A new study has determined that the melting of glaciers due to global warming might trigger food shortages in India and China.
According to a report in New Scientist, the irrigation water vital for the grain crops that feed India and China is at risk of drying up, as global warming melts the glaciers that feed Asia's biggest rivers.
Rains feed the Ganges, Yellow and Yangtze Rivers in India and China during the monsoon season, but during the dry season, they depend heavily on meltwater from glaciers in the Himalayas. The Gangotri Glacier in the Himalayas alone supplies 70% of the flow of the Ganges in the dry season.
The dry season is precisely when water is needed most to irrigate the rice and wheat crops on which hundreds of millions of people depend for their staple calories.
"Severely diminished meltwater could make the flow of the three great rivers seasonal," warned Lester Brown of the Earth Policy Institute.
The Intergovernmental Panel on Climate Change reported last year that many Himalayan glaciers could disappear by 2035. According to Brown, Chinese glaciologists now estimate that two-thirds of the glaciers on the Tibet-Qinghai Plateau could be gone by 2060.
The warning echoes another issued earlier this month by a former agriculture minister of Pakistan, Amir Mohammad, who warned that 60% of Pakistan's people depend on grain irrigated by the Indus River, which is also dependent on meltwater from Himalayan glaciers.
"Melting of glaciers has already started affecting the water flow into Indus river system," he told local newspapers.
Meanwhile, much of the rest of the grain of China and India is fed by water that has for years been pumped from ancient underground aquifers faster than it can be replaced.
"The water tables under both the main grain-growing regions irrigated this way, the North China Plain and the Punjab, are sinking," said Brown.
"Losing both sources of irrigation could lead to politically unmanageable food shortages, especially since rising populations in both countries require more food production, not less," he said.
According to Brown, in India, where just over 40% of all children under five years of age are underweight and undernourished, hunger will intensify and child mortality will likely climb.
"The world has never faced such a predictably massive threat to food production as that posed by the melting mountain glaciers of Asia," he added.
"The alternative to this civilisation-threatening scenario is to abandon business-as-usual energy policies and cut carbon emissions 80% by 2020," said Brown.