Permafrost

Europe's Big Melt Underway
Far News, January 16, 2000

Researchers have discovered that Europe's permafrost, the frozen bedrock on which the Alps rest, is melting. Underground ice temperatures rose by more than a degree in the '90s, threatening widespread devastation within the next two decades. Foundations of cable car stations face collapse; mountain slopes, held together by frozen soil, are likely to be swept down valleys; and rock faces will disintegrate. Already several recent Alpine disasters, including the avalanches that killed more than 50 people at the Austrian resort of Galtur last year, are being blamed on the melting of permafrost, scientists say.

"It is now clear that rises in atmospheric temperatures are producing significant changes in permafrost levels," said geologist Charles Harris of Cardiff University. "Global warming is changing the nature of weather systems and this is having disproportionate effects on temperatures underground." Atmospheric temperatures round the world rose about 0.2 degrees Celsius last decade, producing a spate of observations about the effects of warming, including signs that Europe's glaciers are shrinking. But now engineers and geologists have discovered a new, alarming effect: air temperature increases are being magnified fivefold underground. A test bore hole, dug in Murtel in southern Switzerland, has revealed that frozen sub-surface soils warmed by 1.2 degrees since 1990. We are getting earlier falls of snow which provide blankets of insulation that keep the soil warm," said Harris. "Summers are also warmer and are heating up the ground more."

To try to predict the worst effects, scientists backed by European Union funds have launched a program, Permafrost and Climate in Europe (Pace), to provide a continent-wide survey of threatened permafrost, which is concentrated in Scandinavia, the Alps, the Pyrenees and the Sierra Nevada in Spain. A series of bore holes is being drilled in these areas, and scientists are developing techniques for predicting the effects of permafrost loss on slopes and valleys. A key, and unexpected, instrument in this work will be the centrifuge. "When you spin things round and round very quickly, you create very powerful gravitational fields, and when you place objects in these fields the effects of gravity are speeded up," said another Pace researcher, civil engineer Michael Davies of Dundee University. "We are now building model valleys, and will put them in centrifuges to study what happens when soil is warmed up and the permafrost, which holds the ground together, is destroyed. We will simulate landslides and avalanches." The aim is to find out how to spot early signs of the imminent collapse of buildings and valleys, he said. "Racks and strains, the first evidence that cable stations and other buildings are under threat, may be easy to spot. This gives engineers an opportunity to put things right."

On the other hand, the recent wave of avalanches in the Alps suggests it will be a trickier job to spot valley walls and rock faces that are about to crumble and disintegrate. There is no doubt that there is a real danger to human life, thanks to permafrost warming," said Harris. "We want to minimize the destruction."