican governors, was central to President Barack Obama's plan for meeting the emissions reductions the United States pledged as part of the Paris agreement, which updated the United Nations Framework Convention on Climate Change.

"That's already happening, and there's no way around that," says Brian Deese, a former senior Obama adviser who helped negotiate the 2015 Paris agreement. Along with the Trump administration's rejection of other Obama-era environmental regulations and clean power investments, that will weaken the U.S.'s economic and diplomatic positions on the world stage, Deese predicts. "So the situations is not good, but the question around Paris is, would it be worse for the United States" to pull out entirely?

Deese says yes. While the United States was integral to kick-starting the Paris agreement, which more than 190 nations have now signed on to, nobody expects it to collapse if the Americans withdraw. "I think countries are increasingly seeing it in their political and economic interests to lead on these issues," explains Deese. And he reasons that, even if the Trump administration does not plan to meet the Obama emissions reduction targets, it's still important for the United States to be part of the global climate change dialogue. "Donald Trump doesn't have the ability to stop that momentum and stop Paris, but what he does have the ability to do is handicap the United States."

Moreover, the Paris agreement doesn't officially go into force until 2020, which is when countries are expected to begin reducing emissions, per the voluntary commitments they made when they signed on. Depending on how Trump's re-election effort goes, there could be a new denizen of 1600 Pennsylvania Avenue in 2021, and it could be someone who believes in meeting the United States' Paris obligations. But getting back into the agreement after withdrawing would involve a time-consuming, bureaucratic process.

Opponents of the agreement, however, warn that remaining a party to it even as Trump rejects the carbon emissions commitments would create its own diplomatic headaches, and could even open up the United States government to legal action—a point that's hotly disputed. Christopher Horner, a senior fellow at the Competitive Enterprise Institute, argues that staying in the agreement would ratchet up the pressure on the United States to abide by its commitments. "Under the Paris Agreement, a nation honors its 'non-binding' emission-reduction and climate finance commitments by turning those promises into enforceable obligations—domestic laws and regulations," he wrote in a report published earlier this month. "Thus, the only way to unplug from the pressure machine is to withdraw from the Agreement."

Republican senators have also complained that U.S. participation in the accord sets a bad precedent for the separation of powers within the government. The Obama administration argued at the time that it because it is not a formal treaty, it is not necessary to get Senate ratification. And that would have been a big hurdle, given how opposed many in the GOP-controlled chamber are to climate regulations. One of those senators, Utah Republican Mike Lee, cheered the expected White House decision on Paris Wednesday. "This agreement was negotiated intentionally by the Obama administration to circumvent the Senate's power to advise and consent on international treaties," Lee said in a statement. "They understood it was too unpopular and damaging to U.S interests to ratify."

Horner and fellow lawyer Lucas Bergkamp have also warned that climate activists could sue the government, citing the Trump administration's failure to meet America's emissions reduction commitments as part of the Paris agreement. Those involved in negotiating the agreement say it's nonsense to suggest the Paris commitments were meant to be binding. "This was an issue that was explicitly debated at Paris in the negotiations," says Deese. "Everybody involved in the negotiations…understands that the agreement does not bind the ambition of countries' domestic targets."

Even if the commitments are nonbinding, however, Horner and Bergkamp say there remain legal vulnerabilities—by acknowledging the human risks of climate change and the need for government to act, "governments have embraced a 'duty of care,'" Horner writes, which activists can cite to challenge political inaction. However, the Paris agreement is hardly the only time the United States government has formally laid out the risks climate change poses to Americans. In recent years, both the Pentagon and the U.S. intelligence community have, for example, issued public assessments of the national security risks posed by climate change.

And as Democrat-led states like California and New York have already signaled, pulling out of the Paris agreement will by no means tamp down the pressure from domestic critics. In fact, climate change activists are already preparing to wage a lengthy battle—both legal and political—with the Trump administration. In a pre-emptive statement released Sunday, days before news of Trump's apparent Paris decision leaked, billionaire environmentalist Tom Steyer warned, "If Donald Trump pulls the United States out of the Paris Agreement he will be committing a traitorous act of war against the American people." And Steyer, who funds the environmental advocacy group NextGen Climate, issued a call to others to fill the void: "With Trump hellbent on giving corporate polluters free rein to poison our air and water, states and cities must lead the way."