Ocean temperatures warmed by human-caused climate change fed the intense rainfall that triggered deadly floods and landslides across Asia in recent weeks, according to an analysis released on Wednesday (December 10, 2025).
The rapid study by World Weather Attribution focused on heavy rainfall from cyclones Senyar and Ditwah in Malaysia, Thailand, Indonesia and Sri Lanka starting late last month. The analysis found that warmer sea surface temperatures over the North Indian Ocean added energy to the cyclones.
Floods and landslides triggered by the storms have killed more than 1,600 people, with hundreds more still missing. The cyclones are the latest in a series of deadly weather disasters affecting Southeast Asia this year, resulting in loss of life and property damage.
“It rains a lot here but never like this. Usually, rain stops around September but this year it has been really bad. Every region of Sri Lanka has been affected, and our region has been the worst impacted,” said Shanmugavadivu Arunachalam, a 59-year-old schoolteacher in the mountain town of Hatton in Sri Lanka’s Central Province.
News in Frames | An island ravaged by a cyclone
After the fall: Uprooted trees line the damaged buildings in Gampola town following the landslide.
A drenched prince: Muddy floodwaters partially submerge a Buddha statue in Kelaniya following Cyclone Ditwah.
Grit through grief: In Kandy, people sift through the wreckage for survivors and possessions after landslides.
Desolate outlook: Amid the debris of a landslide in Gampola, Kandy, a woman holding a child observes the damage to a temple.
Precious cargo: People carrying pets and other possessions make their way through a flooded street in Wellampitiya following heavy rain.
Rescue mission: Evacuation under way in Kotmale, Nuwara Eliya, for Indian passengers with the help of Sri Lankan authorities. Photo: Indian Air Force-X via ANI
Picking up pieces: People salvage belongings from a flooded house after flash floods in Wellampitiya on the outskirts of Colombo.
For a spot of sun: Flood-hit residents collect their belongings from railway tracks in Kandy after drying them.
On the edge: A damaged house perches dangerously at a landslide site in Warathenna, Kandy.
Heartwarming gesture: Helping hands assist an elderly man across a flooded street in Wellampitiya.
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Warmer sea surface temperatures
Sea surface temperatures over the North Indian Ocean were 0.2° Celsius higher than the average over the past three decades, according to the WWA researchers.
Without global warming, the sea surface temperatures would have been about 1° Celsius colder than they were, according to the analysis. The warmer ocean temperatures provided heat and moisture to the storms.
When measuring overall temperatures, the world is currently 1.3° Celsius warmer than global average during pre-industrial times in the 19th century, according to the National Oceanic and Atmospheric Administration.
“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,” said Mariam Zachariah, with the Centre for Environmental Policy at Imperial College London and one of the report’s authors.
Using tested methods to measure climate impacts quickly
The WWA is a collection of researchers who use peer-reviewed methods to conduct rapid studies examining how extreme weather events are linked to climate change.
“Anytime we decide to do a study, we know what is the procedure that we have to follow,” said Zachariah, who added that they review the findings in house and send some of their analysis for peer review, even after an early version is made public.
The speed at which the WWA releases their analysis helps inform the general public about the impacts of climate change, according to Zachariah.
“We want people everywhere to know about why something happened in their neighbourhood,” Zachariah said. “But also be aware about the reasons behind some of the events unfurling across the world.”
The WWA often estimates how much worse climate change made a disaster using specific probabilities. In this case, though, the researchers said they could not estimate the precise contribution of climate change to the storms and ensuing heavy rains because of limitations in climate models for the affected islands.
Climate change boosts Asia’s unusually heavy rainfall
Global warming is a “powerful amplifier” to the deadly floods, typhoons and landslides that have ravaged Asia this year, said Jemilah Mahmood, with the Sunway Centre for Planetary Health, a Malaysia-based think tank that was not involved with the WWA analysis.
“The region and the world have been on this path because, for decades, economic development was prioritised over climate stability,” Mahmood said. “It’s created an accumulated planetary debt, and this has resulted in the crisis we face.”
The analysis found that across the affected countries, rapid urbanisation, high population density and infrastructure in low lying flood plains have elevated exposure to flood events.
“The human toll from cyclones Ditwah and Senyar is staggering,” said Maja Vahlberg, a technical adviser with the Red Cross Red Crescent Climate Centre. “Unfortunately, it is the most vulnerable people who experience the worst impacts and have the longest road to recovery.”
Published – December 11, 2025 08:13 am IST
