It noted the landslides occurred in a mountainous region with loose, erodible soils after 140 mm of precipitation fell on saturated soils.
Published Aug 14, 2024 | 11:34 AM ⚊ Updated Aug 14, 2024 | 11:34 AM
An image from the landslide site in Wayanad.
A new study by the World Weather Attribution (WWA) linked the devastating landslides in Wayanad district on 30 July and floods that killed at least 231 people to climate change.
The study was done by a team of 24 researchers from India, Sweden, the US and the UK.
The international organisation, which specialises in analysing the role of climate change in extreme weather events, found that in Wayanad factors such as quarrying for building materials, and a 62 percent reduction in forest cover, may have contributed to the increased susceptibility of the slopes to landslides when the heavy rain fell.
The landslides were preceded by a staggering 140 mm of rainfall in a single day.
According to WWA, a rainfall event of this magnitude is expected to occur about once every 50 years and the event is the third heaviest 1-day rainfall event on record, with heavier spells in 2019 and 1924, and surpasses the very heavy rainfall in 2018 that affected large regions of Kerala.
It also noted that the Wayanad landslides, which resulted in devastating loss of lives, occurred in a mountainous region with loose, erodible soils after 140 mm of precipitation fell on saturated soils.
The study also highlighted the role of human factors in exacerbating the disaster.
Deforestation, with a 62 percent reduction in forest cover, and quarrying activities weakened the slopes, making them more susceptible to landslides.
“The rainfall that triggered the landslides occurred in a region of Wayanad that has the highest landslide risk in the state. Even heavier downpours are expected as the climate warms, which underscores the urgency to prepare for similar landslides in northern Kerala,” Maja Vahlberg, a climate risk consultant at the Red Cross Red Crescent Climate Centre, said.
While the Indian Meteorological Department (IMD) issued warnings about heavy rainfall, the lack of granular data made it difficult to pinpoint areas at high risk of landslides, hindering effective evacuation efforts.
The WWA’s findings underscore the urgent need for adaptation measures to mitigate the increasing risk of landslides.
These include reinforcing vulnerable slopes, developing advanced landslide early warning systems, and constructing protective structures in high-risk areas.
The study serves as a stark reminder of the growing threat posed by climate change and the imperative to take decisive action to protect lives and livelihoods.
The WWA stated that the increase in climate change-driven rainfall found in this study is likely to increase the potential number of landslides that could be triggered in the future.
It then highlighted, “Overall, the available climate models indicate a 10% increase in intensity. Under a future warming scenario where the global temperature is 2°C higher than pre-industrial levels, climate models predict even heavier 1-day rainfall events, with a further expected increase of about 4% in rainfall intensity.”
An excerpt from the study further added, “The increase in heavy one-day rainfall events is in line with a large and growing body of scientific evidence on extreme rainfall in a warming world, including in India, and the physical understanding that a warmer atmosphere can hold more moisture, leading to heavier downpours.”
S Abhilash, the director of the Advanced Centre for Atmospheric Radar Research at Cochin University of Science and Technology (CUSAT), had earlier told PTI that the warming of the Arabian Sea is leading to the formation of deep cloud systems, resulting in extremely heavy rainfall in Kerala in a short period and 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,” he had said.
According to the landslide atlas released by ISRO’s National Remote Sensing Centre last year, 10 out of the top 30 landslide-prone districts in India are in Kerala, with Wayanad ranked at the 13th spot.
(Edited by Muhammed Fazil with PTI inputs)
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