A new study reveals that the deadly landslides in Kerala’s ecologically fragile Wayanad district were triggered by intense rainfall, made 10 percent heavier by climate change. Conducted by a global team of scientists from India, Sweden, the US, and the UK, the study warns that such events are likely to become more frequent as the climate continues to warm.
The research, conducted by the World Weather Attribution (WWA) group, utilized climate models with high resolution to accurately assess rainfall in Wayanad. The results indicate that the intensity of rainfall has already increased by 10 percent due to human-caused climate change. The models also predict a further increase of 4 percent in rainfall intensity if the average global temperature rises by two degrees Celsius above the 1850-1900 average.
Despite the study’s findings, researchers caution that there is a “high level of uncertainty” due to the small, mountainous study area and the complex dynamics of rainfall and climate in Wayanad. However, the increase in extreme one-day rainfall events aligns with a broader body of scientific evidence showing a link between global warming and more intense rainfall, including in India. As the atmosphere warms, its capacity to hold moisture increases by about 7 percent for every one-degree Celsius rise in global temperature, leading to heavier downpours.
The Earth’s global surface temperature has already risen by approximately 1.3 degrees Celsius, primarily due to the increased concentration of greenhouse gases such as carbon dioxide and methane. This temperature rise is contributing to worsening extreme weather events, including droughts, heatwaves, and floods worldwide.
The study also highlights the complex relationship between land cover changes and landslide risk in Wayanad. Although the exact impact of land use changes is not fully understood, factors such as quarrying for building materials and a 62 percent reduction in forest cover are believed to have increased the slopes’ susceptibility to landslides during heavy rainfall. Other research has linked the Wayanad landslides to a combination of forest cover loss, mining in fragile terrain, and prolonged periods of rain followed by heavy downpours.
Abhilash, Director of the Advanced Centre for Atmospheric Radar Research at Cochin University of Science and Technology (CUSAT), pointed out that the warming of the Arabian Sea is leading to the formation of deep cloud systems, which result in extremely heavy rainfall in Kerala in a short period, thereby increasing the risk of landslides. “Our research found that the southeast Arabian Sea is becoming warmer, causing the atmosphere above Kerala to become thermodynamically unstable. This instability is allowing the formation of deep clouds,” Abhilash explained.
Kerala is particularly vulnerable to landslides, with 10 out of the top 30 landslide-prone districts in India located in the state, according to a landslide atlas released by ISRO’s National Remote Sensing Centre. Wayanad ranks 13th on this list, and studies have shown that nearly 59 percent of landslides in Kerala occur in plantation areas. A 2022 study on the depletion of forest cover in Wayanad found that 62 percent of the district’s forests disappeared between 1950 and 2018, while plantation cover increased by around 1,800 percent.
The findings underscore the urgent need for climate action and better land management practices to mitigate the increasing risks of extreme weather events in vulnerable regions like Wayanad.