Perhaps it was to be expected. Just days after documents surfaced that raised conflict-of-interest questions about the funding sources of noted climate sceptic Willie Soon, a member in the US House of Representatives entered the fray. On 24 February, Raúl Grijalva, the leading Democrat on the House Committee on Natural Resources, released letters that he had sent to seven universities demanding information on the funding sources of seven other scientists whose views he does not appreciate. Grijalva was right when he wrote in the letters that conflicts of interest “should be clear to stakeholders”, but his investigation sends all the wrong messages.

Somewhere behind Grijalva’s motives there is a legitimate point. Scientists have a responsibility to disclose their funding sources and any other ties that could be perceived as conflicts of interest when they publish their work. Institutions, including the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts, where Soon works, must establish policies that lay out the rules for their researchers. Scientific journals must also ask authors to declare possible conflicts. These disclosures should apply to funding from industry and from foundations, regardless of which way they lean, as well as from environmental groups. Where there is evidence that these standards are not being met, there is certainly scope to investigate why.

As a result of documents obtained through a US Freedom of Information Act and released last month by environmentalists, the CfA is now reviewing Soon’s case and its own policies (see Nature http://doi.org/2jx; 2015). This is as it should be, but Grijalva’s inquiry is a fishing expedition that seems to have been crafted for publicity rather than clarity. Among his targets are a few long-time climate sceptics, such as Richard Lindzen at the Massachusetts Institute of Technology in Cambridge. Also on the list are policy researcher Roger Pielke Jr at the University of Colorado Boulder, whose ‘sin’ has been to question political convention on climate issues, and Judith Curry, a climate scientist at the Georgia Institute of Technology in Atlanta who has engaged with climate sceptics.

“Politicians are singling out researchers with whom they disagree.”

All of the researchers have testified before Congress, and Grijalva says that his goal is to maintain public confidence in public institutions by ensuring that public policies are not improperly influenced by outside money. Unfortunately, he laments, congressional disclosure requirements did not compel researchers to report their sources of funding, and “we need to fill in those gaps”. His letters are addressed to the presidents of the researchers’ universities and request information about financial disclosure policies, sources of external funding and any formal disclosures of such funding. They also ask for all drafts of public testimony that the researchers “helped prepare for others” and any communications about the preparation of testimony.

Not only does this investigation shine a high-profile light on researchers before the evidence to judge them has even been gathered, but it goes well beyond questions about funding and disclosure by seeking early testimony drafts and personal correspondence. (Grijalva admitted earlier this week that this was an “overreach”, although he is letting his requests stand for now.) A spokesman for Grijalva and the committee’s Democratic minority sought to distinguish between this investigation and a 2005 episode in which former chairman of the House Energy & Commerce Committee Joe Barton (Republican, Texas) requested personal communications and scientific data on palaeo­climate research from scientists including Michael Mann, now at Pennsylvania State University in University Park. Grijalva is not seeking scientific data, but there is a reason for the comparison. In both cases, politicians are singling out researchers with whom they disagree and are seeking access to private deliberations that should be protected in the name of academic freedom.

Scientists must view their funding sources as public information that is always subject to scrutiny, and act accordingly. But when politicians seek to probe beyond possible sources of external influence on published work and attempt to expose internal discussions that they find inconvenient, that sends a chilling message to all academics and to the wider public.