I was recently asked to comment on the new Science paper by Maurer et al on rates of glacier mass loss in the Himalayas. The paper is a great example of an expanded analysis that builds on previously developed techniques. The authors use declassified spy satellite imagery to create 1970’s era elevation models of glaciers along a 2000 km transect of the Himalayas. By comparing these with contemporary elevation models they are able to demonstrate that rates of glacier mass loss have doubled between 1970-2000 and 2000-2018. Based on the coherent signal of change between periods they also suggest that it can only be due to increased temperatures.
My comments appeared in a number of places, including:
What’s really encouraging to me is that our synthesis chapter on the status of the cryosphere in the Hindu Kush Himalaya (Bolch et al.) showed similar rates and acceleration of glacier mass loss, but was based on published mass balance rates (glaciological and geodetic). Our averaged rates of mass loss pre-2000 and post-2000, compared with Maurer et al:
Pre-2000 mass loss (m w.e.): -0.22 (Maurer) // -0.26 (Bolch et al.)
Post-2000 mass loss (m w.e.): -0.43 (Maurer) // -0.37 (Bolch et al.)
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