Global Outlook for Ice & Snow

The shrinking and even vanishing of mountain gla- ciers in scenarios of atmospheric temperature rise is likely to cause both small and large meltwater streams to dry out during hot and dry summers. This drying out may become more frequent at mid-lati- tudes, where human populations are often dense and the need for fresh water is growing. Earlier snowmelt and perhaps also reduced snow cover from winter- time could result in severe consequences for both ec- osystems and related human needs: decreasing river flow, warmer water temperatures, critical conditions for fish and other aquatic forms of life, lower ground- water levels, less soil humidity, drier vegetation, more frequent forest fires, stronger needs for irrigation wa- ter, and rising demands for energy (such as air condi- tioning) coupled with reduced hydropower generation and less river cooling for nuclear power plants. These consequences are all likely to be interconnected and related to growing conflicts of interest. Perhaps the most critical regions will be those where large populations depend on water from glaciers dur- ing the dry season, such as in China and other parts of Asia, including India, together forming the Hima- laya-Hindu Kush region (see box on the water towers of Asia), or in the South American Andes 70 (see box on glaciers and water availability in the Andes, in Part 2 of this chapter). But it will also affect mountain rang- es which are densely populated and highly developed, such as the European Alps and the regions in the vi- cinity of its rivers 71,72 . Glacier changes, as important and pronounced parts of climate-induced changes in mountain landscapes, are not only the clearest indica- tion of climate change – they also have the potential of having a strong impact on the seasonal availability of fresh water for large, densely populated regions and, hence, on the fundamental basis of ecosystem stability and economic development 56,73 .

Figure 6B.9: Glaciers as source for hydropower production. A dam at Gries Glacier in Switzer- land has been constructed to receive meltwater in summer for use in power generation in winter. Photo: Jürg Alean, SwissEduc (www.swisseduc.ch)/Glaciers online (www.glaciers-online.net)

CHAPTER 6B

GLACIERS AND ICE CAPS

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