A little less than seven years ago, the climate scientist Michael Mann ambled into his office at Penn State University with a wedge of mail tucked under his arm. As he tore into one of the envelopes, which was hand-addressed to him, white powder tumbled from the folds of the letter. Mann recoiled from the grainy plume and rushed to the bathroom to scrub his hands.



Fortunately for Mann, the FBI confirmed the powder was cornstarch rather than anthrax. It was perhaps the nadir of the vituperation hurled at Mann by often anonymous critics who accuse him and others of fabricating or exaggerating the dangers of climate change.

“Michael has most certainly become a lightning rod,” said Kerry Emanuel, an MIT climate scientist, although this doesn’t mean others have been shielded.

Emanuel himself has previously received emails threatening him and his family. The Texas Tech University professor Katharine Hayhoe, who has gathered a healthy following for her Facebook posts that mix climate science with evangelism, has opened her inbox to missives including “Nazi Bitch Whore Climatebecile” and a request that she “stop using Jesus to justify your wacko ideas about global warming”.

Threats and badgering of climate scientists peaked after the theft and release of the “Climategate” emails – a 2009 scandal that was painfully thin on scandal. But the organized effort to pry open cracks in the overwhelming edifice of proof that humans are slowly baking the planet never went away. Scientists are now concerned that the election of Donald Trump has revitalized those who believe climate researchers are cosseted fraudsters.

Mann said climate scientists “fear an era of McCarthyist attacks on our work and our integrity”. The odd unfulfilled threat may be perturbing but a more morale-sapping fear is that the White House and Congress will dig up and parade seemingly unflattering emails, sideline or scrap research and attempt to hush the scientific community.

“I faced all of those things a decade ago, the last time Republicans had full control of our government,” said Mann, who has been pursued on and off since 2010 when Virginia’s then attorney general, Ken Cuccinelli, unsuccessfully demanded that the University of Virginia hand over all of Mann’s correspondence to see if he had obtained grants fraudulently. The American Tradition Institute, a free-market thinktank, followed up with a records request for the same correspondence.

After several years fending off these claims, Mann decided to wade into a fight with the National Review, a conservative publication, and the Competitive Enterprise Institute, another free-market group. Mann’s lawsuit states that “false and defamatory statements” accused him of academic dishonesty and compared him to a convicted child molester, the former Penn State assistant football coach Jerry Sandusky.

“I don’t think Michael is doing this happily, but he views it as vital to stand up to those who undertake personal attacks,” said Peter Fontaine, Mann’s lawyer.

Fontaine expects climate scientists will have to deal with attacks from a range of powerful foes in the coming years. “If you believe climate change is a hoax perpetrated by the Chinese, as Donald Trump does, you will go after anything that opposes that view,” he said. “A lot of people will be hung out to dry.”

The Climate Science Legal Defense Fund, which was set up in 2011 and has assisted Mann and other scientists from attempts to access their emails, deals with half a dozen such cases a year, give or take. It expects a busier 2017.

“We are hearing from scientists every week who are worried about what is going to happen,” said Lauren Kurtz, executive director of the fund. “Now Trump is in charge, who knows how the federal agencies will react, if they will understand that they have to protect scientists.

“Trump himself is a bully and has emboldened a whole trove of people who have become bolder and meaner. That includes those who will target climate scientists. I’ve spoken to a scientist who received a death threat and is concerned it will happen again.”

Kurtz and her small team, housed at Columbia University, are currently siding with the University of Arizona against a demand it release more than a decade’s worth of emails from two of its climate scientists, Malcolm Hughes and Jonathan Overpeck.

The records request has come from Mann’s former tormentors the American Tradition Institute, now rebranded as Energy & Environment Legal Institute, a group that promotes “free market environmentalism”. It has previously sued Nasa to reveal the extracurricular income of its former scientist James Hansen, whom E&E calls the “original climate alarmist”.

E&E’s University of Arizona demand includes all of Hughes’ correspondence with Mann over a six-year period. The two were research partners on the famous “hockey stick” research that outlined the steep climb in global temperatures after humankind began belching emissions from mass industrialization.

In an apparent bid to bolster a case that research has been rushed out to artificially prop up the global warming theory, E&E is also seeking all of Overpeck’s emails that include the word “deadline”. This voluminous request will involve digging through hard drives in dusty basements. In June last year, an Arizona trial judge ruled that the emails must be turned over.

‘The administration’s disdain towards climate science has prompted some climatologists to consider leaving the profession.’ Photograph: Rex/Shutterstock

The case, and others like it, hinges on the question of how public publicly funded institutions should be. Various conservative groups – as well as news outlets including the Washington Post and AP – have argued scientists should be subject to full freedom of information laws, meaning their emails are fair game. Universities and their researchers insist that academic freedom would be stifled by requests that could quickly morph into witch-hunts.

In his court submission, Overpeck said the time taken to respond to E&E’s request wiped out his sabbatical, accusing the group of wanting “to burden, embarrass, or harass climate researchers such as myself”.

