The Climate Science reference they don’t want Judges to read

For the first time, the Federal Judicial Center (FJC) commissioned a chapter on climate science for the manual they put out (with the NASEM) for judges, the Reference on Scientific Evidence (4th Edition). This week, a month after it was published, they pulled the chapter out after being pressured by 27 Republican Attorneys General. You can nonetheless read it here.

Some background. The FJC is “the research and education agency of the judicial branch of the United States Government”. As one of its roles, it is tasked to provide educational materials to judges and other court workers about issues that might come up in court, and in particular, on scientific matters that one might not expect judges or lawyers to be expert in. They have codified this information in the Reference Manual on Scientific Evidence, which is now in it’s Fourth Edition. (Previous editions were issued in 1994, 2000, and 2011).

The 4th Edition had its genesis in a workshop in 2021, and was finally published (after extensive peer review) on Dec 31st 2025. It covers legal scholarship on the use of expert testimony in court cases (noting the Supreme Court’s Daubert standard), as well as primers in the current state of the science across multiple fields (forensics, DNA evidence, mental health, neurology, epidemiology, exposure, statistics, regression, eye witnesses, engineering, computer science, AI, etc.). Notably, it included a chapter on climate science, covering topics such as the greenhouse effect, atmospheric circulation, detection and attribution, and the issues being raised in an increasing number of climate-related cases in the courts. The authors, Jessica Wentz and Radley Horton are a respected and mainstream lawyer/scientist team and the resulting chapter is a clear and concise summary of the topic. So far so good.

Of course, there are groups that would rather not have climate change discussed knowledgeably in the courts, and after the publication of the 4th Edition of the manual, the Republican-led House Judiciary Committee started sending threatening letters to all involved (FN – sorry!) (Jan 16th). Additionally, a group of 27 Republican Attorneys General (led by West Virginia) sent a letter (Jan 29) to the FJC claiming that Wentz and Horton were biased because they have (correctly) stated that the “political sphere in the United States continues to be clouded with false debates over the validity of climate change”. Additionally, they were upset that there are no references to the recent DOE CWG report (Lol).

The real target of the AGs ire is the discussion of attribution, and the notion that there is an emerging consensus that partial attribution of climate damages can be assessed on emitters. This line of thinking is exemplified by recent papers (such as Callahan and Mankin (2025), but is based on more than a decade of work on this topic, and of course is a direct threat to the fossil fuel companies that the WV AG is trying to protect.

The Republican AGs demanded that the FJC remove the chapter, arguing that any official acknowledgement of the science in the Manual would prejudice their cases that are based on, let’s say, “contrary” interpretations of the scientific evidence (or no evidence at all). And without much ado, or even consultation, the FJC did exactly that, putting out an amended Manual on Feb 6th. The only note to mark the deletion is:

No explanation or excuse was noted.

As stated above, this chapter is actually well-written, appropriately peer-reviewed, and deserves a far better fate than to be cowardly disappeared into a memory hole for being inconvenient, so you can download it here. The nice thing about science is that it doesn’t change based on whether a report is published here or there, so feel free to share.

References

1. C.W. Callahan, and J.S. Mankin, "Carbon majors and the scientific case for climate liability", Nature, vol. 640, pp. 893-901, 2025. http://dx.doi.org/10.1038/s41586-025-08751-3