Two months ago, France experienced the hottest May on record, with record highs in some cities. Last month, France reignited with a spring heat wave that also affected Spain, Italy and other countries. And this month, Poland and other parts of Eastern Europe were hit by the heat.
Now, temperatures across Europe are skyrocketing again, extending eastward by three digits or close from Spain to the British Isles. Wildfires hit by heat are burning in many countries, and many of the continents are suffering from long droughts.
And there are still two months left in the summer.
Scientists say the extreme heat that has already lasted this year is in line with the trend. According to them, heat waves in Europe are increasing in frequency and intensity at a faster rate than most other parts of the globe, including the western United States.
Global warming plays a role, as is the case with heat waves around the world, as it is on average about 2 degrees Celsius (1.1 degrees Celsius) higher than in the late 19th century before trapping carbon dioxide and other heat. .. Gas has spread. Therefore, extreme heat will take off from a higher starting point.
But beyond that, there are other factors that may make Europe a heat wave hotspot, some of which include atmospheric and ocean circulation.
The two heat waves cannot be exactly the same. The current scorching temperatures that reached England and Wales on Monday were partially caused by a region of upper cyclones that had been stagnant for days off the coast of Portugal. In atmospheric scientist terminology, it is known as “cut off flow.” This is because it was cut off from the westerly rivers that orbit the planet at high altitudes and the jet streams at mid-latitudes.
Low pressure zones tend to draw air towards them. In this case, the low pressure zone is steadily drawing air from North Africa to Europe. Kai Kornhober, a researcher at the Lamont-Doherty Earth Observatory, part of Columbia University, said:
Dr. Kornhuber Research published this month It found that European heat waves have increased in frequency and intensity over the last 40 years, at least in part linking changes in jet streams. Researchers have found that many European heat waves occur when the jet stream is temporarily split into two, leaving a region of weak wind and high pressure air between the two branches, causing extreme heat buildup. I found that I would do it.
Efi Rousi, senior scientist at the Potsdam Institute for Climate Research in Germany and lead author of the study, said the current heat wave seems to be associated with such a “double jet”. The last two weeks. This can lead to the creation of cut-off flows, and can also lead to areas of weak winds in Europe that allow the heat to persist, Dr. Rus said.
“This seems to really support this accumulation of heat waves,” she said.
There may be other reasons why Europe is seeing more and more persistent heat waves, but some of these are currently the subject of debate among scientists. Dr. Rus said that natural climate change can make it difficult to elicit certain impacts.
Dr. Cornhuber said Arctic warming, which is happening much faster than in other parts of the world, could play a role. As the Arctic warms at a faster rate, the temperature difference between the Arctic and the equator decreases. This leads to a reduction in summer winds, which has the effect of prolonging the life of the meteorological system. “We see an increase in sustainability,” he said.
There are also signs that changes in the Atlantic North-South thermal salt circulation, one of the world’s major currents, can affect the climate of Europe. Last year, Dr. Rousi published a paper using computer simulations showing that as the world warms, the atmospheric circulation changes as the current weakens and the European summer dries.
Like the rest of the world, heat waves in Europe can increase the likelihood of others occurring in the same region, as periods of extreme heat dry the soil.
When the soil is moist, some of the sun’s energy is used to evaporate the water, providing a slight cooling effect. However, once one heat wave wipes out almost all soil moisture, there is little room for evaporation when the next hot air wave arrives. Therefore, much of the sun’s energy burns the surface and increases heat.