India’s river basins drying up from climate change
- Most of India’s 24 river basins found extremely vulnerable to droughts
- Sixty-six per cent of croplands vulnerable, affecting food security for 1.36 billion people
- India must take urgent policy measures in response to the situation, says FAO
A predominantly farming country of 1.36 billion people, India leads countries affected by climate change with agricultural incomes set to be heavily affected by decreasing rainfall and increasing temperatures, says a World Economic Forum document.
According to the study, published this month (May) in Global and Planetary Change, vast areas served by 16 of 24 river basins face lowered soil moisture levels, posing sustainability risks to croplands with implications for the country’s food security. The findings indicate that 66 per cent (more than one million square kilometres) of the country’s croplands are vulnerable.
“Majority of the 24 river basins are extremely vulnerable to vegetation droughts because of shifting/declining rainfall patterns and surging average annual temperatures”
Manish Kumar Goyal, Indian Institute of Technology
“Analysing climate data [from] the 1982-to-2010 period, the research team concluded that the majority of the 24 river basins are extremely vulnerable to vegetation droughts (defined as negative impact on vegetation growth due to prolonged deficit in water availability) because of shifting/declining rainfall patterns and surging average annual temperatures, and are incapable of recovering from fallouts,” Manish Kumar Goyal, associate professor at the Indian Institute of Technology, Indore, and one of the authors of the study, tells SciDev.Net.
The researchers studied 10 different types of vegetation cover in the 24 river basins, including croplands and forest lands, for resilience. Among major basins marked as increasingly vulnerable to vegetation droughts were the Indus, Ganges, Brahmaputra, Cauvery, Godavari, Krishna, Mahanadi, Pennar, Mahi, Tapi, Sabarmati and Narmada.
At least a third of the areas around 18 river basins is non-resilient to vegetation droughts and over 50 per cent of each vegetation type is vulnerable, says the study, pointing to the fragility of the country's terrestrial ecosystems.
The study is based on climate data of mean monthly temperatures obtained from the Indian Meteorological Department, precipitation data from the 1901-to-2010 period and soil moisture data from 1982 to 2010, available with the Earth System Research Laboratory of National Oceanic Atmospheric Administration. Vegetation productivity data was extracted from the Global Inventory Modelling and Mapping Studies.
Croplands are the most dominant land cover in the country. The analysis shows that such land cover will be a major victim of future vegetation droughts, Goyal warns.
“Rice-producing regions in the eastern coastal plains and areas in the Ganges and Indus river basins are particularly vulnerable to vegetation droughts,” says Goyal. “Soil moisture deficit amid declining rain during the winter cropping season can endanger major wheat-producing river basins such as the Indus, western Ganges and Sabarmati and Mahi.” UN-FAO India’s assistant representative Konda Reddy Chavva says the findings are unprecedented and should facilitate the understanding of policymakers regarding vegetation drought hotspots and prompt them to roll out viable strategies. “Policy measures should focus on timely drought prediction, monitoring, impact assessment and response,” Chavva tells SciDev.Net.
India, Chavva says, needs to invest in drought-warning technologies and drought-resilient crop varieties. Water retention structures, good tillage practices, flood irrigation, crop rotation, mulching, better water and crop management, enhanced groundwater recharge and rainwater harvesting are among measures he suggests that farmers adopt.
Elevated public awareness among drought-vulnerable communities, effective planning of watershed and local water storing and use, reduction in water demand and conservation can help cope with vegetation droughts and their impacts, Chavva says.
This piece was produced by SciDev.Net’s Asia & Pacific desk.