Climatologist Michael E. Mann is familiar with the uneasy relationship between politics and science.

The Penn State University professor and author of The Hockey Stick and the Climate Wars has worked under both the George W. Bush and the Barack Obama administrations in the U.S. He has also been the target of climate change skeptics for years, including those involved in the so-called climategate controversy, in which selected excerpts from stolen emails were used to try and discredit climate scientists and their work.

"Anytime that science and the findings of science have come into conflict with certain powerful vested interests, there's often been an effort by those who see themselves as potentially being at threat by the science to go after the scientists and the science and try to discredit the science," Mann told CBC's George Stroumboulopoulos Tonight.

On the show, Mann discussed his own experiences and also addressed the alleged muzzling of scientists by the federal government.

"My guess is that people of Canada didn't expect that they were voting for a government that would be censoring their scientists, that wouldn't be allowing scientists who are actually studying the impacts of climate change to be talking to the media," he said.

Mann likened the situation to the control the Bush administration exerted over its scientists' ability to communicate.

"It appears now that that culture, that ethos has now sort of spread across the border and it's what you're now seeing here in Canada."