The terms desertification refers to degradation of land in arid, semi-arid and sub-humid areas resulting from various factors, including climatic variations and human activities. It does not imply loss of land to desert or through sand-dune movement. Land degradation occurs everywhere, but is known as desertification when it occurs in the dryland ecosystems, i.e. land areas where the mean annual precipitation is less than two thirds of potential evapotranspiration (PET = potential evaporation from...
Desert ecosystem, is usually believed to be barren, but this fragile ecosystem supports numerous amazing living creatures, known for their adaptability.
In the present, the top three environmental issues facing the Thar are water availability, land quality and dust emission. While dwindling water reserves call for urgent attention to water management, threats of global warming and population pressure are not only deteriorating the land condition, but also increasing the sand mobility and atmospheric dust load.
The vulnerability of drylands is now markedly visible with acres of cropped land degraded. The 1977 Landsat MSS image, shows Ghaggar Diversion Channel bringing excess water of Ganga Canal to the interdune plains. The fertile valley of the Drishadvati palaeo channel, with crop lands depicted in blue, covering about half the image can be seen. The 2000 Landsat ETM image shows the same area where the Drishadvati palaeochannel is full of water that seeped out of the flooded interdunes. Milky white tone is indicative of the salinity developed due to waterlogging while red, indicates cropped lands, which show a steep decline from the previous image.