A glacier starts to melt...

While the temperature rose by a worldwide average of 0.74°C over the past century (1905-2005), it rose by 1.5°C in Switzerland during the same period! This has left its mark on the country’s glaciers – and more than one glacier has begun to melt.


Climatic fluctuations are natural


When we look at geological history, it becomes clear that the earth’s climate was never static. The alternation of warm and cold phases is a natural occurrence. The accompanying temperature fluctuations become visible in the amount of ice that covers the earth. Thus it is not unusual for glaciers to advance and then retreat again.



 

The ice ages enabled glaciers to grow


During past ice ages, the Great Aletsch Glacier united with the Rhone Glacier. The latter became the largest of all the Alpine glaciers and at its various peaks stretched almost to Lyon in France.



 

3 kilometers (1.8 miles) longer 150 years ago


Since the end of the last ice age, known as the Würm, a good 10,000 years ago, the Great Aletsch Glacier has been retreating. The climate has been warming up. However, this is only a trend, as there were also cooler periods such as the Little Ice Age (15th -19th centuries). During this period the Great Aletsch Glacier advanced slightly once more and achieved its last peak in 1860: it was three kilometers (1.8 miles) and up to 300 meters (984 feet) thicker than it is today.



 

Increasing retreat


Since then, more ice has been melting than has been formed at the higher altitudes: the Great Aletsch Glacier is retreating. At first the process was slow, but it is now speeding up. The following average reductions in length were established using data from the Swiss Federal Institute of Technology in Zurich:

 

1870 - 2008:

minus 24 meters (79 feet)

1970 - 2008:

minus 35 meters (115 feet)

1993 - 2008:

minus 49 meters (161 feet)

1998 - 2008:

minus 52 meters (171 feet)


Human activity is changing the climate


The rising speed of the retreat is an indication of today’s global warming. In contrast to earlier warming periods, this can no longer be explained only by natural causes. For some 250 years, humans have increasingly changed the composition of the atmosphere with greenhouse gas emissions, thus amplifying the natural greenhouse effect. 



 

Sweeping consequences


Higher temperatures, changes in precipitation, rising sea levels and disruptions in ecosystems – the habitat of millions of human beings, animals and plants is endangered. Because we humans are part of the cause of all this, we can all do something to prevent global warming by changing our behavior accordingly.