Kathleen Hartnett White stammered, sighed and sat silent for seconds on end on Wednesday throughout her Senate hearing to be confirmed as the new head of the White House’s Council on Environmental Quality.

It was an unusually tongue-tied performance for someone who has been a bombastic critic of climate and environmental science.

The former Texas environmental state regulator turned climate pundit has argued that “carbon dioxide has none of the attributes of a pollutant,” dismissed it as a “harmless trace gas” and “plant food,” and compared Pope Francis’ public advocacy for action to curb global warming to the Catholic Church’s arrest of Galileo for heresy in 1633. She equated the belief in the overwhelming evidence that man-made greenhouse gas emissions are warming the planet to “paganism,” and accused United Nations leaders calling for climate action of advocating totalitarian communism. Hartnett White deflected those quotes as taken out of context when raised repeatedly by Democratic senators on Wednesday.

In a nearly three-hour long hearing on Wednesday, senators probed Hartnett White and Andrew Wheeler, the former coal lobbyist nominated to be the deputy administrator at the Environmental Protection Agency. Both nominees reject the science behind global warming, and have close ties to industries that stand to lose the most money from regulations to curb climate change. Wheeler, a former legislative aide to Sen. Jim Inhofe (R-Okla.), couched many of his objections to climate science in polished, ambiguous legalese, which has earned him a reputation among environmentalists as a competent operator capable of dismantling Obama-era fossil fuel regulations.

But Hartnett White ― who Sen. Ed Markey (D-Mass.) described as “a fringe voice that rejects science, economics, and reality” ― withered under intense questioning from Democratic senators. She struggled on five separate occasions to defend her rejection of mainstream climate science.

1. ‘I am uncertain ― no, I’m not.’

Senate EPW A screenshot from the live-streamed hearing, where Kathleen Hartnett White testified.

She fumbled when Sen. Ben Cardin (D-Md.) asked if she believes climate change is real.

“I am uncertain,” she said, then corrected herself: “No, I’m not. I jumped ahead. Climate change is of course real.” Then she said she’s uncertain about the extent to which humans are to blame:

CARDIN: Would you rely on scientists to give you that answer or not? HARTNETT WHITE: No, I had that question for a very long time. A very long time. CARDIN: You have a distinguished background in academics, in humanities and religion. Which is fine. It’s a wonderful field. You’re not a scientist, are you? HARTNETT WHITE: No, I’m not a scientist, but in my personal capacity I have many questions that remain unanswered by current climate policy. I think we indeed need to have more precise explanation of the human role and the natural role.

2. ‘I have a very superficial understanding.’

Oceans absorb about one-quarter of the carbon dioxide released into the atmosphere each year, according to data from the National Oceanic and Atmospheric Administration. The increased CO2 causes a series of chemical reactions that result in higher concentrations of hydrogen ions and more acidic water. It’s a widely-understood process, ably explained on NASA’s website for children. Yet when Sen. Sheldon Whitehouse (D-R.I.) asked whether she was aware of “anything that is happening in the oceans that relates to fossil fuel emissions,” she said: “There are probably a number of them.”

WHITEHOUSE: Name a few. HARTNETT WHITE: I have a very superficial understanding as far as that. But acidification issues is one. I have not read widely or deeply. I have read some, different perspectives, some of which suggest that it is a very, very fragile set of changes in acidification. I have others that say for long eons of geological history, certain places of certain oceans may have changes of acidification levels and not others. Changes up and down are not inherently a problem but I cannot speak with authority on that. But I’m aware it’s among the multiple key issues of the impacts of man-made global warming.

3. ‘I have no knowledge on those issues.’

ullstein bild via Getty Images A dead coral reef in the Maldives.

Sen. Jeff Merkley (D-Ore.) asked pointedly whether Hartnett White considers the the mass deaths of coral reefs, in events called “bleaching,” to be an environmental problem. She dithered, noting that it would be if that were true.

“I have no knowledge of those issues,” she said. “I know it is an issue but I have no specific knowledge.

MERKLEY: So scientists are telling us coral reefs are dying, and you’re saying “if” it’s happening? I mean, don’t you believe it is happening? Based on the reports from around the world? HARTNETT WHITE: I would need to read some statement of that science.

After he sparred with her over when she considers scientists worth listening to, she admitted she was “aware of the shrinking ice sheet in the Arctic but the expanding ice sheet in the Antarctic.”

That’s a frequent fact highlighted by climate change deniers as evidence that global warming is not as severe as scientists say it is. But the argument is problematic.

Sea ice off Antarctica has grown somewhat over the past decade. In September 2014, it hit a record 7.78 million square miles, the largest extent since satellites began keeping measurements in 1979, according to InsideClimate News. The outlet cited a study that found that the ocean current that determines how much sea ice grows is steered by submerged ridges and canyons along the edge of Antarctica’s continental shelf, rather than by rising temperatures or other climatic conditions.

But sea ice is just one measurement of climate change in the Antarctic. In July, an iceberg the size of Delaware broke off the Antarctic ice shelf. New research released last month found that the ocean is cutting through a key portion of the ice sheet in West Antarctica. When those ice shelves break off, they expose inland glaciers to the sea, prompting them to melt, or retreat. “These are the fastest retreating glaciers on the face of the Earth,” Eric Rignot, a glaciologist at the NASA Jet Propulsion Laboratory, told National Geographic earlier this year.

4. *Sigh*

MERKLEY: So here’s my summary: Do you believe the planet is getting warmer? HARTNETT WHITE: Yes. MERKLEY: Because it can be measured. Do you believe carbon dioxide levels have gone up dramatically? HARTNETT WHITE: [sighing audibly] No. MERKLEY: It can be measured. Scientists measure it every day. HARTNETT WHITE: No, I would not say they’ve gone up drastically. I know they have risen from pre-industrial times.

5. ‘There’s a credible difference of opinion among climate scientists.’

Senate EPW A staffer for Sen. Jeff Merkley (D-Ore.) holds up a sign citing data from the federal government's latest climate change report, released by the Trump administration.

When Merkley received another turn for questioning later in the hearing, he exhibited a poster-sized chart using data from the federal climate report released last week by the Trump administration. The report found that human-caused greenhouse gas emissions had pushed the world into its warmest period “in the history of modern civilization,” with global average air temperatures having increased by 1.8 degrees Fahrenheit over the last 115 years. The senator’s chart showed three bars, one for human emissions and the other two for volcanic activities and solar flares, which climate change deniers frequently raise as alternative theories for the cause of rising temperatures. Asked if she accepts the findings of the report, given that it was issued by the Trump administration, she said it was actually the product of the Obama administration.

“I view this report really as the product of the past administration and not of this president,” she said.

“There are all different types, there are many different types of scientists,” she added. “There’s a credible difference of opinion among climate scientists.”

Ninety-seven percent of peer-reviewed climate research concludes that greenhouse gases from burning fossil fuels, industrial farming and deforestation are the main causes of global warming. A research review released last November found significant flaws in the methodologies, assumptions or analyses used by the 3 percent of scientists whose studies found otherwise.