Prelims Level
Mains Level
Prelims Syllabus : Environment Climate Change and its Impacts Mains Syllabus : Conservation, Environmental Pollution and Degradation, Environmental Impact Assessment.


  • Comparing data obtained by Cold War• era spy satellites with images from modern stereo satellites have shown Himalayan glaciers are Melting.


  • During cold war Spy satellite war deployed by US, this satellite took images across the globe, now this image are compared to new images and global warming impact is studied.
  • US spy programme – code named Hexagon – launched 20 satellites into orbit to secretly photograph the Earth.
  • The research is published in the journal Science Advances.

Report Details:

  • Annual mass losses suggest that of the total ice mass present in 1975, about 87% remained in 2000 and 72% remained in 2016.
  • Similar mass loss rates across sub regions and a doubling of the average rate of loss during 2000– 2016 relative to the 1975– 2000 interval.
  • The study goes on to assert that rising temperatures are responsible for the accelerating loss.
  • The study rules out other causes for glacier changes, such as the deposition of soot on snow and ice and changing precipitation patterns.
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