Donald Trump will withdraw the United States from the Paris climate accord, putting the world superpower at odds with almost every other country on the planet.
The US President made the announcement at the White House on Friday morning (NZ time), saying his predecessor Barack Obama "negotiated poorly" and only signed the 2015 agreement "out of desperation".
Withdrawing from the landmark climate accord, signed by 195 countries in November 2015, will take four years - potentially making it a 2020 presidential election issue.
"The Paris Accord is a BAD deal for Americans, and the President's action today is keeping his campaign promise to put American workers first," a memo sent to supporters read.
Mr Trump had promised an announcement at 7am (NZ time), but was late, not emerging until 7:32am.
He started by addressing the attack in Manila, and talking about the domestic economy - claiming to have produced "hundreds of thousands of jobs" during his recent Middle East trip. Then he made the big announcement.
"We're following through on our commitments, and I don't want anything to get in our way. I am fighting every day for the great people of this country. Therefore, in order to fulfil my solemn duty to protect American and its citizens, the United States will withdraw from the Paris climate accord."
A 'major economic wound'
Mr Trump claimed the "non-binding" accord would cost the US as many as 2.7 million jobs by 2025, and said it was causing "vastly diminished economic production" and "shuttered factories", and preventing the development of "clean" coal technologies.
"I cannot in good conscience support a deal that punishes the United States," said Mr Trump, calling his own country a leader in environmental protection.
He pointed the finger at China and India, two of the world's fastest-growing economies, saying it wasn't fair they had more lenient restrictions.
"China will be allowed to build hundreds of additional coal plants. They can, but we can't... India can double their coal production, we're supposed to get rid of ours... This agreement is less about the climate and more about other countries getting an advantage over the United States."
He called the United States' fossil fuel reserves a "phenomenal wealth" that was being held under "lock and key".
"Even if the Paris Agreement was implemented in full.. it is estimated it would only prevent two-tenths [degC] reduction in global temperature by the year 2100 - a tiny, tiny amount."
The US remains open to another climate deal, Mr Trump said, but it would have to be one that didn't hurt the US economy and "equally shared" the "burdens" with other countries.
"Until we do that, we're out of the agreement."
Ahead of Mr Trump's announcement, Vice President Mike Pence told the crowd gathered at the White House's Rose Garden the President has been "fighting every day to make America great again", and pulling out of the Paris Agreement is part of that.
"Thanks to President Donald Trump, America is back."
The head of the US Environmental Protection Agency, Scott Pruitt, called Mr Trump's decision "an historic restoration of American economic independence". Mr Pruitt is a climate change sceptic.
Pleas to stay
His daughter Ivanka had previously urged him not to pull the US out of the agreement, which aims to keep global warming beneath 2degC by the end of the century. Scientists say not doing so would result in catastrophic sea level rises and more frequent extreme weather events.
The only other countries not party to the Paris accords are Nicaragua and Syria. The agreement even has support from fossil fuel giants Royal Dutch Shell, ExxonMobil and BP.
Nicaragua didn't sign because it felt the agreement wasn't strong enough. Syria has been in civil war for years, and international sanctions on its leadership made it impractical to attend.
New Zealand's pledge under the Paris Agreement is to reduce emissions by 30 percent below 2005 levels by 2030. It's expected to cost $1.4 billion a year in carbon credits.
Mr Trump has previously called climate change a Chinese "hoax". NZ Prime Minister Bill English has recently come around to the view it's real, but as recently as 2013 was only willing to say it "may well be".
Vatican calls it a 'slap in the face'
Earlier the Vatican, which under Pope Francis' insistence has strongly backed the Paris climate change deal, said a US withdrawal would be a slap in the face and a "disaster for everyone".
At their meeting last month, the Pope gave Mr Trump a signed copy of his 2015 encyclical letter that called for protecting the environment from the effects of climate change and backed scientific evidence that it is caused by human activity.
Vatican Secretary of State Cardinal Pietro Parolin urged Mr Trump in a separate meeting not to quit the Paris accord.
"If he really does [pull out], it would be a huge slap in the face for us," said Bishop Marcelo Sanchez Sorondo, head of the Pontifical Academy of Sciences, which has hosted numerous international conferences on climate change.
"It will be a disaster for everyone," he told the Rome newspaper La Repubblica.
In a statement, Mr Obama said his administration's signing of the Paris Agreement was the result of "steady, principled American leadership on the world stage".
"It was bold American ambition that encouraged dozens of other nations to set their sights higher as well."
Mr Obama said Mr Trump's economic arguments don't stand up, because "the private sector already chose a low-carbon future".
"The Paris Agreement opened the floodgates for businesses, scientists and engineers to unleash high-tech, low-carbon investment and innovation on an unprecedented scale."
Mr Obama said he has confidence "states, cities and businesses" will continue to go down a low-carbon path, with or without the White House. On Thursday (NZ time), New York Mayor Bill de Blasio said his city would uphold the agreement, despite Mr Trump's "dagger aimed straight at the heart of New York City".
Opposition at home
US supporters of the accord condemned Trump's move as an abdication of American leadership and an international disgrace.
"At this moment, when climate change is already causing devastating harm around the world, we do not have the moral right to turn our backs on efforts to preserve this planet for future generations," said US Senator Bernie Sanders, who sought the Democratic presidential nomination last year.
"Ignoring reality and leaving the Paris agreement could go down as one of the worst foreign policy blunders in our nation's history, isolating the US further after Trump's shockingly bad European trip," Democratic Senator Sheldon Whitehouse added.
Tech entrepreneur Elon Musk announced he was quitting the President's advisory council as a result of the withdrawal.
"Climate change is real. Leaving Paris not good for America or the world," he tweeted.
Reuters / Newshub.