Explainer: What's fueling Europe's heat wave?

A powerful heat wave is gripping large parts of Europe, with temperatures soaring well above seasonal averages. The World Meteorological Organization (WMO) on Thursday attributed the event to a heat dome effect originating from the African continent. A high-pressure system over the region has trapped warm air close to the surface, compressing it and causing temperatures to spike.

"The lack of cloud cover allows intense solar radiation to directly reach the ground," the WMO noted in its bulletin, "further intensifying already elevated surface temperatures." This kind of weather pattern, often referred to as a "heat dome," can persist for several days or even weeks, leading to long-lasting and widespread heat waves.

Meteorologists warn that this event is not isolated, but part of a growing trend of extreme weather across the continent. Compounding the situation is a severe lack of rainfall earlier in the year. According to a June 23 report from the European Commission's Joint Research Centre (JRC), much of Europe experienced significantly reduced rainfall between March and May, leading to widespread drought. The parched land retains less moisture and amplifies surface heating, worsening the effects of high temperatures.

"The current drought is threatening Europe's ecosystems and agricultural systems," the JRC report said, warning of cascading impacts on food production, water availability and biodiversity.

Urban centers are feeling the brunt of the heat wave due to the urban heat island effect. Dense concentrations of concrete, asphalt and buildings absorb heat during the day and release it slowly at night, keeping city temperatures higher than surrounding rural areas. This not only increases energy demands for cooling but also heightens health risks for vulnerable populations.

Scientific evidence points to climate change as a major underlying factor. A study published by World Weather Attribution (WWA) on June 20 found that human-caused global warming has significantly increased the likelihood of unusually hot summer days in the United Kingdom. The report concludes that what was once considered rare is becoming the new normal.

"These kinds of summer temperatures would have been extremely unlikely without the influence of human activity," the WWA report states, adding that heat waves now pose a growing public health threat across Europe.

With the combination of natural weather patterns, environmental degradation and climate change, experts stress the urgency of both mitigation and adaptation. This includes reducing greenhouse gas emissions, rethinking urban planning, investing in water conservation, and improving early warning systems.

As temperatures continue to rise and weather extremes become more frequent, the current European heat wave serves as a stark reminder of the accelerating climate crisis and its widespread impact.