Amid the continued upward march in average temperatures over the past decades, a recent surge of record shattering extreme heat waves raise questions about the degree to which climate models can provide adequate estimates of relations between global mean temperature changes and regional climate risks. The study looks at heat waves over the past 65 years, identifying areas where extreme heat is accelerating considerably faster than typical warm-season temperatures overall. This often results in maximum temperature records that have been repeatedly broken. These extreme heat waves have been hitting predominantly in the last five years, although some occurred in the early 2000s or before. The most hard-hit regions include central China, Japan, Korea, the Arabian Peninsula, eastern Australia and parts of South America and the Arctic. The most intense and consistent signal, however, comes from northwestern Europe, where sequences of heat waves contributed to around 60,000 deaths in 2022 and 47,000 in 2023. These occurred across Germany, France, the United Kingdom, and the Netherlands among others.

In September this year, new maximum temperature records were set in Austria, France, Hungary, Slovenia, Norway and Sweden. Many parts of the United States Southwest and California also saw record temperatures well into October. In these regions, extreme temperatures are increasing faster than average summer temperatures, at a rate far higher than what state-of-the art climate models have been projecting for the past few decades. The phenomenon is however not happening everywhere; the study shows that the increase in temperatures across many other regions is lower than what models would predict. These include wide areas of the north-central United States and south-central Canada, interior parts of South America, much of Siberia, northern Africa and northern Australia. This study is an important first step towards addressing the emerging risk from extreme and unprecedented heat by identifying regions that have historically faced rapidly increasing risk and quantifying the ability of models to reproduce these signals.

Links:
Mapping the world’s climate danger zones

Lokale ‘hitte-hotspots’ slaan wetenschappers met verstomming