even entirely covered Scandinavia, lowering global sea many places, lakes have already started to form. Such
level by more than 100 m, greatly modifying coastlines lakes may replace some of the lost landscape attrac-
of all continents and dramatically affecting the cours- tiveness, but their beauty may come at a dangerous
es of large rivers and the global ocean circulation
60,61
. price (as explained above in the section on natural
This new knowledge constituted a fundamental break- hazards). On slopes, vegetation and soils take dec-
through in our understanding of the climate system as ades and even centuries or sometimes millennia to
an essential part of living conditions on Earth. Ice Age follow the retreating ice and cover the newly exposed
landforms have become a unique heritage, reminding terrain
64
. As a consequence, the zones of bare rock
us of the consequences of global temperature changes and loose debris will expand. Vegetation (especial-
of just a few degrees. ly forests) and ice both have a stabilizing effect on
steeply inclined surfaces. During the expected long
Curiosity and romantic enthusiasm characterize many transitional period between glacier vanishing and
historical reports and paintings of glaciers and high forest immigration, erosion (including large debris
mountain landscapes. Very often, glaciers are portrayed flows) and instability (including large rockfalls and
as an expression of ‘wild, non-destroyable’ nature, landslides) on slopes unprotected by ice or forest will
sharply contrasting with the cultivated landscape of hu- increase substantially
65
.
man habitats. Glacierized mountain areas therefore be-
came – and still are – major tourist attractions in many The perennial ice of glaciers is an important part
parts of the world. In fact, the ‘clean white of the eternal of the water cycle in cold regions. It represents a
snow’ on high mountain peaks is often seen as a beauti- storage component with strong effects on river
ful treasure and used as a precious symbol of intact en- discharge and fresh water supply
66,67
. Such effects
vironments
62
. This is why the current shrinking, decay indeed make high mountain chains ‘water towers’
and even complete vanishing of glaciers evokes such an for many large areas and human habitats. Climat-
emotional response. ic change will lead to pronounced changes in this
system
12
. At time scales of tens and hundreds of
Apart from their symbolic value, glaciers are also among millennia, the growth and decay of continental ice
the best natural indicators of climate change
12,20
. Their sheets, large ice caps and glaciers during periodical
development can be observed by everybody – and the ice ages profoundly affect the global water cycle
61,68
.
physical process, the melting of ice under the influence Within annual cycles of temperature and precipi-
of warmer temperatures, can intuitively be understood. tation, glacial meltwater feeds rivers during the
The impacts of accelerated atmospheric warming are warm/dry season. In the Andes of Peru, the Argen-
thus changing the public perception of glaciers: they are tinean Pampas or the Ganzhou Corridor of China,
increasingly recognized as a warning signal for the state this contribution to river flow is the predominant
of the climate system
63
. source of freshwater for large regions surround-
ing the corresponding mountain areas
69
. Meltwa-
Continued atmospheric warming will inevitably lead ter from glacierized mountain chains with rugged
to the deglaciation of many currently glacierized land- topography is also intensively used for hydropower
scapes, especially in low-latitude mountain chains. In generation (Figure 6B.9).
128 GLOBAL OUTLOOK FOR ICE AND SNOW