The Senate budget committee held a hearing on Wednesday morning to scrutinize the role of oil- and gas-linked “dark money” in delaying climate action – and tearing through local and federal budgets.

The hearing was led by Senator Sheldon Whitehouse of Rhode Island, who has held 10 climate crisis-focused hearings since he took the helm of the budget committee this past February.

It follows an inquiry launched by House Democrats in 2021, which focused on big oil’s alleged efforts to mislead the public about the climate crisis.

“I am shining a light on the massive, well-documented economic risks of climate change,” said Whitehouse, who has also given nearly 300 speeches about the climate crisis on the Senate floor. “These are risks that have the potential to cascade across our entire economy and trigger widespread financial hardship and calamity.”

In his opening remarks, Whitehouse described the well-documented misinformation campaign that fossil fuel interests have waged on the American public.

“Beginning as early as the 1950s, industry scientists became aware of climate change, measuring and predicting it decades before it became a public issue,” he said. “But industry management and CEOs spent decades promoting climate misinformation.”

Ranking member Senator Chuck Grassley, a Republican from Iowa, said the hearing was a “missed opportunity to work together on a responsible budget”. He also claimed Democrats obtain “much more secret or dark money than Republicans”.

Committee Democrats invited three witnesses. First to the stand was the Harvard history of science professor Naomi Oreskes. “Climate change is a market failure, and market failures require government action to address,” she testified.

Fossil fuel interests’ efforts to disrupt climate policy had come at great expense to the US, including not only financial costs, but also human suffering and lives lost, said Oreskes, who has written several books on oil industry misinformation.

Christine Arena, former public relations executive at the firm Edelman who now works in social impact film-making, and who was also invited by Senate Democrats, drew comparisons between the fossil fuel industry’s decades-long misinformation campaign and how the tobacco industry tried to cover up the harms of smoking.

“Just like the tobacco executives before them, [fossil fuel executives] characterize peer-reviewed science and investigative journalism that illustrates the extent of their deceptions as biased or inconclusive,” said Arena, who is now the founder of Generous Films.

Richard Painter, professor of corporate law at the University of Minnesota Law School who was chief White House ethics lawyer under George W Bush, was third to testify. A political independent, Painter said Americans should get on board with the push to end climate misinformation no matter where they fall on the political spectrum.

“This is not a partisan issue,” said Painter, who was also invited by Whitehouse. “This is about caring, and doing something about a grave threat to the human race.”

The last two witnesses were invited by Republican senators. First up was Dr Roger Pielke Jr, professor of environmental studies at the University of Colorado, Boulder, who said he believed climate change was real, human-caused and dangerous, but that the Democrats’ concerns were overblown.

Last to testify was Scott Walter, president of the conservative non-profit Capital Research Center who served in the George W Bush administration as special assistant to the president for domestic policy. “To say that a group uses dark money is like saying the group uses telephones. It’s a universal technology,” he said.

He insisted that dark money was not a major problem in American politics. Insofar as it was a problem, he said, the political left took more money than the right.

In an interview after the hearing, Oreskes said she suspected the evidence that Democrats take more dark money than Republicans may be based on “cherry-picked” data. “Cherry-picking is a tactic we know climate deniers and skeptics have used for decades,” she said.

In an email to the Guardian after the initial publication of this article, Walter defended his assertion in the hearing about the Democrats and dark money. He said that “reputable, non-conservative, non-fossil-fuel-funded sources” including CNN, OpenSecrets, and the New York Times have reported on Democrats’ outsized acceptance of dark money in recent years, particularly President Biden’s on the 2020 campaign trail.

While being questioned by Whitehouse, Oreskes said that in the mid-2000s, she and others who wrote about the scientific consensus on the human-caused climate crisis received hate mail and were the targets of official complaints and other attacks.

“That experience of being attacked led me to try to understand what these attacks were, who was funding them, who was behind them, and why they were doing it,” she said.

Later, Grassley asked Walter to talk more about the influence dark money has on Democrats. “I can’t explain exactly why your colleagues aren’t willing to look at the dark money ties of their own witnesses,” said Walter.

Senator Jeff Merkley of Oregon, a Democrat, addressed these allegations, offering a solution for his Republican colleagues who are concerned about dark money’s influence on Democrats. The Disclose Act, introduced by Whitehouse in the Senate this year, would expose the sources of these clandestine funds for Democrats and Republicans alike, he said. “I would invite my colleagues across the aisle to join us in ending dark money on both sides,” said Merkley.

Dharna Noor

This article was amended on 22 June 2023. An earlier version misspelled Scott Walter’s name as “Scott Walker” and misattributed one of his quotes to Roger Pielke. It was further amended on 23 June 2023 to add a post-publication comment from Scott Walter.