The United States on Monday formally notified the United Nations that it was withdrawing from the Paris climate accord, making the world's largest economy the sole outlier from the agreement.
The US President,Mr. Donald Trump, went ahead with the pullout despite mounting evidence of the reality and impact of climate change, with September the fourth month in the row with near- or record-breaking temperatures.
The US presented its withdrawal letter to the UN on the first possible date under the accord negotiated by Mr. Trump's predecessor, Mr. Barack Obama.
It will be officially out of the Paris accord on November 4, 2020, one day after the US election in which Mr. Trump is seeking a second term.
Announcing the move, the Secretary of State, Mr. Mike Pompeo, reiterated Mr. Trump's remarks in 2017 that the agreement imposed an 'unfair economic burden' on the US.
'The US approach incorporates the reality of the global energy mix and uses all energy sources and technologies cleanly and efficiently, including fossils fuels, nuclear energy and renewable energy,' Mr. Pompeo said in a statement.
The US is still planning to attend this month's COP climate negotiations in Spain, according to a State Department official.
Pledging to pursue a 'realistic and pragmatic model,' Mr. Pompeo pointed to a 13 percent US reduction of greenhouse gas emissions blamed for climate change from 2005 to 2017 even as the economy grew.
But Mr. Trump, who took office in 2017, has also pledged to turn back environmental regulations, seeking to block California from setting tighter standards on car emissions and moving to let states set their own standards on existing coal-fired power plants.
A number of states, notably California and New York, have taken the lead in fighting climate change in the face of hostility by Mr. Trump.