Global heating and other human activity are making Asia’s floods more lethal

Families stranded on their rooftops. Homes buried by fast-flowing mud. Jagged brown craters scarring lush green hillsides.
The scenes are the result of a series of cyclones and storms in a heavy monsoon season that have struck Asia with torrential rains, gutting essential infrastructure and reshaping landscapes. The violent weather has killed at least 1,200 people in the past week and forced a million to flee without knowing whether their homes will still be standing when they go back.
The fallout marks a grim escalation in deadly weather across the region that has been aggravated by the blanket of carbon pollution heating the planet. A review by the Intergovernmental Panel on Climate Change (IPCC) projected that south and south-east Asia will suffer more intense rain as temperatures rise, with a “large increase” in flood frequency striking monsoon regions.
Roxy Koll, a climate scientist at the Indian Institute of Tropical Meteorology and coauthor of the latest IPCC report, said the cyclones’ behaviour had changed more than their number this season. “They are wetter and more destructive because the background climate has shifted,” he said. “Water, not wind, is now the main driver of disaster.”
Natural weather patterns including a La Niña cycle and a negative Indian Ocean dipole have helped to create conditions for the storms to form. Scientists have not determined the extent to which planet-heating pollution contributed to the death toll, which continues to rise with floodwaters, but they have long established that warmer air holds more moisture – about 7% per degree Celsius.
The extra water, together with the increase in energy from hotter oceans, leads to the formation of storms that pack far more punch.
“Across south and south-east Asia, storms this season have been carrying extraordinary amounts of moisture,” said Koll. “A warmer ocean and atmosphere are loading these systems with water, so even moderate cyclones now unleash rainfall that overwhelms rivers, destabilises slopes and triggers cascading disasters.
“Landslides and flash floods then strike the most vulnerable, the communities living along these fragile environments.”
The rains have loosened soils and levelled slopes in hilly regions that have wiped out villages and rendered roads and railways unusable. The floods have also hampered rescue efforts by disrupting electricity supplies and phone networks.
In Indonesia, where freshly cut logs have washed up in flooded parts of the country that also suffer from deforestation, the damage is thought to have been compounded by the felling of trees that could have soaked up water and stabilised the soil. The attorney general’s office is leading a task force to check if illegal activities contributed to the disaster, according to local media. Reuters also reported that the environment ministry planned to query logging, mining and palm plantation companies about their activities.
Sonia Seneviratne, a climate scientist at ETH Zurich and a co-author of the latest IPCC report, said other human factors may have amplified the extent of the floods, but that did not contradict the role of climate change in worsening rainfall.
“We have a very clear signal of increases in heavy precipitation with increasing warming, both on a global scale and in Asia,” she said. “The influence of human-induced climate change on the intensification of heavy precipitation is well established, and this is a key element in the reported floodings.”
The sliver of good news in the longer term is that the human cost of floods and storms has dropped sharply around the world as governments have set up early warning systems and got used to shepherding people out of danger before a disaster strikes. Even in middle-income countries that have made great progress in turning death tolls into displacement figures, however, experts say response systems are still patchy.
“The picture in south-east Asia shows that you still need even better early warning systems, even better shelter for people to go to in times of flooding … [and] even more nature-based solutions – the planting of trees and mangroves in those places particularly at risk of flooding to keep people safer,” said Alexander Matheou, the director of the Asia-Pacific region for the International Federation of Red Cross and Red Crescent Societies.
People also need “better social protection systems in disasters so they can immediately get cash and the food, medicine, and shelter they need when a disaster strikes”, he said.