The landslides in Wayanad happened because of 10 per cent more rainfall in a single day to which fossil fuels have contributed significantly by increasing the temperature.
A rapid attribution study by scientists from India, the UK, Sweden and the USA, under the aegis of the World Weather Attribution, has concluded that the already saturated soil in Wayanad and then the extremely heavy rainfall on June 30 precipitated the landslides.
The soil was saturated with rain water. Wayanad, as other studies, have illustrated, is the most susceptible district for landslides in Kerala.
On that single day (June 30), 140 mm of precipitation fell on saturated soils. This amount of precipitation is enough to fill a cricket stadium and translates into 23 lakh litres plus water.
A summary of the findings reads, ‘In today’s climate, which is 1.3 degree Celsius warmer than it would have been at the beginning of the industrial period, an event of this magnitude is expected to occur about once every 50 years. The event is the third heaviest single day rainfall event on record, with heavier spells in 2019 and in 1924, and surpasses the very heavy rainfall in 2018 that affected large regions of Kerala’.
Heavy one-day rainfall events have become about 17 per cent more intense in the last 45 years, over a period when the climate has warmed by 0.85 degree Celsius. Whether or not this is a long term trend remains undetermined because of lower quality weather data available from the pre-satellite era.
A large body of scientific data has now made it clear that there is extreme rainfall as the world gets warmer due to the burning of fossil fuels and other human induced changes. A warmer atmosphere can hold more moisture, leading to heavier downpours. Scientists globally agree that climate change, caused by burning oil, coal and gas and deforestation, is making rainfall heavier in many regions of the world.
The study further points out that other factors too such as loss of forest cover, land use changes, quarrying for building materials could all have contributed to the landslides although data pertaining to the same is not adequately available.
Arpita Mondal, Associate Professor at the Department of Civil Engineering, & Interdisciplinary Program in Climate Studies, Indian Institute of Technology Bombay said, “The findings reported here are physically consistent with those predicted by climate science. Millions of people are sweltering in deadly heat in the summer. Meanwhile, in monsoons, heavier downpours are fuelling floods and landslides, like we saw in Wayanad. These direct threats to people in India will continue to escalate as the climate warms and humans continue to regulate natural systems.”
