Climate change and unplanned development triggering landslides, say experts

Mumbai: Following the devastating landslides in the Wayanad district of Kerala, experts claimed that climate change and unplanned development, are to blame for the catastrophic landslides other than the meteorological factors.

Geographically, Kerala is bounded by Arabian Sea to its west and the Western Ghats to its east. This makes it highly susceptible for heavy rains during the season. Orography has a strong effect on rainfall distribution in the mountainous region of Kerala. The rainfall potential of the region increases from the coastal belt towards the Western Ghats, reaching a maximum on the windward side of the Ghats and rapidly decreases on the leeward side. The rainfall characteristics over Kerala are unique because of the influence of isolated steep-sloped structures separated by the wide Palghat gap.

“Climate change is drastically changing rainfall patterns in Wayanad. What was once a cool, humid environment with year-round drizzles and monsoon rains, is turning into one marked by drier, hotter summers and intense downpours during the monsoons. This change has increased the risk of landslides. Dry soils absorb less water and heavy rainfalls cause run-offs that can lead to landslides, such as the ones we've seen this week,” said Mariam Zachariah, Research Associate, Imperial College London.

Citing similar views, Mahesh Palawat, Vice President- Meteorology and Climate Change, Skymet Weather said: “Monsoon patterns have definitely changed and they now behave in an erratic manner. Earlier during the Monsoon season, we used to witness uniform rains and no convective activity, but now we see rains which are more of pre-Monsoon characteristics that include thundershowers. Kerala has not been witnessing typical Monsoon rains and has been struggling to achieve its average rainfall. Despite these heavy showers, it is yet to surpass its average rainfall so far."

"Also, with the rise in air as well as ocean temperatures, there has been a drastic increase in the moisture. The Arabian Sea has been warming at a faster rate, pumping moisture in the atmosphere, making it unstable. All these factors are directly linked to global warming,” he added.

Roxy Mathew Koll, Climate Scientist, Indian Institute of Tropical Meteorology (IITM), Pune called for early warning systems to curtail the damage from the natural disasters: “Roughly half of Kerala are hills and mountainous regions where the slope is more than 20 degrees and hence these places are prone to landslides when heavy rains occur. Landslide prone areas are mapped and available for Kerala. Panchayats with hazardous areas should be identified and sensitised. We need to monitor rainfall data in these hotspots and prepare early warning systems targeted at hazard prone areas. This is possible with the current technology and know-how and could in fact save lives and livelihoods.”

According to him, other than climate change, we also need to evaluate the land use changes and development activities happening over landslide prone areas. "Often landslides and flash floods occur over regions where the impact of both climate change and direct human intervention in terms of land use changes are evident. At the same time, there have been many severe landslides over regions with minimal land use changes also,” said Koll.

“Strengthening infrastructure by investing in climate-resilient bridges and roads will help withstand extreme weather events and facilitate quicker rescue operations. Promoting sustainable land management is also crucial; practices such as reforestation, controlled deforestation, and sustainable agriculture can maintain hillside stability and reduce soil erosion, thereby lessening the effects of heavy rains,” said Prof Anjal Prakash, Clinical Associate Professor (Research) and Research Director, Bharti Institute of Public Policy, Indian School of Business and IPPC Author.