Human-caused climate change made this summer's heat waves 2-10 times more likely: ECCC

File: A head of wheat is silhouetted by the sun in a wheat crop near Cremona, Alta., Tuesday, Sept. 6, 2022. (Jeff McIntosh, The Canadian Press)

Canadians have experienced numerous, sweltering heat waves this summer, and federal analysis reveals climate change made the unseasonable temperatures much more likely.

Climate scientists examined various periods of hot weather in June and July. During those months, Alberta saw temperatures soar above 30 C, nearly nine degrees above the seasonal average. Northwest Territories logged a peak temperature of 28.4 C, 9.2 degrees higher than usual. Nunavut recorded an unseasonal peak of 22.1 C, when temperatures on average hang below 15 C.

In those instances, and several others, "human influence on the climate made these events at least two to 10 times more likely to happen," reads a release from Environment and Climate Change Canada.

The scientists analyzed the heat waves through the Canadian government's new Rapid Extreme Weather Event Attribution system, which is still in its pilot phase. It compares the weather of today, which is influenced by current levels of atmospheric greenhouse gasses, to the weather and atmosphere of the 1800s, before the Industrial Revolution.

As the planet warms due to human emissions, heat waves grow more intense, wildfires intensify, drought periods extend, colder months become milder, glaciers thaw, and permafrost retreats.

Where we are now

Earth has logged several climate-related records this year. Perhaps most notably, climate scientists made headlines around the world when they announced July 21 was the hottest day ever recorded.

At the time, Carlo Buontempo, director of Europe's Copernicus Climate Change Service, issued a grim warning.

"We are now in uncharted territory," he said.

The organization made headlines again soon after when it revealed the record had been broken again the next day. Copernicus’ data showed the global average temperature -- ice caps and all -- was 17.15 C.

Scientists have long warned that the increasingly present fallout of climate change will force Canada to adapt to it, and that preparation is key for future generations. This year, experts said the unusually brutal forest fire season was a portrait of a new normal. Out-of-control blazes caused widespread destruction to people's homes, stripped forests of animal habitats and spewed more heat-trapping gas into the atmosphere.

The Earth's global temperature has risen 1.4 C since preindustrial times, global sea levels are up 10 centimetres since 1993, and our ice sheets are shedding 406 billion tons per year, according to NASA.

NASA calls those numbers “vital signs.” The 10 most recent years are the warmest on record. Through the widespread burning of fossil fuels, humans have increased the planet’s carbon dioxide content by 50 per cent in two centuries, far exceeding regular atmospheric ebbs and flows. The extent of summer arctic ice is shrinking by 12.2 per cent every 10 years.

Each fraction of a degree of warming brings with it a host of detrimental effects to Earth's climate.

Under the 2015 Paris Accord, countries including Canada agreed to limit warming to "well below" 2 C, with a goal of maintaining it at 1.5 C. That goal pertains to long-term averages over several years, meaning seasonal jumps above the average do not constitute a breach of the accord. However, the first 12-month period to exceed 1.5 C ran from February 2023 to January 2024.

"Exceeding 1.5 C could also trigger multiple climate tipping points," according to the journal Science, "such as breakdowns of major ocean circulation systems, abrupt thawing of boreal permafrost, and collapse of tropical coral reef systems — with abrupt, irreversible, and dangerous impacts for humanity."