Europe is experiencing its second extreme heat wave in just one month, with many temperature records continuing to be broken. World Health Organization (WHO) Director General Tedros Adhanom Ghebreyesus on June 28 warned that Europe is currently the fastest growing continent in the world, with temperatures doubling the global average.
This trend has actually lasted for decades. According to the European Union (EU) Copernicus Climate Change Agency, the average temperature in Europe has increased by about 0.56°C every decade since the mid-1990s. The average temperature in Europe is currently about 2.4°C higher than in the pre-industrial period (1850-1900), while the global average increase is about 1.4°C.
Scientists believe that the underlying cause of global warming is still greenhouse gas emissions from human activity, but many local factors make excess heat concentrated in Europe more than in other regions.
One of the most important reasons is the geographical location of Europe, which is associated with the Arctic, a region that is also heating up faster than most other regions. Warming up the climate causes the Arctic sea ice to melt, revealing the dark ocean surface.
Unlike snow, which has the ability to reflect most of the Sun's radiation back into space, the water surface absorbs more heat, creating a feedback loop that continues to increase temperatures. This process, called the albedo effect, also occurs on land as winter snow cover in Europe shrinks. According to Copernicus, last year, the snow cover in Europe at its peak was still about 1/3 lower than the multi-year average.
Scientists also noted changes in atmospheric circulation. Usually, strong wind bands in the upper atmosphere will bring cool air from the Atlantic to the mainland. However, when the temperature difference between the equatorial and Arctic regions decreases due to melting ice and snow, these wind bands tend to change direction or split into two branches, creating a high pressure area that is almost standing still, causing hot air to be "locked down" for many consecutive days.
Research published in 2022 showed that almost the entire increase in frequency and intensity of heat waves in Western Europe recently is related to the state of "double winds" that last longer than normal. The historic heat wave of 2003, which involved about 70,000 deaths in Europe, also occurred when the double winds lasted for 29 days. The heat wave in May was formed by the "thermal arch", and the current one is related to the "Omega block", pulling hot air from the Sahara desert to the mainland.
Another less noted factor is that Europe's air quality improvement policy also inadvertently causes heat waves to occur more frequently. Since the 1980s, European countries have tightened industrial emission controls, helping to significantly reduce the amount of aerosol in the atmosphere. These are extremely small dust particles that can harm human respiration, but have the ability to reflect part of the Sun's radiation. Reducing aerosol brings great benefits to public health, but the unexpected price is the weakening of the natural cooling effect in the atmosphere, causing more sun radiation to be retained closer to the ground.
