Photo taken on Dec. 23, 2021 shows ExxonMobil Baytown Olefins Plant in Baytown, Texas, the United States.(Photo: Xinhua)

US climate scientists accused four of the world's largest oil companies Tuesday of lying about the harms linked to their industry and trying to delay the switch to cleaner fuel.

US multinationals ExxonMobil and Chevron, as well as Britain's BP and Shell, are being investigated by the US Congress for their role in spreading misinformation about climate change. 

Michael Mann, an academic, told the House oversight committee the companies had known for more than four decades that their activities caused pollution, but had engaged in a "campaign of denial and delay." 

"We are now paying the price for these delays in the form of extreme weather events," said the Pennsylvania State University atmospheric science professor.

He pointed to the so-called heat dome under which millions of Americans and Canadians sweltered in June 2021, and the wildfires that regularly devastate swathes of California. 

He also dismissed the oil giants' strategy of promising to reduce the carbon intensity of their fossil fuels.

"That's sort of like your doctor telling you that you need to cut fat from your diet," he said.

"And so you switch to 40 percent reduced fat potato chips, but you eat twice as many of them. That doesn't help."

Executives of the oil companies were invited to appear but did not show up. They did testify in October, telling lawmakers they had accelerated investment in alternative energy in recent years. 

Tracey Lewis, the policy counsel for advocacy group Public Citizen, rejected the pledges as "climate disinformation and greenwashing."

She said she was particularly concerned over misinformation targeting people of color and the poor, who are disproportionately harmed by the burning of fossil fuels.

Republicans defended the companies, pivoting instead to attack President Joe Biden's climate initiatives, linking them to a recent rise in energy prices. 

"Good luck getting on an airplane powered by batteries," said South Carolina congressman Ralph Norman. 

AFP