They travel around 8 km less per day, compared to ten years ago. Heat waves have an increasing tendency to linger over the same region, which exacerbates their dangerousness, according to a new study published Friday.
Researchers analyzed heat waves globally, over a period from 1979 to 2020, using models based in particular on observations from weather radars and satellites.
8 to 12 days
While previous research has focused on the frequency and intensity of heat waves, few have so far looked at their propagation in both space and time. But heat waves, like storms or other weather phenomena, move, told AFP Wei Zhang, one of the co-authors of the study, published in the journal Science Advances.
They also observed that the average duration of heatwaves increased from around 8 days in the early 1980s to 12 days at the end of the period studied. Their study also showed that heat waves were traveling further than before, and confirmed the increase in the frequency of such events. “Heat waves traveling farther and moving slower will have more devastating consequences for nature and society in the future if greenhouse gases continue to increase,” the study concludes.
Anthropogenic factor
The researchers then examined the role of climate change in these changes. To do this, they used climate models to simulate two scenarios — with and without greenhouse gas emissions — and compared them with the actual behavior of heat waves. “It’s pretty clear to us that the dominant factor here in explaining this trend is anthropogenic,” meaning “greenhouse gases” from human activities, said Wei Zhang of Utah State University. .
He said he was particularly worried about the cities where these heat waves occur, which may lack greenery or cooler places for disadvantaged populations, for example not being equipped with air conditioning.