"We're getting out, but we will start to negotiate and we will see if we can make a deal that's fair," Trump said. "And if we can't that's fine."
The announcement came on Thursday afternoon following much speculation about exactly how the US president would exit the accord amid pushback from around the world. Still, the action is less than a surprise given his rhetoric on the campaign trail and general anti-climate science position.
The agreement stipulates that countries need to wait three years before withdrawing, at which point they can file a notice of intent to withdraw, which will go into effect exactly one year later. This means that the US would effectively exit in 2020. Other than that, Trump could also withdraw the US from the United Nations Framework Convention on Climate Change (UNFCCC). This requires a one year notice and would automatically axe the US from the Paris accord. It is the path advocated by the Heritage Foundation, a neocon think tank.
Trump's decision would make the United States one of only three UN member states to not to participate in the climate agreement (the other two being Nicaragua and Syria). He has the power to leave the agreement by executive order, rather than Senate approval, which is also how Obama entered the agreement last year.
Former President Barack Obama, who was responsible for bringing the US into the Paris Agreement, issued a statement calling it "the first-ever global agreement to set the world on a low-carbon course and protect the world we leave to our children." He added that "states, cities, and businesses will step up and do even more to lead the way," now that the US is backing out.
Elon Musk tweeted that he is resigning from his role on two presidential advisory councils, which he'd earlier threatened to do if the US withdrew:
On Thursday, with a decision looming, a number of tech industry leaders such as Apple, Facebook and Google came together to run a special advertisement urging Trump not to pull out from the climate agreement. Even Rex Tillerson, Trump's Secretary of State and the former CEO of ExxonMobil, has said that US should remain in the climate treaty.
After China, the US is the second largest contributor to global carbon emissions: China contributes about 20 percent and the US contributes 18 percent. Collaboration between the two countries was considered paramount to successfully achieving the goal of the Paris accord: to keep the average global temperature "well below 2C above pre-industrial levels."
At the time the agreement was signed, average global temperatures were about 1.3C above pre-industrial levels.
"This is not first and foremost about saving the environment for its own sake," Paul Bodnar, who helped negotiate the treaty, told Motherboard staff writer Jason Koebler. "It's about protecting our economic and security interests around the world. If you support food security, global health, poverty eradication, you should be very concerned about how climate change works to counteract those goals."
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The US exit from the Paris treaty is bearing out the prophecy of the accord's critics, who warned that the agreement is toothless since it didn't include any legally binding mechanisms. There are no penalties if signatories leave the agreement, which prompted speculation that a few countries exiting the accord could lead to a collapse of the entire effort.
the United States has shied away from its responsibilities as a world leader. Although the EU and China have vowed to strengthen their own climate agreements in the event of a United States withdrawal, it isn't clear how much this will offset the impact of the US exit.
For now, the future of the Paris treaty—and in some sense, the future of the planet—is out of American hands.
Update: We have updated this story with quotes from Donald Trump's announcement that the United States will withdraw from the Paris climate agreement, and with former President Barack Obama's statement and Elon Musk's tweet following Trump's speech, as well as with a tweet from the Associated Press including a statement from Angela Merkel.