The existence of glaciers in the Himalayas

At 4,300 meters above sea level, located in the western part of the Himalayas, it is easy to see a stretch of about 5 km of India's Jaundhar glacier, covered with a thick layer of broken rock.

An important part of the glaciers covering the Himalayas is now very stable and may be growing, thanks to an insulating layer of broken rock fragments, according to a new study.

The results of the new study, which is in stark contrast to the 2007 report by the Intergovernmental Panel on Climate Change (IPCC), have been withdrawn in 2009, because it exists many unconformities. physical.

Although the report said that the risk of the region's glaciers will " disappear by 2035 and perhaps earlier is very high ", the results of the new study found that the water layer freezes. It is very stable and growing, covering the mountains of Karakoram, a northern region of the Himalayas, containing about half of the Himalayas' frozen water reserves.

However, this does not mean that the water reserves in the area commonly known as the roof of the world are not under pressure. Throughout the Himalayas, about 65% of the glaciers in this study are shrinking, according to research by Dirk Scherler, working at Potsdam University, Germany and colleagues published online in magazines. Nature Geoscience . But in the Karakoram area, 58% of the glaciers in the study were stable or slowly expanded up to 12 meters per year.

Scherler's team focused on studying images taken from satellites of 286 glaciers in the Himalayas, from 2000 to 2008, that showed a consistent trend: " reduce the area of ​​ice cover ", everywhere in the Himalayas, except for the Karakoram area. Many glaciers in these regions are still stagnant, not even flowing, which is one of the reasons for reducing the area of ​​ice cover, according to Scherler.

The new findings are consistent with Kenneth Wilfrid Laurier Hewitt's observations, working at Wilfrid Laurier University, in Waterloo, Ontario, Canada and pointing out the fact that the picture of the effects of climate change in The Himalayas in Asia, are more complex than what most people can recognize.

Indeed, for centuries, the Karakoram glaciers have reduced the area of ​​ice covered, according to a 2005 article by Kenneth Wilfrid Laurier Hewitt. The change in the opposite direction completely began only in the late 1990s.

In the new study, Scherler's team is looking for factors that could affect the reaction of glaciers in the Himalayas with global warming.

In general, warm air temperatures above a glacier will melt the ice surface faster. The thin outer layer of dust or grit will melt glaciers, increase the amount of heat they absorb and amplify the heat, like a dark roof becoming hotter by sunlight than in rays bright gray. But once the thickness of any rock exceeds a few centimeters, unknowingly, the rocks will become insulation, helping the glacier not be affected by the sun. The glaciers in the Himalayas, especially in the Karakoram area, fragments of stone can reach the size of the house, according to Scherler.

According to this finding, it seems that fragments of broken rock originating from the upper mountain peak have become insulation, helping the glacier to be reduced to cover the ice area, unaffected by the impact of regional warming. The new analysis shows that the rate of reduction of ice cover is very different for the Himalayan glaciers " from glaciers that have reduced ice cover with high rates due to lack of protection. of broken rock fragments, until glaciers have a reduction in the area of ​​ice cover with zero, thanks to broken rock fragments covering more than 20% of the glacier . "

The data collected from satellites, useful for surveys of glacier coverage, are not sufficient to accurately assess the thickness or thinness of glaciers in each region. This information requires ground measurements, according to Hewitt. But they also provide quite important evidence. He notes that updated data from India and China show that diffuse radioactive dust of soot from local industries, traffic and stoves is covering the area of ​​the glaciers are not covered by broken rocks in the Himalayas, which is " an even more important factor than the temperature change, melting glaciers ".