Update (Feb. 1, 9:52am): This story has been updated with a comment from a Trump-appointed US Department of Commerce official, who claims Haapala never participated in transition meetings, despite his ties to the transition team. The headline has been updated to reflect this information.

The US National Oceanic and Atmospheric Administration is home to the world’s largest repository of climate data.

It houses data from the United States and from other countries, many of which rely on NOAA’s archives to understand everything from the shifting global climate, to the health of fisheries, to ocean chemistry, to the paleoclimatic record—including million-year-old tree rings. NOAA’s information also figures into the daily lives of Americans perhaps more than any other agency; if you’ve checked the weather forecast lately, you can thank NOAA. And perhaps most importantly, NOAA’s records serve as the backbone of scientific evidence of human-induced global warming.

“The archive spans data that goes well over a hundred years,” Scott Stephens, a NOAA meteorologist, tells Quartz. “Especially for the US, there’s data that goes back almost to Independence.”

But during the Trump transition, that was in the hands of Kenneth Haapala, selected by US president Donald Trump to serve on the team that helps appoint top administrators at NOAA. Haapala served on the transition team for the US Department of Commerce, which oversees the agency. He is also an unabashed climate-change denier.

A senior Department of Commerce official appointed by Trump called us after this story was first published, to distance the department from Haapala. “He has never been an employee at the Commerce Department, has never been a member of the beachhead team, and never participated in Commerce Department transition meetings,” the official said. The “beachhead” team is the team of Trump appointees that serve as federal employees for a temporary period after inauguration. The transition team is separate from the beachhead team. The official was unable to clarify when Haapala stopped officially serving on the transition team.

Haapala is a policy expert at the Heartland Institute, a conservative group that has equated belief in climate change with terrorism and mass murder. The group devotes significant resources to promoting the false claim that there not a scientific consensus on climate change, and that, according to its website, “Most scientists do not believe human greenhouse gas emissions are a proven threat to the environment or to human well-being,” which is also false.

Heartland has also worked to influence public school curriculums away from teaching about climate change as a man-made reality. The group has been financed in part by donations from foundations tied to Koch Industries, a major oil refiner.

Sen. Sheldon Whitehouse (D) of Rhode Island and Arizona Rep. Raul Grijalva (D) wrote a letter to Trump last week, opposing Haapala’s appointment and citing his work downplaying the threat of sea level rise, the Huffington Post reported.

“We urge you to remove Mr. Haapala and any others who share his discredited views on climate science from the DOC landing team. He certainly does not understand or appreciate NOAA’s mission and therefore is unfit to serve in any capacity that oversees operations or personnel decisions at the agency,” the congressmen wrote.

Haapala will help choose NOAA’s leadership once the Senate votes on billionaire investor Wilbur Ross, Trump’s choice for secretary of commerce. Ross pledged during his confirmation hearing to support NOAA’s scientific research and advocate that it continues to be accessible to the public.

“If confirmed, I intend to see that the Department [of Commerce] provides the public with as much factual and accurate data as we have available. It is public tax dollars that support the Department’s scientific research, and barring some national security concern, I see no valid reason to keep peer reviewed research from the public,” he said. “To be clear, by peer review I mean scientific review and not a political filter.”