Warning in new report: Water crisis, threat to food security if India doesn’t act now

The world sat up and listened when the Intergovernmental Panel on Climate Change, in its report released last week in Paris...

The world sat up and listened when the Intergovernmental Panel on Climate Change (IPCC), in its report released last week in Paris, said that climate change was real and man-made. If this first chapter — people have begun calling it a doomsday scenario — was worrying, the real wake-up call will be in the IPCC’s second report which will deal with impacts of climate change and vulnerabilities of different regions of the world.

While the language and fine print will be debated and voted before the report’s final release in Brussels this April, the scientific findings are unlikely to be different from the background papers presented by 25,000 scientists for the preparation of the report. The Indian Express had a sneak preview of some of the papers from India that will form the chapter on Asia and found that climate change is more real and closer home than ever before.

The first report said that temperatures in the next century are expected to go up by 2.5 to 4.5 degrees Centigrade. What does this exactly translate for India? Most figures add up to a serious shortage of water and threat to food security. It just might be the wake up call that policy-makers in India need.

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These findings are for 2030, a little more than two decades away:

• Himalayan glaciers will shrink from 500,000 sq km to 100,000 sq km

• Per capita availability of water will shrink from 1,800 cubic m to 1,000 cubic m, making India a water-scarce country n Agriculture productivity is likely to shrink by 30%

Among the plethora of climate change studies over the last decade, these figures will assume added importance after getting the legitimacy and mandate of the top-most scientific panel on climate change.

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Availability of water: The most serious potential threat arising from climate change in Asia is water scarcity which in some way trigger other impacts, like fall in agriculture productivity. In absolute sense, India as a whole is likely to move from the category of water-stressed to water-scarce.

For a population estimate of 1800 million in 2050, the gross per capita water availability will decline from less than 1800 cubic metre per year in 2001 to 1000 cubic m. Internationally, less than 1700 m 3 /person/yr is “water-stressed” and less than 1000 m is “water scarce”’, India is water-stressed today and is likely to be water-scarce by 2050.

With 50 per cent of the water coming from glacier melt, the news that they will be reduced to one-fifth of their size shows the impact on hydrological system and water resources in India.

Rising temperatures mean that not only will there be more rain and less snow in the mountains, but also snow will melt earlier in the year. The result: rivers originating in the Himalayas will carry more water much earlier than normal. There will be more water in early summer, thinning before September. With glaciers vacating large stretches of land, this will contribute to increase in flood frequency and landslides in the Himalayan foothills.

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This scenario for Himalayan rivers will continue for about 50 years and then get reversed once the glaciers deplete completely. Scientists have not presented data beyond 50 years as uncertainties grow beyond this time scale.

As a result of change in precipitation, the annual mean surface flow in river basins in Krishna, Pennar, Cauvery, Luni, Tapti, Narmada, Mahi and Sabarmati river basins will decline, implying that water resources in these river basins will become scarce due to enhanced vulnerability by mid-21st century.

“Current policies affecting water use, management, and development in India are unresponsive to changing climate,”’ said Murari Lal, one of the lead authors of working group II and former IIT professor who’s now with Halcrow consultants.

In short, this change challenges the functioning of the existing water infrastructure and water management practices.

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Food security: Projected surface warming and shifts in rainfall are expected to lead to a substantial decrease in agricultural crop productivity. It is the subsistence farmers and marginal crops that will be the hardest hit.

According to Asian scientists, a two degree increase in surface air temperature would mean a fall in yields between 4% to 34% for mid-21st century.

The key finding is that small holders and subsistence farmers are likely to suffer complex, localized impacts of climate change. These groups, whose adaptive capacity is limited, will first have to cope with falling yields, droughts and floods. In the longer term, there are likely to be additional negative impacts of other climate related processes especially in the Indo-Gangetic plain.

Marginal crops like sorghum and millet could be at the greatest risk, both from drop in productivity and loss in crop genetic diversity.

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Agriculture irrigation demand in arid and semi arid regions of Asia is expected to increase by 10% for a temperature increase of 1 degree Centigrade. This could incur loss in farm level net revenue of between 9% and 25%.

The silver lining: there is enough evidence to show that if governments take adaptation measures early, most impacts become manageable.