The landslides that killed hundreds of people in Kerala’s Wayanad were triggered by a burst of rainfall that was made about 10 per cent heavier by human-caused climate change, a study has found.The study by World Weather Attribution (WWA), an international group of researchers, found that the excessive rainfall in the early hours of July 30 that triggered the landslides was a “once in a-50-year event”.
The study highlights the need for rigorous assessments of landslide risk and improved early warning in hillside regions of northern Kerala to prevent repeat landslide disasters.
The study was conducted by 24 researchers as part of the World Weather Attribution group, including scientists from universities and meteorological agencies in India, Malaysia, the United States, Sweden, the Netherlands, and the United Kingdom.
The findings are in line with a large scientific body of evidence on extreme rainfall around the world, the scientists say – a warmer atmosphere, heated by fossil fuel emissions, can hold more moisture, resulting in heavier downpours.
The study highlights a range of factors that turned the landslide into a disaster.
The soils in the hilly Wayanad district are among the loosest and most erodible in Kerala, with high risk of landslides during the monsoon season. More stringent assessments of landslides, restricting construction in hillside areas and minimising deforestation and quarrying are needed to avoid similar disasters in the future, the researchers say.
The rainfall was well forecast and some villages were evacuated. However, the extreme number of casualties indicates that warnings failed to reach many people and did not specifically outline what impacts could be expected in particular regions, the researchers say.