Scientists Find Fingerprints of Climate Change on Wayanad Landslides

New Delhi: dely landslides in Kerala's ecologically fragile Wayan district were triggered by a heavy burst of rainfall, me 10 per cent heavier by climate change, according to a new rapid attribution study by a global team of scientists.

team of 24 researchers from India, Sweden, US and UK said that more than 140 mm of rainfall fell in a single day on soils highly saturated by two months of monsoon precipitation, triggering catastrophic landslides and floods that killed at least 231 people in Wayan.

" rainfall that triggered landslides occurred in a region of Wayan that has highest landslide risk in state. Even heavier downpours are expected as climate warms, which underscores urgency to prepare for similar landslides in norrn Kerala," Maja Vahlberg, a climate risk consultant at Red Cross Red Crescent Climate Centre, said.

To measure impact of human-caused climate change, scientists from World Wear Attribution (WWA) group analysed climate models with high enough resolution to accurately reflect rainfall in relatively small study area.

models indicated that intensity of rainfall has increased by 10 per cent due to climate change, y said.

models also predict a furr four per cent increase in rainfall intensity if average global temperature rises by two degrees Celsius compared to 1850-1900 average.

scientists, however, said re is a "high level of uncertainty" in model results as study area is small and mountainous with complex rainfall-climate dynamics.

Having said that, increase in heavy one-day rainfall events aligns with a growing body of scientific evidence on extreme rainfall in a warming world, including in India, and understanding that a warmer atmosphere holds more moisture, leing to heavier downpours.

According to scientists, atmosphere's capacity to hold moisture increases by about 7 per cent for every one-degree Celsius rise in global temperature.

earth's global surface temperature has alrey increased by around 1.3 degrees Celsius due to rapidly rising concentration of greenhouse gases, primarily Carbon Dioxide and Methane. Scientists say this is reason behind worsening extreme wear events, such as droughts, heatwaves and floods worldwide.

WWA scientists said that while relationship between land cover, land use changes and landslide risk in Wayan is not fully clear from existing studies, factors, such as quarrying for building materials and a 62 per cent reduction in forest cover may have increased slopes' susceptibility to landslides during heavy rainfall.

Or researchers have also linked Wayan landslides to a combination of forest cover loss, mining in fragile terrain and prolonged rain followed by heavy precipitation.

S Abhilash, director of vanced Centre for Atmospheric Rar Research at Cochin University of Science and Technology (CUSAT), h earlier told PTI that warming of Arabian Sea is leing to formation of deep cloud systems, resulting in extremely heavy rainfall in Kerala in a short period and increasing risk of landslides.

"Our research found that souast Arabian Sea is becoming warmer, causing atmosphere above Kerala to become rmodynamically unstable. This instability is allowing formation of deep clouds," he h said.

According to landslide atlas released by ISRO's National Remote Sensing Centre last year, 10 out of top 30 landslide-prone districts in India are in Kerala, with Wayan ranked at 13th spot.

A study published by Springer in 2021 said all landslide hotspots in Kerala are in Western Ghats region and are concentrated in Idukki, Ernakulam, Kottayam, Wayan, Kozhikode and Malappuram districts.

It said about 59 per cent of total landslides in Kerala have occurred in plantation areas.

A 2022 study on depleting forest cover in Wayan showed that 62 per cent of forests in district disappeared between 1950 and 2018, while plantation cover rose by around 1,800 per cent.