Washington, Sep 21 (IANS): Hundreds of top scientists have published an open letter warning against claims by Republican presidential nominee Donald Trump that if elected he would advocate US withdrawal from the 2015 Paris Accord on climate change.

"Human-caused climate change is not a belief, a hoax, or a conspiracy. It is a physical reality," said Tuesday's letter, signed by 375 members of the US National Academy of Sciences, including 30 Nobel laureates and renowned scientists such as Stephen Hawking.

The withdrawal would "send a clear signal to the rest of the world that the US does not care about the global problem of human-caused climate change", Xinhua news agency cited the letter as warning.

The letter also said the consequences of opting out of the Paris agreement would be severe and long-lasting for our planet's climate and for the international credibility of the US.

"The US can and must be a major player in developing innovative solutions to the problem of reducing emissions of greenhouse gases," it wrote.

"Walking away makes it less likely that the US will have a global leadership role, politically, economically, or morally. We cannot afford to cross that tipping point."

Trump has called climate change "a hoax" and said the Paris Accord was "bad for US business".

"We're going to cancel the Paris climate agreement and stop all payments of US tax dollars to UN global warming programmes," he said on May 26 this year.