US President Joe Biden calls climate change an 'existential threat'

US President Joe Biden announced measures to bolster heat-related safety rules for workers

US President Joe Biden on Thursday called the soaring temperatures from climate change an "existential threat."

"I don't think anybody can deny the impact of climate change anymore," Biden said at the White House, where he held a video conference with the mayors of heat-blasted Phoenix, Arizona, and San Antonio, Texas.

Biden said heat is the "number one weather-related killer" in the United States, causing 600 deaths every year.

He also announced measures to bolster heat-related safety rules for workers -- especially farmers, construction workers and others laboring outdoors -- and additional funding for the weather forecasting service.

Phoenix Mayor Kate Gallego told Biden that her desert city "is known for heat... but right now this summer has really been unprecedented."

"It's taking a real toll on our community. We feel like we're very much on the frontlines of climate change," she said.

Addressing San Antonio Mayor Ron Nirenberg on the video link, Biden quipped: "I hope the air conditioning's working."