The Biden administration has reinstalled the director of the federal climate program that produces the U.S. government’s definitive reports on climate change after he was removed by the Trump administration in November.

Michael Kuperberg, the climate scientist who ran the program for six years until he was reassigned, returned on Monday, the White House confirmed.

As the executive director of the U.S. Global Change Research Program, Kuperberg coordinates climate change research across 13 federal agencies and production of the program’s National Climate Assessment, the nation’s most important report on climate change science and its consequences.

“I’m really excited to be back,” Kuperberg said in an interview, calling the timing of his return “perfect” considering the Biden administration’s emphasis on global warming. “I think [the program] is a critical component for advancing the climate agenda of this administration. It’s been around a long time [and] we’ve spent a lot of money on basic research. We have an opportunity to put that science to work in informing decisions on our response to climate change.”

When he was exiled from his post and reassigned to the Department of Energy in November, Kuperberg said he was “surprised” but knew it was a possibility since he served at the discretion of the administration. “It’s their prerogative to make those kinds of changes,” he said.

Now that he’s back, Kuperberg stressed that he sees his job responsibilities as nonpartisan. “We’re coordinating science and we’re trying to get to the nation the very best possible science,” he said. “This is not politics.”

Jane Lubchenco, who oversees the research program as the White House Office of Science and Technology Policy lead climate official, praised Kuperberg’s ability to work across the political spectrum.

“Dr. Kuperberg has earned the trust of the science community and policymakers regardless of party stripes,” Lubchenco said in a news release.

In a letter to Kuperberg written Tuesday, Lubchenco called on him and the program “to accelerate action on two fronts-advancing science to increase our knowledge, especially on societally relevant topics, and ensuring that knowledge is understandable, accessible and useable to the key stakeholders.”

“We are at a critical juncture,” she wrote. “Smart action, informed by science, is paramount. The role of [the program] has never been more important.”

Kuperberg’s ouster in the fall came as the Trump administration elevated scientists who questioned the seriousness of climate change to lead the program. It was an apparent effort to seize control of the report’s scope and direction, in case Donald Trump won re-election.

Under Kuperberg’s leadership, the research program had released the fourth edition of the climate assessment in 2018, detailing the severe consequences the U.S. would face if it takes little action to cut emissions and prepare for climate change’s effects.

The report, produced by federal and independent scientists, angered White House officials because Trump consistently downplayed the seriousness of the climate threat and the scientific consensus that human activities are playing the dominant role in warming the planet.

Trump officials placed David Legates, a National Oceanic and Atmospheric Administration appointee from the University of Delaware who cast doubt on mainstream climate science findings, into Kuperberg’s position. Legates was assisted by Ryan Maue, NOAA’s chief scientist, also known for contrarian viewpoints on the issue.

During their brief tenure leading the research program, Legates and Maue helped produce documents that challenged the validity of key climate science findings. The papers, which were not peer-reviewed and bore the seal of the Executive Office of the President, angered then-White House science adviser Kelvin Droegemeier, who had not approved the effort. Droegemeier relieved the scientists of their duties and they resigned from the government days later, just before President Joe Biden’s inauguration.

Kuperberg now faces the challenge of producing the fifth edition of the National Climate Assessment, by the end of 2023, having lost more than six months since his removal. But he said work on the project continued in his absence and he expressed confidence that it will be completed in time.

“We’re not starting from zero,” he said. “It is moving forward. I’m very pleased with that. We’re going to put out a document that we can stand behind and be proud of.”

One of Kuperberg’s first actions will be to find a new person to lead the assessment.

Betsy Weatherhead, the atmospheric scientist selected by Droegemeier to lead the report, was reassigned by the Biden White House in April to the U.S. Geological Survey. Kuperberg said he’s working with the White House to identify Weatherhead’s replacement.

Kuperberg said he wants the next report to build from previous efforts.

Early editions of the assessment were thick, hard copy volumes that have since evolved into rich multi-media websites. He sees the fifth edition as a “dynamic resource” with customizable datasets that reach new audiences. “Everybody from farmers, transportation managers, energy producers and citizens in small and large cities will face challenges from climate change,” he said. “We want to put information in their hands to respond to those challenges.”

Former program officials and agency leaders lauded the Biden administration’s decision to bring Kuperberg back.

“Mike is a humble leader, respected by his agency peers; you’d be hard-pressed to identify a civil servant more prepared to steward [the program] in this time,” wrote Dave Reidmiller, who led the fourth edition of the climate assessment and is the director of the Climate Center at the Gulf of Maine Research Institute, in an email. “He not only has the knowledge of how to get things done through the interagency process, but also a keen understanding of the research needed to underpin aggressive, equitable climate solutions.”