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-
Figure 6B.9: Glaciers as source for hydropower
tion of climate change – they also have the potential
production. A dam at Gries Glacier in Switzer-
of having a strong impact on the seasonal availability
land has been constructed to receive meltwater in
summer for use in power generation in winter.
of fresh water for large, densely populated regions
Photo: Jürg Alean, SwissEduc (www.swisseduc.ch)/Glaciers
and, hence, on the fundamental basis of ecosystem
online (www.glaciers-online.net) stability and economic development
56,73
.
CHAPTER 6B GLACIERS AND ICE CAPS 129