Several climate scientists have reported becoming far more careful about what they say in emails, in case a “smoking gun” be construed from them. Funding applications are light on mentions of climate change, even when it is the research topic. The arrival of an administration considered disdainful of climate science has even prompted some climatologists to consider leaving the profession in fear of funding cuts.

“The uncertainty unsettles the staff, and some are more vulnerable than others,” said Kevin Trenberth, a climate scientist who has been at the US National Center for Atmospheric Research since 1984. “If graduate students look for careers in other areas, suddenly you have a gap where no good young scientists are replacing ones who are retiring.

“Many people are adopting a wait-and-see strategy with Trump. But those who have to make decisions on their careers are looking more widely than they would have done before.”

Nasa’s satellites are still orbiting the Earth and checking on its fever, while government scientists are still measuring the acidification of its oceans and charting the extent of its glaciers. But reports of a gag order on Environmental Protection Agency scientists and a cabinet dotted with those who dismiss mainstream climate science has made researchers jittery about the future of such research.

Some of the EPA’s climate information has been altered, although an expected purge has yet to materialize. In an internal video message, Catherine McCabe, the interim EPA administrator, said she wanted to “allay fears and rumors” among staff by reassuring them that the modifications were “ordinary housekeeping changes that have been made by EPA career employees”.

Fretful researchers believe more is afoot, assembling a volunteer group that has set about archiving climate data and monitoring federal agencies for deletions. The enterprise, called the Environmental Data and Governance Initiative, was set up the day after Trump’s election triumph and is indexing 150 climate-related domains. Archiving events, open to volunteers, will take place every other day over the coming month.

“We are hearing a real sense of despair from people at federal agencies,” said Rebecca Lave, who volunteers for the project aside from her role as associate professor of geography at Indiana University. “There’s a sense that quite drastic things can happen even in democratic societies. The US isn’t immune to that.”

As scientists await the Trump administration’s next move, congressman Lamar Smith has barreled onwards in his personal crusade to uncover nefarious practices by climate scientists. Smith, a Republican from Texas, is so enthused by Trump that he recently advised the American public to get its news directly from the new president as it was “the only way to get the unvarnished truth”.

In February, Smith, chairman of the House science committee, further flattered the new administration by holding a hearing called “Making the EPA great again”. Despite the title of the hearing, Smith’s main target was the National Oceanic and Atmospheric Administration (Noaa), which he said had “deceived the American people by falsifying data to justify a partisan agenda”.

In 2015, Smith claimed that “climate alarmists have failed to explain the lack of global warming over the past 15 years” (despite the fact 14 of the 15 warmest years on record at that point had occurred since 2000) and subpoenaed Noaa to produce every single email sent by an agency scientist that included words such as “climate” and “temperature”.

Two days before the “Making the EPA great again” hearing, Smith was blessed with what he believed to be vindication – a Daily Mail story that claimed Noaa manipulated temperature data to hide a warming “hiatus” and rushed out the research in order to help convince countries to sign the Paris climate deal in 2015.

The purported whistleblower rebuffed the central claims of the story, while scientists were quick to point out that several separate studies have shown there has been no real pause in warming. Andrew Light, a chief US negotiator in Paris, said it is “ridiculous” to posit nearly 200 countries were waiting for one crucial study before agreeing to cut greenhouse gas emissions.

But the House committee’s embrace of the Daily Mail story – it devoted nearly a dozen tweets to the allegations – indicates that agencies such as Nasa and Noaa will be under the microscope with uncertain levels of support from the administration that oversees them.

The pursuers contend that climate scientists deserve the scrutiny given the gravity of their findings – the future livability of the planet – and their salaries drawn from the public purse. Judicial Watch, a conservative group, is suing Noaa for thousands of internal communications previously denied to them because they fall under “deliberative process” – discussions that take place before a final decision.

“There has been scandal after scandal involving climate data and we are skeptical of government agencies that won’t tell people what they are up to,” said Tom Fitton, president of Judicial Watch.

“The gig is up for the left who are hiding behind government obstruction. There has been a politicization of the science. I’m sure scientists are concerned that funding for dubious research will be cut, but the truth will win out in the end.

“We hope we won’t get the same obstruction we got from the Obama administration under this new administration. We’ll see.”

While the legal challenges wind their way through the courts, perhaps the best climate scientists can hope for is that the venom seen after Climategate has seeped into other nooks of public life. The flash points for the Trump administration are coalescing around immigration and the president’s persona. Climate science may become a secondary fight.

“I think the chaos of the transition will settle down and the administration will realize that attempts to muffle scientists usually backfire terribly,” said MIT’s Emanuel, who identified as a Republican until 2006. “The country is polarized on so many things that are much more immediate, like abortions. Climate is down the list of things people want to squabble about.”

“I think we are in a mild state of shock after the election. Politics has been turned upside down and all of these dark forces have erupted. Climate science may well take a back seat to all of that.”