Human-induced climate change behind Wayanad's deadly landslides: Study

A recent study conducted by the World Weather Attribution (WWA) has found that human-induced climate change intensified the rainfall that caused the devastating landslides in Wayanad, which resulted in over 200 fatalities.

WWA, an international team of climate experts, revealed that the heavy rainfall that occurred in the early hours of July 30 was 10% more intense due to climate change.

The rainfall, which reached 140 mm in just one day, is described as a “once in a 50-year event” for Wayanad, marking it as the third highest single-day rainfall on record for the area.

The study reveals that climate models predict a 10 % increase in the intensity of such extreme rainfall events due to current levels of global warming. Furthermore, under scenarios where global temperatures rise by 2 degrees Celsius above pre-industrial levels, these models forecast an additional 4 % increase in rainfall intensity for single-day events.

“Under a future warming scenario where the global temperature is two degree Celsius higher than pre-industrial levels, climate models predict even heavier 1-day rainfall events, with a further expected increase of about 4 per cent in rainfall intensity,” the study said.

This suggests that the frequency and severity of intense rainfall events will rise, consequently heightening the risk of landslides in the region.

“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, raising the need for adaptation actions that may include the reinforcement of susceptible slopes, landslide early warning systems, and construction of retaining structures to protect vulnerable localities,” it said.

WWA, known for evaluating the impact of climate change on extreme weather worldwide, has previously reported that recent heatwaves in India—one in April of last year and another in June this year—were also influenced by climate change.

The current study notes that intense one-day rainfall events have become more common in Kerala. Historically, such extreme rainfall was rare in the region, but with global temperatures having risen by approximately 1.3°C, these events are now expected to occur roughly once every 50 years.

Additionally, the study highlights that local factors, such as extensive quarrying for construction materials and a 62 % reduction in forest cover in Wayanad from 1950 to 2018, have exacerbated the area's vulnerability to landslides during heavy rainfall. The loss of forest cover and the effects of quarrying have likely increased the susceptibility of the slopes, making them more prone to landslides when faced with intense rainfall.

The study also found that factors such as quarrying for building materials, and a 62% reduction in forest cover in Wayanad between 1950 and 2018, may have contributed to increased susceptibility of the slopes to landslides during heavy rainfall.

“More stringent assessments of landslides, restricting construction in hillside areas and minimising deforestation and quarrying are needed to avoid similar disasters in the future,” it said.

By taking these precautionary measures, it is hoped that the region can better mitigate the impact of future extreme weather events and prevent similar disasters.