As the rest of the world’s governing bodies and opinion polls have gradually come around to a consensus on climate change, the United States stands out as a particularly odd outlier: Supporters and deniers here have in fact grown further apart, with the issue more politically divisive today than it was just five years ago. Public concern about the climate has actually declined. Politicians who once acknowledged global warming have changed their minds. And in a particularly shocking vote earlier this spring, not one of the 31 Republicans on the House Energy and Commerce Committee would vote for an amendment simply acknowledging that climate change exists (which is the position of the government’s own scientific bodies).

In the midst of all this, an even stranger thing has happened — scientists themselves have become controversial figures, now routinely harassed, investigated and attacked for their research.

In a particularly high-profile case, Virginia’s elected attorney general has spent most of the past year trying to subpoena the state’s prestigious public university for the academic records of a climate scientist, Michael Mann, whom he accuses of defrauding the public for grant money to support his research. Mann has not worked at the University of Virginia since 2005.

The latest tactic, inspired by the Climategate email scandal, has been for non-governmental activist groups to file public records requests about individual researchers in the hunt for personal information to discredit them. One such group, the American Tradition Institute, last week sued NASA to obtain records on any ethics or disclosure violations by James Hansen, a top climatologist who blew the whistle on censorship of scientists during the Bush Administration.

The trend is distressing for each of the researchers who’ve become unwitting targets. But, more broadly, academic and scientific organisations increasingly worry that such tactics will have a much wider impact — intimidating the entire scientific community and deterring work on a crucial area of public inquiry.

Exasperated with this trend, one of the country’s most respected scientific organisations (and the world’s largest general scientific body), this week released a formal statement decrying all the harassment. The board of the American Association for the Advancement of Science wrote:

“We are deeply concerned by the extent and nature of personal attacks on climate scientists. Reports of harassment, death threats, and legal challenges have created a hostile environment that inhibits the free exchange of scientific findings and ideas and makes it difficult for factual information and scientific analyses to reach policymakers and the public. This both impedes the progress of science and interferes with the application of science to the solution of global problems. AAAS vigorously opposes attacks on researchers that question their personal and professional integrity or threaten their safety based on displeasure with their scientific conclusions.”

The scientific community has spent centuries perfecting the process of policing itself — peer review is designed to ferret out research fraud, and the revision and correction of earlier findings is a central element of the very idea of scientific progress.

All of this has been lost on aggressive climate deniers, who have been remarkably successful at creating the public impression of scientists as agenda-wielding partisans in a political war. For their part, cloistered researchers not used to communicating with the public have seemed baffled by attacks that can’t be repelled on data and evidence alone.

As the AAAS points out, the stakes go beyond even the implications for chilled speech. Because all of society will lose out when scientists are intimidated into staying away from climate research that’s needed to inform what we should do about the problem.

As the board put it:

“We are concerned that establishing a practice of aggressive inquiry into the professional histories of scientists whose findings may bear on policy in ways that some find unpalatable could well have a chilling effect on the willingness of scientists to conduct research that intersects with policy-relevant scientific questions.”