Extreme heat has engulfed parts of Western Europe, with wildfires raging in France and Spain, a worsening drought in Portugal, and the third hottest day on record in the UK recently.
France experienced its hottest May on record, with record highs in some cities.
In June, France was blistered again, by a spring heat wave that also affected Spain, Italy and other countries.
Then, in July, Poland and other parts of Eastern Europe suffered during a spell of extreme heat.
Now temperatures across Europe are soaring yet again from Spain to the British Isles and spreading east.
Why Europe is becoming a heatwave hotspot?
Global warming plays a role, as it does in heat waves around the world, because temperatures are on average about 2 degrees Fahrenheit (1.1 degrees Celsius) higher than they were in the late 19th century, before emissions of carbon dioxide and other heat-trapping gases became widespread. So extreme heat takes off from a higher starting point.
Wildfires stoked by the heat are burning in many countries, and much of the continent is in the throes of a lengthy drought.
Other factors, some involving the circulation of the atmosphere and the ocean, that may make Europe a heat wave hot spot:
The current scorching temperatures that reached into England and Wales recently were caused in part by a region of upper level low-pressure air that has been stalled off the coast of Portugal for days.
It’s known as a “cutoff low” in the parlance of atmospheric scientists, because it was cut off from a river of westerly winds, the mid-latitude jet stream, which circles the planet at high altitudes.
Low-pressure zones tend to draw air toward them.
In this case, the low-pressure zone has been steadily drawing air from North Africa toward it and into Europe.
It’s pumping hot air northward.
Heat waves in Europe had increased in frequency and intensity over the past four decades, and linked the increase at least in part to changes in the jet stream.
The researchers found that many European heat waves occurred when the jet stream had temporarily split in two, leaving an area of weak winds and high pressure air between the two branches that are conducive to the build-up of extreme heat.
There are also indications that changes in one of the world’s major ocean currents, the Atlantic Meridional Overturning Circulation, may affect Europe’s climate.