Climate scientists calculate role human-caused climate change plays in shifting weather extremes Français

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Environment and Climate Change Canada

Jul 17, 2025, 15:27 ET

From: Environment and Climate Change Canada

GATINEAU, QC, July 17, 2025 /CNW/ - Environment and Climate Change Canada is committed to climate research into how and why the country's climate has changed over the decades. Research like this will help us predict future changes and provide Canadians with a deeper understanding of how human-caused climate change affects extreme weather events, like heat waves and cold snaps.

This summer, climate scientists are using the Rapid Extreme Weather Event Attribution system to analyze heat waves across Canada to determine how CO2 and other emissions from human activities impacted extreme heat. During the summer of 2024, climate scientists analyzed the 37 most extreme heat events across Canada. In all cases, they found that the heat waves were likely because of climate change.

This summer, human-caused climate change already made two heat waves in Canada much more likely to occur. This means that human influence on the climate made the following events at least two to 10 times more likely to occur:

Yukon (June 20 to 23)

Peak daily high temperature during the heat wave: 22.0 °C
Degrees above normal daily high temperature: 6.5 °C

Alberta (May 28 to 31)

Peak daily high temperature during the heat wave: 28.8 °C
Degrees above normal daily high temperature: 11.3 °C

Analysis of how weather events are linked to human-caused climate change relies on advanced climate models and observations to compare today's climate with what existed in the pre-industrial era (1850 to 1900). Comparison allows climate scientists to answer the question, "What role did human-caused climate change play in this event?" and provides concrete results that can be quickly understood.

This past winter, climate scientists also piloted a new function to analyze climate change's impact on cold weather events. As the global climate continues to warm, extreme cold temperatures are becoming less frequent. This work provides Canadians with direct insight into how human-caused climate change and its devastating impacts are affecting their lives and weather today and see these changes as they unfold.

Canadians are encouraged to regularly monitor weather forecasts, take all weather alerts seriously, and get prepared for weather-related events by developing an emergency plan and being ready to adjust their travel plans.

Canadians can download the WeatherCAN app to receive weather alert notifications directly on their mobile devices. Alerts help Canadians prepare to face severe weather events, save lives, and reduce the impacts on property and livelihoods.

Quotes

"With this important work, our scientists are proving that the changing climate plays a significant role in severe weather. Rising global temperatures are creating longer dry seasons and hotter conditions, which in turn increase the risk of wildfires. This knowledge helps us so we can work together to protect our environment, our communities, and our future."
– The Honourable Julie Dabrusin, Minister of Environment and Climate Change

"During this demanding and challenging wildfire season, it's clear that more extreme natural disasters and severe weather events are becoming increasingly common. Before the mid-1990s, Canada had seen just three disasters that caused over $500 million in damages—now, we're seeing disasters of that scale almost every year. As events like wildfires, heat waves, and smoke become more frequent, it's important to understand the risks to yourself, your family, and your community. Visit Get Prepared for practical steps you can take to stay safe. The well-being of Canadians will always be our top priority."
– The Honourable Eleanor Olszewski, Minister of Emergency Management and Community Resilience and Minister responsible for Prairies Economic Development Canada

Quick facts

In January, climate scientists analyzed a two-day cold snap in western Ontario. The coldest temperature recorded during the extreme cold event was -34.0 °C.
Extreme climate-related weather events are becoming more frequent, severe, and costly. 2020, 2021, 2022, and 2023 rank in the top 10 years based on insurance claims, surpassed only by the 2016 Fort McMurray fires, the 2013 flooding in Calgary and Toronto, and the 1998 Quebec ice storm (source).
Environment and Climate Change Canada is the country's official source for weather information and severe weather warnings and is committed to providing Canadians with accurate and timely weather information, including severe weather alerts.
The latest forecasts and severe weather warnings are available through Environment and Climate Change Canada's weather website and the WeatherCAN app (available for Android and iOS devices).

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