Human factor one part of the ‘recipe’ for recent western heatwave: climatologist

The late-June heatwave that blanketed much of Western Canada in searing temperatures was intense and persistent, with 700 temperature records being set, including 55 records in Manitoba alone.

Environment and Climate Change Canada’s (ECCC) senior climatologist David Phillips said among several factors, it is possible that human activity did play a role. He described the weather as being similar to a recipe with several different ingredients or factors coming together.

“So this heatwave was caused by nature, but there was also a human component. It did come from tailpipes and smokestacks, but was it 20 per cent, 30 per cent? We can’t separate out the sun’s energy, and ocean temperatures, but also with human beings. We had a factor to play in this,” Phillips told CTV Morning Live.

Phillips said this heatwave, the likes of which he has never seen in his 50 years as a climatologist, was unusual for a variety of reasons.

He said the height of the weather “bubble” made a difference as it stretched up as high as a jet aircraft flies. That trapped a lot of hot air in a large area over the western part of the country. All that heat energy that might ordinarily cause evaporation did not do so this time because of generally low soil moisture and little precipitation. Therefore, the heat went entirely toward warming the air. Even the calendar played a role in keeping temperatures up.

“This is typically not the dog days of summer that usually come a month later. The long hours of daylight in June helped keep things heated up as well. There were only a few hours to cool down (at night) before they went back up again,” said Phillips.

Phillips said records fell across Manitoba, from Churchill in the far north to Pilot Mound. Winnipeg saw six days in a row with high temperatures above 30 C.

He said climate change may not be a direct cause of isolated weather events like the heatwave, but the impact of it is still a significant concern.

“It does make weather events more impactful, scarier, more extreme, more intense, more out of season, out of place.”