The summer of 2026 has seen Europe once again face record-breaking heat. The extreme temperatures have been more than simply a “hot summer.” Beginning in late May, strong high-pressure systems stayed over parts of Europe, trapping hot air and creating what is often called a “heat dome.” Hot and dry air from North Africa also moved northward, pushing temperatures even higher.

A heat dome forms when a strong high-pressure system remains over one area and prevents hot air from escaping. Under high pressure, air sinks and becomes warmer as it is compressed. Clouds are less likely to form, so strong sunlight continues to heat the ground. As the soil dries, less water is available to evaporate and cool the air, causing temperatures to rise further.

The early heat wave in May intensified in June. According to the Copernicus Climate Change Service, the average temperature in western Europe in June 2026 was 3.06°C above the 1991–2020 average, making it the hottest June ever recorded in the region.

Temperatures across much of western Europe were far above normal. In France, another heat wave lasted for 16 days in July. Rather than being defined by a single exceptional event, the summer brought repeated, continuous heat waves over several months.

The impact went far beyond heat-related discomfort. The high temperatures and low rainfall dried out soil and vegetation, increasing wildfire risks in countries such as Spain and France. Low river levels also caused problems for transportation and water management. In France, unusually warm river water created difficulties for nuclear power plants that depend on rivers for cooling, and some plants were expected to reduce electricity production.

Extreme heat also created serious health risks. In Spain, around 2,100 deaths in August 2026 were estimated to be related to heat. Older adults, outdoor workers, and people without adequate cooling are especially vulnerable. With many European buildings designed primarily for cold winters, measures to adapt them to extreme summer heat are becoming increasingly urgent.

Urban areas can increase the danger through the urban heat island effect. Concrete and asphalt absorb heat during the day and release it slowly at night, while areas with fewer trees have less shade and natural cooling. As a result, cities may stay hot even after sunset. When temperatures remain high at night, the body has less time to recover from daytime heat stress.

Responding to heat waves therefore requires more than air conditioning. Cities need more trees, shaded spaces, cooler materials, and public cooling areas. Buildings can also use better insulation, external shading, and natural ventilation. Heavy use of air conditioning can also put more pressure on energy systems. Climate change does not directly create heat domes. High-pressure systems and similar weather patterns also existed in the past. What has changed is the background temperature of the atmosphere. World Weather Attribution found that if similar weather conditions had occurred in 1976, daytime temperatures would have been around 3.5°C lower.

Climate change therefore makes the same weather patterns much hotter and more dangerous than before. The summer of 2026 shows that extreme heat is no longer only a problem for southern Europe. High temperatures began early and spread across western and central Europe as well as the United Kingdom. Wildfires, water shortages, energy problems, and health risks are now interconnected parts of the same crisis. Europe can no longer treat each heat wave as a temporary emergency. As extreme heat becomes the new reality, cities, buildings, and public systems will need to adapt to a much hotter future.

Reporter

Sieun Jeon

cherryjeon06@seoultech.ac.kr

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