Climate change causes (some) glaciers to grow

Increased precipitation in the "Southern Alps" as a cause

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It sounds paradoxical, but at least in some regions of the world the glaciers are still growing despite climate change. Such an exception was discovered by a German geographer in New Zealand. The reasons for the unusual growth are the recently abundant precipitation in this area.

The ice on the polar ice caps melts, the sea level rises, glaciers disappear: Scenarios like these are present in all media as possible consequences of climate change. But not everywhere such pictures show themselves: In the Southern Alps on New Zealand the glaciers even grow strongly, as the Würzburg geographer Stefan Winkler could prove. As proof that climate change is not as bad as feared, he does not want his data interpreted.

Southern Alps as an exception

Stefan Winkler, a geographer from the University of Würzburg, spent two months in New Zealand as part of a project funded by the German Research Foundation (DFG), where he studied the glaciers of the Southern Alps. His result: "While in most high mountains, including the European Alps, there is currently a significant decrease in glaciers, the glaciers of the Southern Alps are a major exception. Here, the glacier fronts are clearly advancing."

Among other things, Winkler carried out precise measurements on various glacier fronts during his stay. He was able to show, for example, that the front of the well-known Franz Josef Glacier has advanced by 84 meters within the last twelve months; the neighboring Fox Glacier even advanced 89 meters over the same period. From the helicopter Winkler was able to see a clearly visible increase in the glacier areas in many areas of the Southern Alps.

Precipitation decisive factor

How can one explain this, at first glance, surprising result that seems to contradict current climate change? "The glaciers of the Southern Alps are very close to the coast. The climate there is characterized by extremely high rainfall, which often fall as snow even in summer, "says Winkler. The later converted to glacier ice snow amounts are so large that despite relatively high air temperatures glaciers exist and some can flow down to just 300 meters above sea level. Precipitation plays a much more important role in the mass balance of these glaciers, as in the maritime glaciers in Norway, which are also studied in the research project, than, for example, in the Alpine region. display

"Since in recent years, as in the 1980s and 1990s, snowfall in New Zealand has been above average, the glaciers have been able to grow and push forward, " Winkler continued. At the same time, the air temperatures did not deviate significantly from the normal values; an excessive "meltdown" was thus missing.

Glaciers react very differently

The development of the glaciers on New Zealand shows impressively that there is no "global" behavior of the glaciers, says the geographer. On the contrary, glaciers, which are often used as climate indicators, seem to respond very differently to identical climate changes. Why this glacier growth is not in general contradiction to the current climate change, but should be seen as its consequence. After all, most climate forecasts assume precipitation increases in offshore areas as global temperatures rise due to increased evaporation.

"If this precipitation falls as snow in coastal high mountains, glacier growth can result, " says Winkler. The consequences of the current climate change for the glaciers should therefore not be generalized. A finding, so Winkler, which is also important when it comes to the use of glacier melt water, to generate electricity in mountains.

(University W rzburg, 03.05.2007 - NPO)