by Staff Writers
Innsbruck, Austria (SPX) Feb 07, 2012
The composition of land surface - such as vegetation type and land use - regulates the interaction of radiation, sensible heat and humidity between the land surface and the atmosphere and, thus, influences ground level climate directly. For the first time, the Innsbruck climate scientists quantitatively examined whether land-cover changes (LCC) may potentially affect glacier loss.
"We used Kilimanjaro in East Africa as a test case, where a significant decrease of forests at elevations between 1,800 and 3,000 meters, caused by illegal deforestation and an increased number of forest fires, has been documented since the 1970s," explains climate researcher Thomas Molg, who has worked in Berlin since 1 October 2011 but finished the study with his team at the University of Innsbruck.
The glaciers in the Kilimanjaro area have been shrinking for many decades, and climate researchers from Innsbruck and America have conducted thorough glaciological and meteorological measurements for ten years -ideal prerequisites for carrying out a comprehensive study about a potential connection between forest loss and glacier shrinking.
"Based on this evaluation we then modified vegetation cover in the atmospheric model - first showing 1976 and subsequently the current state - and calculated its effect on glacier mass," says Thomas Molg.
The results show that LCC mainly alter precipitation over glaciers but with different effects on the Northern and Southern ice fields of the mountain (increase or decrease respectively), which results in local increase or decrease of glacier mass.
"Depending on the season, LCC contributes not more than seven to 17 % to glacier mass loss in the southern sector. We, therefore, cannot confirm the hypothesis that deforestation at Kilimanjaro contributes significantly to glacier loss," explains Thomas Molg.
Less precipitation in mid-mountain elevation zones
"However, another important aspect of the results is that deforestation decreases precipitation significantly more in mid-mountain elevation zones about two kilometers below the glacier than in summit zones". This affects local water reservoirs and reduces water supply for the local population.
University of Innsbruck
Beyond the Ice Age
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