group of 375 "concerned" scientists -- including famed physicist Stephen Hawking -- released an open letter Tuesday sharply criticizing Donald Trump, citing the threat of climate change and blasting his push for the US to leave the Paris Accord.

"It is of great concern that the Republican nominee for President has advocated U.S. withdrawal from the Paris Accord. A 'Parexit' would send a clear signal to the rest of the world: 'The United States does not care about the global problems of human-caused climate change. You are on your own,'" the group wrote on the website