Canada says summer heat waves linked to climate change

Canada's environment ministry said Friday that climate change had made nearly all the heat waves recorded this summer more likely, including in an Arctic area where temperatures hit 35 degrees Celcius.

Earlier this year, Environment and Climate Change Canada debuted a new tool that examines the connection between human-caused climate change and extreme weather, by comparing current data with pre-industrial data.

The tool's first-ever application found that human activity had made a mid-June east coast heave wave two to 10 times more likely.

In its latest analysis, the ministry looked at the 37 hottest heat waves recorded this summer across the country.

Four of those 37 were made at least 10 times more likely by human activity. For 28 of the heat waves, the figures were two to 10 times more likely.

"Throughout the summer, we saw above normal temperatures shift across different regions of Canada," environment ministry researcher Nathan Gillet said.

"Over the past 77 years, summer temperatures have warmed by 1.7 degrees Celsius, nationally, on average, and the principal cause of this warming is human-induced climate change," he told reporters.

One area of the Arctic, the Qikiqtaaluk region of Nunavut, experienced a heat wave that lasted 25 days over September and October.

Further west, in the Arctic town of Inuvik in the Northwest Territories, temperatures hit 35 degrees this summer.

"This is really exceptional in that region," Gillet said.

The ministry said Canada is warming at roughly double the global average rate, and the rate of warming in the Arctic is three times higher than the global average.

"These 'once in 100 years' climate-related weather events are becoming more frequent, severe, and costly," the ministry said.

This winter, the environment ministry expects to use its new tool to assess the correlation between human-caused climate change and extreme cold snaps.