Other conservatives in Congress took aim at climate researchers well before the 2016 election. Representative Lamar Smith, a Texas Republican who is chairman of the House Science Committee, last year subpoenaed federal climate scientists whose work supporting the evidence of a warming planet shows what he has called a “suspect climate agenda.”

Actions by the Trump administration have been met with anger, lawsuits and friend-of-the-court briefs. A group of former Obama administration lawyers has filed lawsuits seeking information about charges of bullying of civil servants and scientists who work on climate issues.

David M. Uhlmann, a law professor at the University of Michigan and a former top prosecutor of environmental crimes at the Justice Department, has taken part in several such efforts, including briefs filed before Mr. Trump took office. He said the work was important both as an attempt to preserve environmental progress and as a message to his students.

In November, many of his students expressed dismay over the election results “and their concern that everything they came to law school for no longer mattered,” Professor Uhlmann said. “My message to them was, ‘Everything you came to law school for matters more than ever before.’”

Other lawyers are stepping up to protect dozens of climate scientists who have been targeted by private conservative groups demanding their personal emails and other documents. The groups, which dispute the powerful evidence underlying climate change science, use the tactic to unearth embarrassing and inartful language in private correspondence and then publicize it.

Those filing the document requests say they are trying to ferret out politicized, sloppy science and fraud. David Schnare, an official at the Energy and Environmental Legal Institute, said, “The legislatures give the citizens a right to know, and for good reasons — and there are good reasons for citizens to find out what’s going on.” Mr. Schnare, who was a longtime E.P.A. employee, briefly served in the Trump administration’s transition team at the agency; the group receives funding from the fossil fuel industry.