2023-07-14 04:21:20
Summer has only just begun in the northern hemisphere, but already intense heat waves are hitting many parts of the world hard, from Europe to China to the United States, where record temperatures are expected. this weekend — illustration of extreme conditions amplified by global warming.
More than 100 million Americans are under heat alerts, according to the government website heat.gov. Texas, Arizona, Nevada and California are expecting potentially hazardous conditions in the coming days, with all-time high temperatures possible, US weather services have warned.
At the same time, Italy, Spain, France, Germany and Poland are also facing a large heat wave. The mercury is expected to rise to 48°C on the islands of Sicily and Sardinia, “potentially the hottest temperatures ever recorded in Europe”, according to the European space agency.
North Africa is also affected. In Morocco, which has been experiencing a series of heat waves since the beginning of the summer, a red heat alert has been issued for several provinces.
Some regions of China, including the capital Beijing, are also suffering from a strong heat wave. One of the country’s main electricity companies said on Monday it recorded a record daily electricity generation, due to increased demand linked to high temperatures.
Globally, the month of June was the hottest ever measured, according to the European Copernicus and American NASA and NOAA agencies. Then, the first full week of July was in turn the hottest on record, according to preliminary data from the World Meteorological Organization (WMO).
Heat is one of the deadliest weather events, the WMO said. Last summer, in Europe alone, high temperatures caused more than 60,000 deaths, according to a recent study.
But this extreme weather, which occurs more frequently because of climate change, “unfortunately becomes the new normal”, asserted Thursday in a press release the secretary general of the WMO, Petteri Taalas.
The cyclical El Nino weather phenomenon, which usually causes global temperatures to rise, is also contributing to the worsening situation.
Fires, floods, heat
In the United States, the summer has already been marked by a series of weather disasters. Smoke from the fires in Canada, where more than 500 fires are still out of control, led to several episodes of heavy air pollution across the northeastern United States in June.
Catastrophic floods have affected the state of Vermont (northeast) this week. Scientists reminded that global warming can also contribute to more frequent and heavier rains, by increasing water vapor in the atmosphere.
Finally, for weeks, the south of the country has been facing a heat wave that has left residents no respite.
Mercury in California’s Death Valley desert this weekend might equal or even exceed the highest air temperature ever reliably measured on Earth, according to climatologist Daniel Swain of the University of California to Los Angeles.
Officially, the absolute world record has been set at 56.7°C by the WMO. But it was recorded in Death Valley in 1913 and many meteorologists do not consider it reliable, explained the scientist, who prefers to stick to the 54.4°C recorded at the same place in 2020 and 2021.
Marine heatwaves too
The oceans are not spared from the heat either.
In southern Florida (southeastern United States), the temperature of the water near the coast exceeds 32°C, according to the American Agency for Oceanic and Atmospheric Observation (NOAA).
Surface temperatures in the Mediterranean will be “extremely high in the coming days and weeks”, sometimes over 30°C, with values over 4°C above average in large areas of the west of this sea, according to the WMO.
Marine heat waves have devastating effects on the species that live there, their survival and their migrations, as well as consequences for fishing.
At the other end of the globe, the Antarctic sea ice has reached its lowest extent for the month of June.
Compared to the pre-industrial era, the world is already experiencing warming close to 1.2°C as a result of human activity, mainly the use of fossil fuels (coal, oil, gas).
For WMO chief Petteri Taalas, the current heat waves underline “the growing urgency to reduce greenhouse gas emissions as quickly and as much as possible”.
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