Monday, November 30, 2009

Mapping India: Land Degradation and Desertification

In the November 25 issue of Current Science, researchers from the Indian Space Research Organization release a map and some important estimates of the extent of land degradation and desertification affecting mainly dry, semi-arid and dry- sub humid areas of India.

Source: Desertification/land degradation status mapping of India

About 69% of the total land area of the country - about 228 million hectares - falls in one of these three climatic categories. The numbers from this mapping project is cause for concern. They indicate that land degradation has affected just under half the extent - 105 million hectares of these dryland regions,  roughly 32% of the land area of India.

The main processes of degradation are water erosion, wind erosion and vegetal degradation through deforestation and overgrazing. The paper gives the extents affected by various degradation processes grouped state-wise.

I wish they had included estimates of degradation by land use. For example how much of agricultural land in each state is being degraded, how much forest and so on. These have been no doubt calculated. They show up as classes on the map, but the paper does not present the results by type of land use affected.

If predictions about changing rainfall patterns over India because of climate change turn out to be accurate they will accentuate many of these degradation processes. Rainfall is predicted to fall in shorter more intense bursts over many regions of India. This would mean more powerful surface runoff and greater soil erosion.

Regions of country which are hot and arid like Gujarat and Rajasthan are likely to get hotter and drier. That would mean more stress on vegetation and great wind erosion.

I come back to the National Action Plan For Climate Change (15 MB) There are 8 missions or strategies to deal with climate change. None of these directly includes the problem of land degradation and desertification in dryland regions. However the National Water Mission, National Mission for a Green India and the National Mission for Sustainable Agriculture seem to have the right overlapping goals that could be focused to address this problem.

I mentioned earlier about the estimates of land degradation according to land use. These numbers matter a lot. Farmers occupying dryland regions are usually poor farmers cultivating marginal lands. If you look at the above map, you will see large regions classified as Agriculture Unirrigated being affected by various processes of land degradation. These are farmlands that are out of the reach of irrigation canals and other State largesse.  Millions of farmers cultivate small land holdings, depending only on monsoons and groundwater. Warming and changing rainfall patterns will have a larger impact on these marginal farmers. Their livelihoods and the food security for large number of people in these drylands is at risk from continuing damage to the land.

The National Action Plan For Climate Change needs to single them out for special help.

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