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. President 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 United States presented its withdrawal letter to the United Nations on the first possible date under the accord negotiated by Trump's predecessor Barack Obama.
It will be officially out of the Paris accord on Nov 4, 2020, one day after the US election in which Trump is seeking a second term.
Announcing the move, Secretary of State Mike Pompeo reiterated Trump's remarks in 2017 that the agreement imposed an unfair economic burden on the United States.
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, Pompeo said in a statement.
The United States 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, Pompeo pointed to a 13 per cent US reduction of greenhouse gas emissions blamed for climate change from 2005 to 2017 even as the economy grew.
But 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 Trump.
Robert Menendez, the top Democrat on the Senate Foreign Relations Committee, said that the Trump administration has once again thumbed its nose at our allies, turned a blind eye to the facts and further politicized the world's greatest environmental challenge.
Former vice president turned climate champion Al Gore deplored Trump's decision - but said that a new president could re-enter the Paris accord within 30 days.
No one person or party can stop our momentum to solve the climate crisis, but those who try will be remembered for their complacency, complicity and mendacity in attempting to sacrifice the planet for their greed, Gore said.