Himalayan glaciers aren’t shrinking as fast as thought – indeed, some are actually growing.
An international team of researchers took all the existing measurements of length, area and volume changes and mass budgets into account for their study. They included satellite data from the Shuttle Radar Topographic Mission (STRM) and the Satellite Pour l’Observation de la Terre (SPOT5).
And they recorded decreases of just 0.1 to 0.6 percent per year in recent decades, with glacier surfaces dropping by around 40 centimetres a year.
“The detected length changes and area and volume losses correspond to the global average,” says Tobias Bolch of the University of Zurich.
“The majority of the Himalayan glaciers are shrinking, but much less rapidly than predicted earlier.”
In central Karakoram, though, glaciers were seen to buck the trend, rising by about 11 centimeters a year, presumably because of the local microclimate.
Based on their analysis, the researchers say that theshrinkage shouldn’t have a major impact on the water drainage of large rivers like the Indus, Ganges and Brahmaputra.
They are concerned, though, by what they see as a very serious threat to the local population: newly formed or rapidly growing glacial lakes. The deluge of water and debris from potential outbursts of these lakes could have devastating consequences for low-lying regions, they say.