Human-caused climate change warmed ocean temperatures, intensifying heavy rainfall from cyclones Senyar and Ditwah in Malaysia, Thailand, Indonesia, and Sri Lanka, leading to floods and landslides that killed over 1,600 people. A World Weather Attribution study found North Indian Ocean sea surface temperatures were 0.2°C higher than the three-decade average. The world is now 1.3°C warmer than pre-industrial levels.
A rapid analysis by the World Weather Attribution (WWA) links human-induced climate change to the intense rainfall from cyclones Senyar and Ditwah, which struck Malaysia, Thailand, Indonesia, and Sri Lanka starting late last month. These storms triggered floods and landslides that have killed more than 1,600 people, with hundreds still missing. Researchers determined that without global warming, North Indian Ocean sea surface temperatures would have been about 1°C cooler.
Warmer air holds more moisture, leading to heavier rain, as explained by Mariam Zachariah from Imperial College London's Centre for Environmental Policy. "When the atmosphere warms, it can hold more moisture. As a result, it rains more in a warmer atmosphere as compared to a world without climate change," she said.
In Sri Lanka's Hatton, 59-year-old schoolteacher Shanmugavadivu Arunachalam described the unusual downpours: "It rains a lot here but never like this. Usually, rain stops around September but this year it has been really bad."
WWA could not quantify climate change's exact role due to limitations in models for the island regions. Jemilah Mahmood of Malaysia's Sunway Centre for Planetary Health called global warming a "powerful amplifier" for Asia's deadly floods, typhoons, and landslides this year, blaming decades of prioritizing economic growth over climate stability.
Red Cross Red Crescent Climate Centre adviser Maja Vahlberg noted, "The human toll from cyclones Ditwah and Senyar is staggering. Unfortunately, it is the most vulnerable people who experience the worst impacts."
Rapid urbanization, high population density, and infrastructure in low-lying floodplains have heightened exposure across the affected nations. WWA comprises scientists using peer-reviewed methods for quick studies on how climate change influences extreme weather.
