Weather in the northern hemisphere "What was once extreme but rare is becoming increasingly frequent"
Extreme weather in the northern hemisphere is a consequence of man-made climate change, scientists agree. One researcher is sounding the alarm because heatwaves are no longer unusual.
Man-made climate change has increased the likelihood of high temperatures that have caused heatwaves in parts of the US, according to a study. The reason for this is the warming caused by the burning of coal, oil and natural gas, according to the World Weather Attribution research association.
In addition to the south-west of the USA, Mexico and Central America were also affected by the deadly heat in June. The high daily temperatures in the USA were 35 times more likely and 1.4 degrees hotter due to human-induced climate change, reported the World Weather Attribution group, which produces rapid climate studies.
So far, at least 125 people have died because of the current heatwave. "This is clearly related to climate change, the level of intensity we are experiencing, these risks," said the co-author of the study, Karina Izquierdo, based in Mexico City.
Climate scientist Friederike Otto from Imperial College London said that the alarming thing about the recent heatwave, which is still continuing on the North American continent, is that it is nothing out of the ordinary. Climate change has made night-time temperatures 1.6 degrees warmer. According to doctors, cooler night-time temperatures are important for surviving a heatwave.
"Very bad" effects
"From a sort of weather perspective, it was not uncommon in this context, but the effects were actually very bad," Otto told the AP news agency. "The changes we've seen over the past 20 years, which feels like it was just yesterday, are so severe."
According to their study, such a heatwave is now four times more likely than in 2000, when it is said to have been around 0.5 degrees Celsius cooler than now. Although other groups of scientists refer to global warming since the pre-industrial era in the mid-19th century, Otto considers a comparison of current events with the year 2000 to be more astonishing.
"What was once extreme but rare is becoming increasingly common," Carly Kenkel, who is responsible for marine studies at the University of Southern California, said of the World Weather Attribution study, in which she was not involved. The research group's analysis was "the logical conclusion based on the data".
Records fall again and again
The study looked at a large part of the continent, including southern California and the US states of Arizona, New Mexico, Texas and Oklahoma, as well as Mexico, Guatemala, El Salvador, Belize and Honduras. The hottest five consecutive days and the hottest five consecutive nights were analyzed.
For most of the area, the hottest days were recorded from June 3 to 7 and the hottest nights from June 5 to 9. According to Otto, however, the peak of the heat in some areas began on May 26.
In San Angelo, Texas, the record temperature of 43.8 degrees was measured on June 4. Between June 2 and 6, the temperature at Corpus Christi Airport never dropped below 26.7 degrees at night, according to the National Weather Service.
Heatwaves in Asia 45 times more likely
For the study, the researchers compared current temperatures with those of past heatwaves. Using a scientifically accepted method, they determined the extent to which global warming has affected the 2024 heatwave.
This involves comparing simulations of a fictitious world in which man-made climate change does not exist with the current reality.
The heatwave exacerbates "existing inequalities" between rich and poor, said co-author Izquierdo. Kenkel said that these inequalities are particularly noticeable at night because the availability of air conditioning depends on a person's financial situation.
Incidentally, similar studies have also been carried out with regard to heatwaves in Asia: They have become 45 times more likely as a result of man-made climate change, according to the World Weather Attribution study.
dpa
