Grijalva's letters cite recent reports of Wei-Hock "Willie" Soon, a scientist affiliated with the Harvard-Smithsonian Center for Astrophysics. Soon disputes the scientific consensus that human activities are the main driver of global warming, and documents obtained by environmentalists showed that Soon referred to his work as "deliverables" for funders.
The congressman implies that other researchers may have undisclosed relationships with fossil fuel companies. "If true, these may not be isolated incidents," Grijalva wrote.
Joanne Carney of the American Association for the Advancement of Science said she understands the concerns around Soon's work, and noted her organization requires disclosure of funding sources and potential conflicts in its journals. If the group were to find that a researcher has not disclosed the information, they would examine that author's other work, Carney said.
But she was skeptical of Grijalva's letters that probe other researchers. "I think we are questioning why they are making the assumption that other researchers need to be questioned," Carney said, and later added: "It is not clear to us why these other scientists were being targeted."
Pielke said he has "no funding, declared or undeclared, with any fossil fuel company or interest" and never has, he wrote in a blog post Wednesday. "Representative Grijalva knows this too, because when I have testified before the U.S. Congress, I have disclosed my funding and possible conflicts of interest.
"So I know with complete certainty that this investigation is a politically-motivated 'witch hunt' designed to intimidate me (and others) and to smear my name," Pielke said.
On Twitter, University of Washington earth sciences professor Eric Steig, who has battled with Pielke in the past, said that he has his back. "Welcome to the new McCarthyism. Congress should not be able to investigate on a whim. You have my *unequivocal* support," Steig said.
Mann, a prominent Penn State climate scientist who has has been subject of Republican-led probes of his work in past years, had a mixed verdict on the letters.
"It does come across as sort of heavy handed and overly aggressive," Mann told National Journal, adding that he is "a little uncomfortable" with the demands for the professors' correspondence. But he said there's nothing wrong with seeking information on funding sources. "That is something that no scientists should have any qualms" about providing, Mann said.
Mann also said the Grijalva letters on funding should not be "conflated" with probes he has faced from GOP Rep. Joe Barton and Cuccinelli.
"The difference being that they were demanding materials that are protected under principles of academic freedom—private deliberations between academics or scientists, unpublished manuscripts, raw source code that was written, stuff that's intrinsic to your work as a scientist," Mann said.