Longer, warmer, more damaging heat waves since 1979: study

Climate change is making major heat waves longer around the world and affecting more people for longer with higher temperatures over larger areas, according to a new study.

Since 1979, heat waves around the world are 20 percent slower, meaning more people are hot for longer, and they occur 67 percent more frequently, according to a study published Friday in Science Advances. The study found that the highest temperatures of heat waves are higher than 40 years ago and that the area under a heat dome is larger.

Previous studies have shown that heat waves are getting worse, but this one is broader and focuses not only on temperature and area, but on the duration of heat waves and the way they travel through the air. continents, said climatologists and study co-authors Wei Zhang of Utah State University and Gabriel Lau of Princeton University.

From 1979 to 1983, global heat waves lasted eight days on average, but from 2016 to 2020, the figure increased to 12 days, the study revealed.

Eurasia has been the most affected area, with longer lasting heat waves, the study noted. Heat waves slowed mainly in Africa, while North America and Australia showed the largest increases in their global magnitude, which measures temperature and area, according to the study.

“This paper is a clear warning that climate change is making heat waves even more dangerous in a number of ways,” said Michael Wehner, a climatologist at Lawrence Berkeley National Laboratory, who was not involved in the research.

The researchers ran computer simulations that show this change is due to heat-trapping emissions from burning coal, oil and natural gas. The study found the footprint of climate change by simulating a world without greenhouse gas emissions, and concluded that it would not produce the worsening heat waves that have been observed in the last 45 years.

The study also analyzes changes in weather patterns that propagate heat waves. Atmospheric waves that move weather systems, such as the jet stream, weaken, so they don’t move heat waves as quickly, from west to east on most continents, but not all, Zhang said.

Several outside scientists praised the panoramic way Zhang and his colleagues examined heat waves, showing how they interact with weather patterns and global movement, and especially how they slow down.