Europe is facing increasingly severe heatwaves, raising fresh questions among scientists about how far human adaptation can go in a rapidly warming climate. Late June brought record temperatures across France, Spain, the United Kingdom, Belgium, the Netherlands, Switzerland, and Germany, with Germany’s national weather service reporting an unprecedented stretch of intense early-summer heat.
At the same time, large parts of the central and eastern United States are also under heat warnings, with temperatures expected to exceed 37.8C to 46.1C, adding to global concerns about escalating heat extremes. Medical experts warn that prolonged periods above 30C, especially when nighttime temperatures remain above 20C, place significant stress on the human body.
Physician and environmental medicine expert Claudia Traidl-Hoffmann notes that the body does have mechanisms to cope with heat, particularly in populations regularly exposed to high temperatures. “The human body can adapt, and those adaptations are more developed in people who are continuously exposed to heat,” she said. However, she stresses that meaningful adaptation is a very slow process, measured not in years but in centuries.
The human body begins activating cooling systems at around 23C. Blood vessels widen to release heat, and sweating increases to regulate core temperature. These processes are usually effective, but when overwhelmed, they can lead to severe consequences, including cardiovascular collapse and multi-organ failure. Traidl-Hoffmann explained that when core temperature rises too far, the body can lose control of essential functions. “At around 42 degrees Celsius, the body experiences severe cell damage, multiple organ failure and, without immediate treatment, death can occur,” she said.
