Heat waves extend beyond summer due to climate change

Although summer is drawing to a close, we may have to continue to deal with periodic episodes of extreme heat. With the arrival of bad weather across much of the peninsula, yet another heat wave of the year has come to an end and the record temperatures recorded in recent days have dropped dramatically: on Saturday 12 September all 27 cities monitored by the Ministry of Health will be marked with the green dot. However, according to a study led by NASA's Goddard Institute for Space Studies (GISS) published in the journal Agu Advances, climate change is making peaks of anomalous heat increasingly frequent, even outside the season during which they usually occur.

Ask the Sun

In-depth questions generated by 24Ore AI

Questions are automatically suggested by 24Ore AI

based on the content displayed.

The study

The GISS researchers, led by Catherine Ivanovich, based the research on a detailed comparison between the extreme heat events recorded between 1980 and 1989 and those that occurred in the period 2015-2024. The results show how in the last 45 years heat waves have spread significantly over half of the emerged lands in terms of dry heat, and in just under half (48%) in terms of humid heat.

Loading...

This expansion, however, occurred asymmetrically: towards spring in some regions and towards autumn in others. Global warming, although not sufficient to explain this asymmetry on its own, represents its main cause. But, based on the data collected, it is likely that other factors such as changes in rainfall and land use also come into play.

The results

As the study shows, episodes of anomalous heat are expanding over time and are doing so unevenly across the world. In Western Europe, southern Africa and northwestern India, extreme temperatures are increasingly moving forward into spring, while in eastern Europe, the western United States, northern Africa and eastern China these events are becoming more frequent in the autumn months.

The research uses the city of Phoenix, the capital of Arizona, in the United States, as an example. Here, 183 days of extreme heat were recorded between 1980 and 1989 and 338 between 2015 and 2024. If, on the one hand, none of the events of the 1980s occurred after the end of the hot season, on the other, in the second decade of reference 6% occurred after this period. The researchers' analysis shows that the median date of dry heat extremes in the city has moved 10 days forward, while that of humid heat extremes has moved 5.5 days forward.