An international team comprising leading climate scientists, which studied the extremely humid heat in South and Southeast Asia in April 2023, said that heat waves in India and Bangladesh which used to occur less than once a century on average can now be expected around once in five years.
According to rapid attribution analysis by the team as part of the World Weather Attribution group, in Bangladesh and India, events like the recent humid heat wave used to occur less than once a century on average; they can now be expected around once in five years and if temperature rise reaches 2°C — as will happen within around 30 years if emissions are not cut rapidly — events like this will occur, on average, at least once every two years.
For the last two weeks of April 2023, many parts of Bangladesh, India, Thailand and Lao PDR experienced record-high temperatures.
The study was conducted by 22 researchers as part of the World Weather Attribution initiative, including scientists from universities and meteorological agencies in India, Thailand, Australia, Denmark, France, Germany, Kenya, the Netherlands, the UK, and the United States.
The study states that human-caused climate change made April’s record-breaking humid heatwave in Bangladesh, India, Laos and Thailand at least 30 times more likely.
Longer and hotter
Across the world, climate change has made heat waves more common, longer and hotter.
To quantify the effect of climate change on the Asian heatwave, scientists analysed weather data and computer model simulations to compare the climate as it is today, after about 1.2°C of global warming since the late 1800s, with the climate of the past, following peer-reviewed methods.
Who is vulnerable
Chandra Sekhar Bahinipati of the Indian Institute of Technology Tirupati and one of the scientists involved in the study said, “Although we have recognized heatwaves as one of the deadliest disasters, particularly in countries like India, Bangladesh, and Thailand, there is a lack of knowledge with respect to who is vulnerable, loss and damage estimation, household coping mechanisms, and the most effective heat action plans.”
He added that except for the human casualties, other economic and non-economic loss and damage indicators are not documented.