Under pressure from Republican state attorneys general, the agency that advises the U.S. Supreme Court and federal judges on scientific and technical matters has withdrawn the entire climate change content from a new judicial reference manual.
The Federal Judicial Center’s move leaves judges without formal help on how to weigh basic weather and climate change evidence, just as numerous climate-related cases are making their way through state and federal courts, including two on the U.S. Supreme Court’s docket this session.
The center was established as an educational institution and is headed by Chief Justice John Roberts. By law, it is responsible for overseeing court policy and investigating technical and scientific issues raised before the court. The Supreme Court’s press office did not respond to requests for comment.
On December 31, 2025, the Center released the first updated version in 15 years of a 1,682-page peer-reviewed guide called the Reference Manual on Scientific Evidence. The guide has more than 90 pages of definitions of climate terms, the state of scientific consensus on climate change, and the methods used to attribute certain weather phenomena to climate warming and its causes. This chapter acknowledges the uncertainties in some areas of climate science. This typically reflects the conclusions of the United Nations’ Intergovernmental Panel on Climate Change.
Widely cited and trusted by law clerks and judges, the manual was developed in collaboration with the National Academies of Sciences, Engineering, and Medicine, and also includes chapters on artificial intelligence, DNA testing, and epidemiology, among other subjects. This book is considered one of the most important and reliable guides for judges working on technical content, mainly because it has been approved by the judicial branch itself.
But the inclusion of the climate change chapter immediately drew criticism from conservatives, who say it is slanted against oil and gas producers and represents an effort by activists to sway the opinions of the judges hearing the current case.
The withdrawal comes amid a slew of lawsuits holding oil and gas companies accountable for damages caused by climate change, which is scientifically linked to emissions produced by burning fossil fuels. Republican attorneys general have repeatedly criticized these cases, accusing liberals of using tort law to enact regulatory policies and supporting efforts to dismiss or move cases to federal court.
On February 2, more than 20 Republican attorneys general sent a letter to the House and Senate Judiciary Committees saying the manual was “tainted by biased authors, reviewers, and sources involved in ongoing litigation” and an “improper attempt to falsify the outcome of a case in favor of one side.” The group encouraged the House Judiciary Committee, chaired by Ohio Republican Jim Jordan, to include the publication in a recently released study by the Environmental Law Institute, a bipartisan research group, on programs to educate judges about climate change.
The next day, the Federalist Society, a conservative judicial group, convened a committee to discuss publication of the manual. The moderator said this contradicted the Federal Judicial Center’s role as a “neutral arbiter of facts” and warned that “creating a climate science section advances an ideological agenda.”
The chapter reflects “the assumption that certain evidence is automatically more reliable than other evidence,” West Virginia Attorney General Michael Williams told the committee audience. It suggests that “certain issues will be resolved while litigation continues in actual court.”
On February 6, Judge Robin Rosenberg of the Southern District of Florida, director of the Federal Judicial Center, sent a letter to West Virginia Attorney General John McCaskey saying the center had “omitted the climate science chapter.”
In a letter last week, the attorney general expressed concern that one of the authors of the climate chapter was employed by Columbia University’s Sabin Center for Climate Change Law and that in a footnote to the report, the authors thanked the program’s executive director, Michael Berger. Berger, who declined to comment, is an attorney at the law firm Schar Edling, which represents several plaintiffs in climate change lawsuits, including the city of Honolulu.
Jessica Wentz, one of the chapter’s authors, said the state attorney general’s objection was “ultimately a disingenuous criticism aimed at suppressing scientific information.” Retracting the chapter “will be used to advance this narrative that even the most basic aspects of climate change are in dispute,” she said.
Wentz said he has never been a witness or served as an attorney in a climate change case and said it would be disingenuous for him as attorney general to challenge the climate change chapter, which acknowledges the consensus that human activity causes global warming, because it is the subject of a pending lawsuit. None of the big climate lawsuits she knows of discuss the science of global warming, instead focusing on questions about the liability of fossil fuel companies. “The injection of bias comes not from exposure to scientific information, but from the suppression of that scientific information,” Wentz said.
Although the Federal Judicial Center removed the version that included the climate change chapter from its own manual, the National Academies of Sciences, Engineering, and Medicine maintains a copy of the original manual on its own website. A representative for the center declined to comment, and members of the House Judiciary Committee were not immediately available for comment.
