Published on
Updated
Reading 2 mins.
Climate change has made extreme heat waves, like those that affected Bangladesh, India, Laos and Thailand in April, at least 30 times more likely, according to an international scientific analysis published on Wednesday.
The study, carried out by twenty-two international climatologists from the World Weather Attribution (WWA) initiative, is based on the average of the maximum temperatures and the maximum heat index for four consecutive days in April in two regions, one covering southern and eastern India and Bangladesh, and the other including all of Thailand and Laos.
“Researchers found that climate change made such humid heat waves at least 30 times more likely, with temperatures at least 2°C higher than they would have been without climate change,” says WWA in a press release.
Extreme temperatures in Asia
On April 18, parts of India experienced temperatures above 44 C° which caused the death of at least 11 people near Bombay. It was the hottest day in six decades in Dhaka, capital of Bangladesh. On April 15, Thailand recorded its all-time heat record of 45.4C in the city of Tak, where two deaths were reported, as Sainyabuli province in Laos set a national record of 42.9C.
“Until global greenhouse gas emissions cease, global temperatures will continue to rise and such events will become more frequent and severe”warns WWA.
According to WWA, the recent humid heat wave, in Laos and Thailand, would have been virtually impossible without the influence of climate change, although it is still a very unusual event that only happens once every around 200 years. But with a rise of 2°C which will occur within thirty years if the emissions do not cease, such episodes are likely to occur every twenty years or so, underlines WWA.
Intense heat waves
In Bangladesh and India, such episodes, which used to occur less than once a century, are now expected once every five years on average. Without emission reductions, they will occur at least once every two years.
“Climate change is dramatically increasing the frequency and intensity of heat waves, one of the deadliest weather events around”said Friederike Otto, lecturer in climate science at the Grantham Institute for Climate Change, quoted in the press release.
Scientists have often shied away from attributing any particular phenomenon to climate change, but in recent years the field called “attribution science” exemplified by the WWA initiative has emerged.
Some weather phenomena have a more complex causal relationship with global warming, the WWA explains, than heat or cold spells, drought and extreme precipitation, which are easier to study.