In a blog post yesterday climate scientist Judith Curry wrote:\n\nIt is fine for people (and scientists) have political ideologies. The problem comes in when you.use science to demand policies.\n\nIn my view, many climate scientists behave oddly compared to other kinds of experts. In criminal trials the role of expert witnesses is limited and clearly defined. They testify about their direct observations – or the results of tests they have performed.\nNot for one moment does anyone think it is the role of a handwriting expert to decide whether the accused is guilty. That is the job of the judge and the jury – after listening to a variety of experts, some of whom will no doubt contradict (and cast doubt on) each other’s opinions.\nAlthough the pathologist who performed the autopsy may have private views about an accused murderer’s guilt or innocence we all understand that it would be inappropriate for that medical professional to voice those views within the courtroom – and doubly inappropriate to do so outside of it.\nYet when it comes to climate, everything gets turned on its head. People with a narrow specialty (in water resources, for example) nevertheless regard themselves as full-fledged “climate experts.” Taking on the role of judge and jury, they imagine that an understanding of their small piece of the puzzle translates into firm knowledge of the far more complicated big-picture. They proclaim that multiple lines of evidence all point to the same conclusion – even though they themselves don’t possess the expertise to evaluate the merits of these other lines of evidence.\nIt is as if a firearms expert began declaring, while a criminal trial was still in progress, that his evidence, the testimony of the police, and the pathologist’s time-of-death estimate all point in the same direction. It’s as if that firearms expert pronounced the accused obviously guilty and urged the application of the death penalty immediately.\nJournalists would never take such behaviour seriously. They’d recognize that the expert was overstepping his mandate by a wide, wide margin. If his views got reported at all, it would be in order to expose and condemn his poor judgment.\nSo why, when climate scientists step well beyond the mandate of their narrow academic specialty and tell politicians what to do – when they “demand policies” as Judith Curry puts it – does the media think such conduct is OK?\nYesterday, the Associated Press filed exactly that kind of story, one that has since been picked up by numerous other media outlets. The mere fact that “44 scientists” from “28 Iowa colleges” have sent a letter urging politicians to respond to climate change is considered news. The Chicago Tribune report is here. An Iowa television station’s website says this. Here’s the story in a Texas newspaper.\nWe aren’t told who these scientists are, what their expertise happens to be, or why their views are more worthy of notice than the views of 44 bricklayers. We aren’t even directed to a copy of the letter. So far, I’ve not been able to locate it. Based on another news account, however, it sounds virtually identical to a letter issued by 31 Iowa academics last November (see here and here).\nAmong the alleged scientists who signed that earlier declaration is Danielle Wirth. Her PhD dissertation dealt with environmental ethics. According to her academic bio page she is affiliated with the Sierra Club, the Natural Resources Defense Council, the Environmental Defense Fund, and the Club of Rome. That makes four activist organizations – in addition to the Iowa chapter of the United Nations association. As a bonus, we read that she enjoys “herbal medicine research and preparation.”\nIt surely needs to be said that the above does not paint a picture of a rigorous, objective scientist whose opinions about climate change deserve media attention.\nAnother signatory is Thomas Rosburg, a biology professor who was the proud recipient of a Sierra Club Environmental Educator Award last October.\nA third is Mark Aronson, a zoologist whose thesis dealt with rainbow trout. He is the “chair of the Sustainable Campus Initiative Curriculum Committee for the Eastern Iowa Community College District” and the founder of a campus environmental club. The latter encourages “environmental activism and advocacy” and has formal ties with the Sierra Club, the Nature Conservancy and (here’s one I’d not heard of before) the Wildland Center for Preventing Roads.\nPersonal opinions, disguised as science, are not news. Although we’re been told that “scientists” have signed a letter in Iowa, peeking beneath the surface reveals something else. Rather than circumspect, dispassionate climate change advisors once again we discover activists.