Himalayan glaciers going nowhere
Researchers led by the University of Zurich in Switzerland andfunded by the EU have discovered that the Himalayan glaciers are inbetter shape than previously thought. The scientists claim thatprevious predictions made in the Intergovernmental Panel on ClimateChange (IPCC) overstated the decline of the Himalayan glaciers.
The results are an outcome of the
Detect change in an early stage
The state of the Himalayan glaciers is vitally important,considering that several hundreds of millions of people inSoutheast Asia depend, to varying degrees, on the freshwaterreservoirs that are provided to them. Given this significance,researchers believe that it is important to detect the potentialimpact of climate changes on the Himalayan glaciers at an earlystage.
For this reason the researchers teamed up with the European SpaceAgency to undertake the most up-to-date satellite surveying,revealing that the glaciers in the Himalayas and Karakoram cover atotal area of approximately 40.800 square kilometres.
While this is around 20 times larger than all the glaciers of theEuropean Alps put together, it is as much as 20% smaller than waspreviously assumed. Lead scientist Tobias Bolch, who conductsresearch at the University of Zurich and Dresden University ofTechnology in Germany, mainly put this down to erroneous mappingsin earlier studies. From this survey, the team concluded that theglaciers in the Himalayas are declining less rapidly than waspreviously thought.
Shrinking but not disappearing
‘The detected length changes and area and volume lossescorrespond to the global average,’ explained Dr Bolch, summarisingthe new results. ‘The majority of the Himalayan glaciers areshrinking, but much less rapidly than predicted earlier.’
For the purposes of their study, the scientists considered allthe existing measurements of length, area and volume changes, andmass budgets. However, it should be noted that continuousmeasurement data series do not go back further than 10 years. Theresearchers recorded average length decreases of 15 metres to 20metres and area decreases of 0.1% to 0.6% per year in recentdecades. Based on their analyses, the researchers assume thatglacier shrinkage will not have a major impact on the waterdrainage of large rivers like the Indus, Ganges and Brahmaputra inthe coming decades.
Greater seasonal variability
Despite the partial all-clear for the Himalayan glaciers,however, Dr Bolch advised caution: ‘Due to the expected shrinkageof the glaciers, in the medium term we can expect a greatervariability in the seasonal water drainage. Individual valleyscould dry up seasonally.’
That said, the scientists do see considerable hazard potentialfrom outbursts of glacial lakes. Dr Bolch and his colleagues alsosee a very serious threat to the local population in newly formedor rapidly growing glacial lakes. The deluge of water and debrisfrom potential outbursts of these lakes could have devastatingconsequences for low-lying regions. According to the scientists,increased efforts are urgently needed to monitor the lakes as wellas changes in the glaciers and the climate in the Himalayas.
