In The Field

EGU: Mountain high, climate change

A record number of 9,000 or so scientist has come to the always charming Austrian capital of Vienna for this year’s general assembly of the European Geosciences Union, the biggest such meeting this side of the Atlantic.

In search of some local colour I went this morning to a session on climate and mountain hydrology. Vienna, just like Munich, Milan, Grenoble and many other cities in vicinity to the Alps, depends on drinking water from mountain streams and reservoirs. The Alps are in fact a water tower for all the surrounding lowlands; and although there is no real water shortage, Alpine regions are highly sensitive to climate change.

Bruno Schädler of the University of Bern in Switzerland explained that a two degree increase in average temperature is equivalent to a 360 metres decrease in altitude. Total glacier area in the Alps is likely to decrease by more than 50% under this pretty realistic scenario. Projections are that more winter precipitation will fall in the form of rain, and less as snow, and that increased evapotransporation will reduce the amount of summer rainfall. All this will change the runoff regimes of Alpine rivers and streams, and hence the availability of water competing purposes including irrigation, hydropower, and tourism. But how, where and when these changes will come, and if they will bring more floods, or more low water, or both, is still extermely difficult to say. Regional climate models, for example, don’t represent complex Alpine topography, hydrology and meteorology, which differ from one valley or catchment area to the next.

Perhaps that explains why there is little, if any, adaptation to climate change happening in the Alps. Indeed, adaptation measures are driven by concrete events and economic requirements – such as lack of snow in a skiing ressort – rather than by climate change predictions. This is the result of ongoing regional case studies in six Alpine regions of Austria, Slovenia, Italy, France and Switzerland. Planning and management tools which consider climate change are almost totally absent, found Andrea Prutsch of Austria’s federal environmental agency, who coordinats the studies. Water-consuming artificial snow making is just one example of frequently happening cases of ‘maladaptation’. By and large, she said, adaptation to climate change in the Alps suffers from a widespread lack of data, monitoring and knowledge.

The science of climate change has come a long way. But this little Alpine saga shows that it has not yet arrived in the centre of society.

Quirin Schiermeier

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