Editor’s Note

On March 2, some scientists who had contributed to the Fourth Edition of the Reference Manual on Scientific Evidence (co-produced by the Federal Judiciary Center and the National Academies of Sciences, Engineering, and Medicine) published an open letter in Science Politics objecting to the removal of a chapter on climate science. 

One of the people advocating for the chapter’s removal accepted our invitation to respond. West Virginia Attorney General John B. McCuskey makes his argument below.

McCuskey’s Response

The Reference Manual on Scientific Evidence isn’t intended to give a leg up to litigants with a  particular point of view. And it shouldn’t push political agendas on the judiciary. 

But that’s exactly what the climate science chapter did. So 27 attorneys general — all committed  to defending the rule of law — called out the climate science chapter for what it is: politics masquerading as scientific consensus. 

The Federal Judicial Center was right to pull the chapter. 

To respond directly to the Manual’s other authors (“the signatories”), let’s start with where we  agree. 

We agree that federal judges must decide whether scientific and technical expert testimony is reliable enough for a jury to hear. 

We also agree that the Manual shouldn’t instruct judges to reach certain results. 

And we agree the judiciary’s impartiality is paramount. 

Those are the exact reasons we requested the climate science chapter’s removal.  

In their open letter, the signatories invoke Chief Justice Rehnquist to say the Manual doesn’t  instruct judges to admit or exclude any particular evidence. We agree with that sentiment, too.  

But the climate science chapter does instruct judges to admit certain evidence and exclude other  evidence. 

For instance, the climate science chapter tells judges how to gauge evidence’s reliability. The  chapter’s authors proclaim what evidence is best. They say Intergovernmental Panel on Climate Change (IPCC) assessments should be afforded more weight than other studies and reports. But weighing credibility is for judges  and juries, not scientists with a political bent. 

The authors also say judges shouldn’t worry about whether studies are peer reviewed so long as “the findings are consistent with those from expert bodies like the IPCC.” That instruction flies in the face of federal courts’ long followed Daubert standard, which requires judges to consider not only experts’ reputations, but methodology and scientific principles.

The signatories also applaud the Manual’s “independence and objectivity,” but the climate  science chapter ignored a swath of contradictory evidence. Following the chapter’s authors’ view  that the IPCC is the untouchable gold standard, they don’t even mention experts’ attacks on the  IPCC’s work. And some of that criticism is levied by our own government. 

To be sure, the chapter’s authors recognize “the  science is constantly evolving,” so they would permit IPCC criticism if — and only if — it came after the IPCC published its most recent report. 

Put another way, the authors will allow courts to consider contrary studies if the IPCC hasn’t had a chance to debunk them yet. In their view, the IPCC may be late, but it’s never wrong. 

So the chapter’s authors tell judges to afford most weight to the IPCC, admit non-peer reviewed studies if they are consistent with the IPCC, and pretend no scientists criticize the IPCC’s methodologies or conclusions. 

There’s nothing independent or objective about IPCC sycophancy.  

What’s more, the climate science chapter tells judges what the law is. The chapter’s authors spill  considerable ink telling courts about “different types of climate lawsuits,” the “contours” of causation analysis in those cases, and even how Supreme Court cases support attribution science  and its application to damages claims.  

The signatories don’t explain how they peer reviewed these legal conclusions. 

If that weren’t enough, the chapter’s authors tell courts what conclusions to reach. Without addressing any contrary evidence, they declare attribution methodology “unequivocally” established. 

They lay out a three-step framework for courts to find causation. 

And they tell judges to trust experts “quantify[ing] the contribution of anthropogenic forcing to  specific damages, harms, and economic and noneconomic losses.” 

So the chapter’s authors tell judges how to answer ultimate liability and remedy questions, too. 

None of these issues is surprising. The chapter’s authors, Jessica Wentz and Radley Horton, have written (along with a climate plaintiffs’ attorney) in support of climate-lawsuit plaintiffs. 

And one of the chapter’s authors has even encouraged filing such suits. Again, if “independence  and objectivity” is the goal, the signatories backed the wrong horses. 

The signatories’ concerns are misplaced. 

They should be concerned that the climate science chapter was published in the first place. 

They should be concerned that the biased climate science chapter mars their own published scientific work. 

They should be concerned that the National Academy is watering down the scientific process by ignoring contrary evidence. 

And they should be concerned that one-sided political theater and legal case explainers passed what they call an “extensive and rigorous peer review.” We would welcome the peer review team’s explanation of how they went about verifying the chapter’s authors’ take on Massachusetts v. EPA. 

There, the Supreme Court narrowly decided that greenhouse gases fit the Clean Air Act’s broad definition of “air pollutant.”  So the Court said the Environmental Protection Agency had to “decide whether greenhouse gases cause or contribute to climate change.” But the Court didn’t instruct EPA to make any particular finding. 

The climate science chapter takes this case about statutory interpretation and regulatory authority and twists it into an affirmative argument in support of damages claims in climate litigation.  Regardless of the chapter’s authors’ slant on this or any other case, one thing is clear: None of this discussion is about science.

The climate science chapter isn’t science at all. It’s a litigation playbook (complete with  case law) packaged as settled scientific consensus. 

The climate science chapter is an affront to the scientific community. The signatories should be demanding that the National Academies of Sciences, Engineering, and Medicine retract its publication.