How has climate change shifted the odds of extreme cold? A new tool seeks the answer

Federal environment officials will be able to quickly analyze how climate change is shifting the odds of extreme cold temperatures starting this winter, officials said Friday, broadening the application of a system rolled out over the summer to study heat waves.

The results will show the extent to which human-caused climate change affected the likelihood of a given cold wave.

While cold extremes may conjure images of frostbite and hypothermia, they also have benefits, such as killing off invasive pests. Infestations of mountain pine beetle, which has ravaged large swaths of Western Canada's forests, have been linked to warmer winters.

"There are some aspects of cold extremes where, you know, having fewer is a bad thing," said Nathan Gillett, a climate scientist with Environment and Climate Change Canada.

"From a scientific perspective, it's natural to extend our analysis in this way from the hot extremes."

This summer, the department began to pilot a system that rapidly analyzes how climate change has influenced the likelihood of a heat wave. The system works by comparing models of the current climate and a pre-industrial climate to see how much more likely a given extreme has become.

Climate scientists have said this allows them to translate for the general public how decades of human activity, mostly the burning of vast amounts of fossil fuels, is already contributing to dramatic shifts in weather extremes — generally, there is more extreme heat, and less extreme cold.

The results from what's called a rapid attribution study not only underline the importance of fighting climate change, officials say, but can help communities better prepare and adapt to its risks.

During a briefing Friday, officials said this summer was the warmest on record in Quebec and Atlantic Canada, and the fourth hottest in Canada, according to records dating back to 1948.

In that time, Canada's summer temperatures have warmed by 1.7 degrees, a trend driven largely by human-caused climate change, Gillett said.

In season-ending results shared Friday, Gillett said all 37 major heat events the department looked this summer were found to be more likely to have happened because of climate change, with most falling between two and 10 times more likely.

At least three heat waves in the rapidly warming far north were more than 10 times more likely due to climate change.

"It's certainly very concerning. The ecosystems and communities are not adapted to those kinds of temperatures," Gillett said.

Inuvik, the Northwest Territories town south of the Arctic Ocean, experienced one of the more exceptional heat waves of the summer when temperatures soared in early August to nearly 27 degrees, 13 degrees above normal daily highs.

Officials say they expect to expand the attribution system next year to cover extreme precipitation, too.

This report by The Canadian Press was first published Oct. 25, 2024.