Then-Canadian Prime Minister Stephen Harper and his wife, Laureen, wave to the crowd during a campaign stop in 2015. Scientists complained of censorship during his administration. (Jonathan Hayward/The Canadian Press via Associated Press)

The Environmental Protection Agency's once-prolific Twitter account has not stirred since Inauguration Day. Neither has its blog, where staff used to write often about the agency's research, regulations and “Why Science Matters” — as one of the last entries put it.

Both have been dark since President Trump took over the White House, not long after telling a reporter “nobody really knows” whether Earth's climate is changing. His administration almost immediately moved to restrict scientific departments across the federal government from talking to the media and the public.

White House officials have denied trying to censor public research bodies. Their counterparts in Canada denied the same several years ago — as scientists in that country reported that government minders were following them around, listening in on them and threatening them for speaking out of turn in public.

Now, some who worked in government during former prime minister Stephen Harper's years in power are warning Americans to expect their own regime of censored science.

“In Harper’s era, it was open warfare with the media,” Max Bothwell, an environmental scientist for the Canadian government, told Smithsonian Magazine. “I suspect something similar is about to happen in the U.S.”

Bothwell, who specializes in the seemingly apolitical study of rock algae, told the outlet about a local radio station's request to interview him in 2013.

He said he had to ask permission through an array of “media control” bureaucrats that Harper had installed.

He got it, under one condition: “Unbeknownst to the Canadian radio listeners, the media control staffers would be listening in on the phone line, as well,” Smithsonian wrote. Bothwell refused.

The Canadian Press also proved unable to interview the algae scientist. An investigation by the CBC discovered why: "110 pages of emails to and from 16 different federal government communications operatives” about the interview request, some of which referred to “agreed answers” and scripts that Bothwell may have been forced to repeat.

The CBC speculated that a single line in Bothwell's algae notes — “blooms are the results of global climate change factors” — provoked the pushback. Harper was a proponent of Canada's oil sands industry, which like other fossil fuel activities, is linked to climate change.

But scientific interference went beyond media relations, other researchers said.

An Arctic biologist, Ian Stirling, told Smithsonian that government minders escorted him and his colleagues to a conference in 2012 — to “listen to them speak to other scientists and track which research posters they read.”

Threats for disobedience could be severe in the latter years of Harper's administration — even on matters of seemingly little importance.

Steven Campana, a scientist in Canada’s Department of Fisheries and Oceans, told Smithsonian about the time he gave an unapproved TV interview about a great white shark.

His comments earned him a letter of discipline “and a threat of severe punishment upon a second infraction,” the outlet reported.

“We basically were prevented from actually doing any science,” he said.

Bothwell, Campana and Stirling's complaints were backed up by many others. “A study by the Professional Institute of the Public Service of Canada found that 90 percent of government scientists felt that they could not speak freely about their work,” The Washington Post's William Marsden once wrote.

Likewise, more than 800 scientists from around the world sent Harper an open letter in 2014, warning that “Canada’s leadership in basic research, environmental, health and other public science is in jeopardy.”

Canada's information commission eventually launched a censorship investigation into the complaints.

It had not concluded before late 2015, when Harper lost to Prime Minister Justin Trudeau, who restored scientists' rights to speak directly to the public, the Smithsonian reported.

President Barack Obama did something similar — ordering a “scientific integrity” policy when he took over the White House from President George W. Bush, who had restricted public access to research on climate change, according to The Post.

Even even before Trump took office, The Post's Brady Dennis wrote, scientists began “a feverish attempt to copy reams of government data onto independent servers in hopes of safeguarding it from any political interference.”

So far, there has been no sign that officials have destroyed any data, but multiple censorship attempts have been reported during Trump's first days in office.

EPA staff were told in a memo, for example, that “no social media will be going out” — and none has from the department's main account since.

“A digital strategist will be coming on board” to manage the department's public communications, the memo said, and “incoming media requests will be carefully screened.”

A plan to scrub the agency's website of references to climate change was walked back after word leaked out, The Post reported. So was an early memo that sought to muzzle the U.S. Department of Agriculture's research arm, according to Reuters.

And the Interior Department's Twitter account was briefly, abruptly shut down after the National Park Service tweeted about the modest size of Trump's inaugural crowd.

The administration has said none of this is unusual, framing the clampdowns as routine housekeeping that any new government undertakes. And while the EPA's social media has gone quiet under Trump, a NASA account is still tweeting away about climate change.

Still, the White House has been open about targeting the EPA's wallet, if not its researchers' right to speak out.

The Trump administration has told the agency to freeze its grants and contracts, The Post reported — “a move that could affect everything from state-led climate research to localized efforts to improve air and water quality to environmental justice projects aimed at helping poor communities.”

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