While touring fire-ravaged California, Donald Trump downplayed the role a warming planet could have in the devastation, suggesting temperatures will "start getting cooler" and that the recent conflagrations was a lack of proper forest management.

"I don't think science knows actually," he said when told that science didn't agree with his conclusions

Meanwhile, on the other side of the country, Joe Biden went on the attack, accusing Trump of ignoring a "central crisis" facing the nation.

"If you give a climate arsonist four more years in the White House, why would anyone be surprised if we have more of America ablaze?" he asked. "If you give a climate denier four more years in the White House, why would anyone be surprised when more of America is underwater?"