The year 2023 marked the hottest on record, standing at 2.12 degrees Fahrenheit above the 20th-century average, surpassing the previous record set in 2016. With the past decade witnessing the top 10 warmest yearly averages, and 2024 poised to possibly set a new record, the world is undeniably warming. However, amidst this general temperature rise, an alarming trend has emerged: specific regions experiencing extraordinarily intense and repeated heat waves that far exceed any climate change model predictions.
A recent study unveils the first global map of these areas, found on every continent except Antarctica. These regions, akin to inflamed skin spots on the earth’s surface, have been the sites of deadly heatwaves that have claimed tens of thousands of lives, destroyed crops and forests, and triggered devastating wildfires in recent years.
The study’s authors express concern over these unexpected and dramatic deviations from previous records, questioning the efficacy of climate models in accurately predicting regional climate risks. Kai Kornhuber, the lead author and an adjunct scientist at the Columbia Climate School’s Lamont-Doherty Earth Observatory, describes these regions as “temporary hothouses,” resulting from physical interactions that are not yet fully understood.
The study, recently published in the Proceedings of the National Academy of Sciences, examines heat waves over the past 65 years. It identifies areas where extreme heat is escalating much more rapidly than moderate temperatures, leading to new, often staggering, high-temperature records. One such instance was the nine-day heatwave that struck the U.S. Pacific Northwest and southwestern Canada in June 2021, where temperatures in some areas soared up to 30 degrees Celsius or 54 degrees Fahrenheit above previous records.
These exceptional heat waves have predominantly occurred in the past five years, impacting regions like central China, Japan, Korea, the Arabian peninsula, eastern Australia, and parts of Africa. Other affected areas include Canada’s Northwest Territories and High Arctic islands, northern Greenland, southern South America, and patches of Siberia.
Northwestern Europe stands out as the region with the most intense and consistent heat wave activity, contributing to some 60,000 deaths in 2022 and 47,000 deaths in 2023 across Germany, France, the UK, the Netherlands, and other countries. Here, the hottest days of the year are warming twice as fast as the average summer temperatures.
The researchers term these statistical trends as “tail-widening,” referring to the unexpected occurrence of temperatures at the far upper end or beyond anything that would be expected with simple upward shifts in mean summer temperatures. However, this phenomenon is not universal. In contrast, many other regions are experiencing maximum temperatures lower than what models would predict.
While rising overall temperatures contribute to increased likelihood of heatwaves, the precise reasons for these extreme heat outbreaks are unclear. Several hypotheses attribute these to changes in the jet stream, long-term climate change, and other factors.
Despite being relatively better prepared, heatwaves in the United States still cause more deaths than all other weather-related causes combined. This has led to recent calls for heatwaves to be named like hurricanes, to increase public awareness and government preparedness.
Kornhuber warns that these unprecedented heatwaves can have severe health impacts and disastrous consequences for agriculture and infrastructure, adding, “We’re not built for them, and we might not be able to adapt fast enough.”
The study also involved contributions from Richard Seager and Mingfang Ting of Lamont-Doherty Earth Observatory, and H.J. Schellnhuber of the International Institute for Applied Systems Analysis.
