President Donald Trump has announced his decision to withdraw the US from the 2015 Paris climate change agreement.
Trump said he would negotiate a new "fair" deal that would benefit US businesses and workers.
During his presidential election campaign last year, Trump had warned he would take steps to help American oil and coal industries.
The move was met with global condemnation.
Trump said the Paris agreement was aimed at leaving the US economy disadvantaged and impoverished.
He said: "I was elected to represent the citizens of Pittsburgh, not Paris. I promised I would exit or re-negotiate any deal which fails to serve America's interests."
Trump didn't provide a timeline for the US withdrawal but White House officials had earlier said it could take four years.
Analysts believe the US withdrawal will make it tougher for the world to reach the carbon emission goals it set for itself in the Paris agreement.
The US contributes around 15% of global carbon emissions.
It's also a major contributor of finance and technology for developing countries trying to fight global warming, which may come to an end.
Former US President Barack Obama lamented Trump's decision saying the Paris agreement was meant to "protect the world we leave to our children."
He accused Trump of "rejecting the future."
"The nations that remain in the Paris Agreement will be the nations that reap the benefits in jobs and industries created," he added.
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