Climate change intensified heat dome, firestorms in Pacific Northwest: study
The deadly heat dome that blanketed B.C. for nearly a month in 2021 was significantly worse because of human-caused climate change, according to a new study.
The study, published this week in Communications Earth and Environment, found the heat dome was 34 per cent larger and lasted 59 per cent longer, or 27 more days, than a heat wave would have without the effects of global heating caused by humans.
Analyzing 40 years of heat wave and wildfire data, Canadian and American researchers found that the greatest number of high temperature and low humidity records were broken in 2021, most of them in July.
The deadly heat wave stretched from June 18 to July 14 and caused temperatures to soar into the 40s in B.C., Washington and Oregon. Lytton hit a record 49.6 C on June 29, one day before a wildfire destroyed the village.
The B.C. Coroners Service confirmed 619 heat-related deaths during that time. Hospitals became dangerously hot and equipment failed.
While there's already a well-established link between heat waves and wildfires, this study shows how the heat dome was more intense because of human-caused climate change, said Piyush Jain, the study's lead author and a research scientist with Natural Resources Canada.
“Had the heat wave been not as intense or shorter, we probably wouldn't have seen a lot of those records like Lytton getting to 49.6 C,” he said Thursday.
Jain, who also co-wrote a study on last year's record-breaking wildfire season in Canada, said the same applies to extreme wildfires during and after the heat dome.
Across the Pacific Northwest, wildfires burned 32,000 square kilometres of forest in 2021, the study says. Of this, 21 per cent of that burnt land was because of wildfires that ignited during the heat dome. That number rises to 34 per cent within 10 days of the extreme heat wave.
“If we see further warming because of climate change, we may see more of these extreme events ... and they may be larger and more intense.”