Climate change made heatwaves 45 times more likely in South Asia

BATHINDA: Extreme temperatures above 40°C that impacted billions of people across Asia in April are more likely caused by human-caused climate change, states the rapid attribution analysis by an international team of leading climate scientists from the World Weather Attribution group, released on Wednesday. The study highlights how heatwaves intensified by climate change are making life much tougher for people living in poverty across Asia and the 1.7 million displaced Palestinians in Gaza.
Asia was hit by severe heatwaves this April. In South and Southeast Asia, Myanmar, Laos, Vietnam broke records for their hottest April day, and the Philippines experienced its hottest night ever. In India, temperatures reached as high as 46ºC. The heat was also extreme in West Asia, with Palestine and Israel experiencing temperatures above 40°C. The month was the hottest April on record globally and the eleventh consecutive month in a row a hottest month record was broken.
Heat-related deaths were widely reported, with at least 28 in Bangladesh, five in India and three in Gaza during April, while surges in heat deaths have also been reported in Thailand and the Philippines this year. These are only preliminary figures and because heat-related deaths are notoriously underreported, it is likely there were hundreds or possibly thousands of other heat-related deaths in Asia during April. The heat also led to crop failure, loss of livestock, water shortages, mass die-off of fish, widespread school closures, and the heat has been linked to low voter turn-out in Kerala, India.
Climate change, caused by burning oil, coal and gas, and other human activities like deforestation, is making heatwaves more frequent, longer and hotter around the world. To quantify the effect of human-caused warming on the extreme temperatures across Asia, scientists analysed weather data and climate models using peer-reviewed methods to compare how these types of events have changed between today’s climate, with approximately 1.2°C of global warming, and the cooler pre-industrial climate.
The scientists also analysed the possible influence of the El Niño–Southern Oscillation, a naturally occurring climate phenomenon that shifts between El Niño, neutral and La Niña conditions.
The study also analysed historical weather data for a region of South Asia that includes India, Bangladesh, Myanmar, Laos, Vietnam, Thailand and Cambodia. The researchers did not carry out a full attribution analysis for this region as the World Weather Attribution has conducted similar studies in 2022 and 2023, and the data from weather observations showed that the attribution results would not be significantly different.
In West Asia, the scientists found that April heatwaves with temperatures above 40°C are more frequent due to warming caused by human activities. In today’s climate, with 1.2°C of warming, similar heatwaves are expected to occur about once every 10 years. Climate change made the heat about five times more likely and 1.7°C hotter. In the future, extreme temperatures in West Asia could become even more frequent and intense. If warming reaches 2°C, as they are expected to in the 2040s or 2050s unless emissions are rapidly halted, similar heatwaves will occur about once every five years and will become another 1°C hotter. El Niño does not have an influence on the high temperatures in West Asia.
Without human-induced climate change, such an event would have been virtually impossible, even under El Niño conditions, the scientists found. Overall, climate change made this year’s heatwave 1°C hotter, while El Niño made the heatwave a further 0.2°C hotter. If global warming reaches 2°C, similar heatwaves in the Philippines will occur every two to three years and will become another 0.7°C hotter.
In South Asia, similar 30-day heatwaves can be expected to occur about once every 30 years. However, they have already become about 45 times more likely and 0.85°C hotter due to climate change, according to historical weather data. This result is consistent with World Weather Attribution’s previous studies in the region that found climate change made April heatwaves about 1°C hotter and 10-30 times more likely. The analysis of historical weather data also found that similar heatwaves are twice as likely to occur during El Niño conditions.
The study highlights how climate change is making life much tougher for people in Asia living in poverty and dealing with the effects of war. In Gaza, many of the 1.7 million displaced people are living in improvised tents that trap heat, have limited access to healthcare and clean drinking water, and lack options to stay cool. Across South and Southeast Asia, the hundreds of millions of people who live in informal housing and work outdoors, like farmers, construction workers and street vendors are disproportionately affected by extreme heat.
While high temperatures are the norm across Asia during April, the increasing risk of dangerous heat, particularly in rapidly growing cities, such as Manila, highlights the critical need for heat planning that protects vulnerable groups, the researchers say. Countries across Asia such as India have made substantial progress on developing heat action plans. However, across the continent, there are still significant gaps in planning for dangerous heat.
The study was conducted by 13 researchers as part of the World Weather Attribution group, including scientists from universities and meteorological agencies in Malaysia, Sweden, the Netherlands, and the United Kingdom.
Mariam Zachariah, Researcher at the Grantham Institute - Climate Change and the Environment, Imperial College London, said: “Climate change is bringing more days with potentially deadly temperatures to Asia every year. “This result is unsurprising, but important for highlighting the dangers of extreme heat in Asia. “Unless the world takes massive, unprecedented steps to reduce emissions and keep warming to 1.5°C, extreme heat will lead to even greater suffering in Asia.”
Friederike Otto, Senior Lecturer in Climate Science at Grantham Institute - Climate Change and the Environment, Imperial College London, said: “From Gaza to Delhi to Manila, people suffered and died when April temperatures soared in Asia. “Heatwaves have always happened. But the additional heat, driven by emissions from oil, gas and coal, is resulting in death for many people. “If humans continue to burn fossil fuels, the climate will continue to warm, and vulnerable people will continue to die.”