"I spoke with Lee Zeldin and he thinks he's going to be cutting 65 or so percent of the people from environmental," he said, referring to the EPA administrator.

The agency currently employs more than 17,000 people, of the roughly two million total US federal workforce.

Trump has made slashing the size of the federal government a key priority in his first days in office, tasking Elon Musk, the world's richest person, with aiding that effort as well as cutting government spending.

The Republican ran on a platform that promised to curb environmental protection regulations, specifically those related to climate change, in order to increase economic growth.

He has called climate change a "scam," and pulled Washington out of the landmark Paris Agreement for a second time on his first day back in office.

Since then, he has declared a "national energy emergency" to expand domestic oil drilling, and signed executive orders to slow the transition to electric vehicles and halt offshore wind farm projects.

Zeldin, a former US congressman from New York, has committed to delivering Trump's campaign promises, although he acknowledged last month that man-made climate change was "real."

He has said he would prioritize the EPA's role in ensuring clean water and air, but appears set to roll back a host of other environmental regulations.

"The EPA is going to aggressively pursue an agenda powering the Great American Comeback... that's our purpose," he said earlier this month.

The new EPA administrator has appeared to embrace Musk's government spending cut efforts, announcing on Tuesday that the agency had slashed $60 million in grants that were funding "wasteful DEI and environmental justice programs," referring to diversity, equity and inclusion.

Most scientists agree that climate change currently underway differs from natural cycles of the past.

The Intergovernmental Panel on Climate Change says it is indisputably attributable to human activity, and in particular to the burning of fossil fuels, especially since the end of the 19th century.