At the Great Aletsch Glacier

It’s quiet. A few birds and some brave hang gliders circle overhead. All we can hear are quiet conversations nearby. A vast glacier lies before us. It makes you feel very small. What a beautiful sight, and what an incredible thing nature has created here.

The glacier in front of us is the largest and longest glacier in the Alps. It is in the canton of Valais in Switzerland. It is called the Great Aletsch Glacier. It is 22.75 kilometres long and covers an area of 81.7 square kilometres.

It originates at Concordia Place at an altitude of 3,800 metres. This is where three mighty ice streams meet. From Concordia Place, the glacier then moves southeast towards the Rhone Valley, about 1.5 kilometres wide and at a speed of up to 180 metres per year. In a large right-hand curve, it turns increasingly southwest, separated from the Rhone Valley only by the ridge of Eggishorn and Bettmerhorn. The glacier tongue currently lies at an altitude of around 1,560 metres, well below the tree line. The Massa stream rises from it and flows into the Rhone after 7 kilometres; in Switzerland, the river is also called the Rotten.

Like all the others, the Great Aletsch Glacier is losing area and mass. Since 1850, its ice thickness has decreased by over 100 metres in some places; back then, the glacier tongue extended another 2.5 kilometres down the valley.

Our glaciers today formed during the last Ice Age. Temperatures were only a few degrees lower than they are today. Snow fell in winter and settled on the ground, becoming compacted. If the sun was not strong enough to melt this layer in summer, more snow fell on top of it the following winter. This created an ever-thickening mass of ice, which built up to heights of 3,000 metres over several millennia.

  In warmer periods, they shrank; in cold periods, they grew again. In mountainous regions, glaciers moved into valleys and hollows under their own weight, growing ever larger as a result. They scraped and pushed broad valleys into the mountains. The ice melted, and the water became a river that flows from the glacier through the valley towards the sea.

During the last million years, there were four ice ages in the Northern Hemisphere. During these ice ages, vast areas of Europe and North America were covered by glaciers. Many glaciers formed in the mountains, but most have since disappeared. Today, we find glaciers in Europe mainly in Norway and Switzerland. The largest Swiss glaciers are the Great Aletsch Glacier, the Gorner Glacier and the Fiescher Glacier. In Germany, only five glaciers remain, including the Northern and Southern Schneeferner below the Zugspitze.

During warm periods, glaciers retreated or disappeared altogether. During colder periods, they grew and spread. But for several decades now, we have been able to observe that the total area covered by glaciers is shrinking very quickly. Between 1850 and 2005, the area of Germany’s glaciers decreased by 60 percent. This is certainly partly due to a natural rise in temperatures. But over the past 200 years, the effects of industrialisation and the growth in the world’s population have also played a part. Burning wood, coal, gas and oil releases carbon dioxide. It rises into the atmosphere. Although it lets sunlight through to the Earth, it traps the heat that would otherwise escape from the Earth into cold outer space. This creates a greenhouse effect, causing the Earth’s temperature to rise even further. Researchers fear that many glaciers will disappear over the coming decades. This also poses a threat to our water supply. About 70 percent of the Earth’s freshwater is held in glaciers. So when glaciers melt, we lose vast reservoirs of water, and freshwater mixes with the oceans’ salt water. Sea levels will also rise, putting land just a few metres above sea level at risk of flooding.