Video report by ITV News Washington Correspondent Robert Moore
Donald Trump has confirmed the US will abandon the landmark 'Paris Accord' global climate change deal in the face of domestic and international condemnation.
The US president, who had pledged to quit the deal during last year's election campaign, said he will be seeking a better deal for US workers.
"I was elected to represent the citizens of Pittsburgh, not Paris," he said.
Mr Trump has previously described climate change as a hoax by the Chinese to damage US manufacturing.
His predecessor Barack Obama, who signed up to the deal alongside 194 other countries in 2015, condemned the decision.
Mr Obama bemoaned the "absence of American leadership" that had seen the US join "a small handful of nations that reject the future".
Former secretary of state John Kerry said the "big mistake" was a "self-destructive step that puts our nation last".
The US joins only Syria and Nicaragua in refusing to commit to reduce carbon emissions.
Mr Trump confirmed in a televised statement his move to scrap the deal that had still to be ratified by the US Senate.
"In order to fulfil my solemn duty to protect America and its citizens, the United States will withdraw from the Paris climate accord," he said to applause from the audience in the White House Rose Garden.
The president said the US would begin renegotiations to "re-enter the Paris Accord or an entirely new transaction" on "fairer terms" to the US, its businesses, its workers and its taxpayers.
"We're getting out," he said. "But we will start to negotiate and we will try to see if we can make a deal that's fair.
"And if we can, that's great. And if we can't, that's fine."
In phone calls with the leaders of the UK, France, Germany and Canada, President Trump said that despite pulling the US out of the global agreement, America remained committed "to robust efforts to protect the environment".
Mr Trump continued that the US had a strong record in reducing emissions and leading the development of clean energy technology, and reiterated that the US under the Trump Administration, would be the cleanest and most environmentally friendly country on Earth.
ITV News Washington Correspondent Robert Moore said the withdrawal was the "most controversial decision for decades" by a US president.
Mr Trump said the Paris Accord was the "latest example of Washington entering into an agreement that disadvantages the United States to the exclusive benefit to other countries".
He said it left American workers and taxpayers to "absorb the cost in terms of lost jobs, lower wages, shut factories and vastly diminished economic production".
ITV News Science Correspondent Alok Jha spotted flaws in Mr Trump's reasoning for quitting, while adding the lengthy withdrawal process could count against the president.
Mr Obama's rejected Mr Trump's justification for reneging on a key part of his predecessor's presidential legacy, saying the US would now not be among the nations that "reap the benefits in jobs and industries created" by the Paris Accord.
But Mr Obama added: "I'm confident that our states, cities, and businesses will step up and do even more to lead the way, and help protect for future generations the one planet we've got."
Mr Trump's claim that he was representing the interests of the people of "Pittsburgh not Paris" was undermined by the Pennsylvania city's mayor.
World leaders spent years in difficult negotiations to produce an agreement that includes a pledge for countries to take action to limit temperature rises to "well below" 2C above pre-industrial levels.
China said prior to Mr Trump's announcement it will work with the EU to uphold the international agreement even if the US withdrew.
China's Premier Li Keqiang said fighting climate change is an "international responsibility", adding: "It's not invented by China... and we realise that this is a global consensus agreement."
Russia also said it supports the climate agreement and said it would be less effective without the major participants.