Imma Perfetto
Cosmos science journalist
New research has identified several regions of the globe where heatwaves are increasing at a rate far higher than state-of-the-art climate models have been projecting.
These regions include eastern Australia, central China, Japan, Korea, the Arabian Peninsula, parts of South America, the Arctic, and, most intensely, northwestern Europe.
“In most areas, the hottest days of the year are warming about as fast as typical summertime days, which is the dominant signal of climate change,” says PhD candidate Samuel Bartusek of Columbia University in the US, who co-authored the paper in the journal PNAS.
“In the hotspots that we point out, however, the hottest days have been warming particularly fast, which could be for various reasons.
“In some places there could be more occurrences of specific heatwave-inducing weather patterns, or soil drying could be amplifying the hottest temperatures – and it will be important to untangle these specific local drivers.”
Extreme heat events, or heatwaves, can have significant impacts on societal and natural systems. These events have increased in intensity, frequency and duration with climate change.
Unprecedented or record-shattering heat extremes, which are rare under current climatic conditions, are expected to become more frequent.
Recent examples include the record-breaking heat in Europe, central Russia, and Southeast Asia in 2023.
Accurately simulating the response of these “extreme-extremes” to warming, the authors stress, is important for adapting to potential climate futures.
“Due to their unprecedented nature, these heat waves are usually linked to very severe health impacts, and can be disastrous for agriculture, vegetation, and infrastructure,” says lead author Kai Kornhuber, of the International Institute for Applied Systems Analysis’ (IIASA) Energy, Climate, and Environment Program.
“We’re not built for them, and we might not be able to adapt fast enough.”
The study looked at heat waves over the past 65 years to assess how trends in temperature increases stack up to projections by climate models.
The findings also identify regions where increases in temperatures are lower than models 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.
The results highlight the need to better understand and model the drivers of extreme heat. However, the authors stress that the best way to reduce both uncertainty in and exposure to climate impacts is a rapid transition away from fossil fuels to stabilise global temperature rise.
