Climate change to intensify water cycle in southern Western Ghats, study warns

Climate change is set to significantly accelerate the water cycle in the southern Western Ghats and adjoining coastal plains, a new study has warned.

It says that rising temperatures could trigger up to a 20% increase in annual rainfall and a 16% rise in extreme precipitation events for every 1◦C of warming, particularly during the Indian Summer Monsoon (ISM).

The findings of the study, conducted by a group of researchers led by Jobin Thomas, a postdoctoral research associate at Department of Geology and Geological Engineering at University of Mississippi, the U.S., have been published in the peer-reviewed Journal of Environmental Management.

Region-specific strategies

In the paper titled ‘Climate warming modifies hydrological responses in the southern Western Ghats and the western coastal plains (India): Insights from CMIP6-VIC simulations,’ the researchers stress the urgent need for region-specific adaptation strategies, including improved short-term water storage systems and integrated water management plans, to safeguard agriculture, hydropower generation and livelihoods in the region.

The researchers studied how the region’s climate and water patterns might change in the future using advanced climate models and hydrological simulations.

“All models robustly project an intensification of the hydrological cycle due to climate warming under two Shared Socioeconomic Pathways (SSPs)- SSP245 and SSP585- especially during the ISM season,” the study notes, adding that watershed areas would experience a markedly wetter ISM season and drier pre-monsoon season, leading to risks associated with concurrent floods, landslips and droughts.

Temperatures to increase

The study projects that by the end of the century, total annual rainfall in the region could rise by 250–400 mm under a moderate climate scenario (SSP245) and by 200–670 mm under a high-emissions scenario (SSP585). It also warns that both daytime and night time temperatures are expected to increase across seasons. “Maximum temperatures might rise by 1.7°C to 3.2°C, while minimum temperatures could go up by 1.9°C to 3.6°C,” according to study. This might potentially affect agricultural productivity.

“Global warming will intensify the hydrological cycle across the southern Western Ghats and adjoining western coastal plains, altering precipitation, temperature patterns and hydrological fluxes. The impacts of climate change necessitate investment in adaptation strategies to enhance regional resilience to hydroclimatic disasters,” the researchers say.

The work was conducted at the Institute for Climate Change Studies, Kottayam, under a project funded by the Department of Science and Technology.