Retreat of an Alpine glacier
Background
With a total length of almost 23 kilometers and an area of approximately 80 square kilometers, the Aletsch Glacier is the largest glacier in the Alps. Its ice reaches a thickness of up to 900 meters, forming a frozen river that winds its way through the rugged mountain landscape.
The effects of climate change are taking a toll on the Aletsch Glacier. Over the past century, it has been retreating at an increasing rate of about 100 meters per year. Rising global temperatures are causing the glacier to lose more ice through melting than it gains through snowfall. This imbalance threatens not only the glacier’s size but also the ecosystems that depend on it.
Satellite imagery has been instrumental in monitoring the Aletsch Glacier’s changes. These images provide a clear visual record of the glacier’s retreat and allow scientists to quantify its decline. Since the 1980s, satellite data has shown that the Aletsch Glacier has lost almost 2 kilometers in length, highlighting the urgency of addressing climate change.
Exercises
- Satellite Map:
- Look at the satellite image maps and select the true colour satellite image from 2022. Which land cover classes can you identify in the image?
- Zoom into the region, where the three large ice flows merge to form the Aletsch Glacier. Try to identify important features of the glacier, such as moraines.
- Zoom out again and switch the satellite image from 2022 off an on again. Compare with the satellite image from 1985. Which differences can you identify?
- Zoom to the end of the glacier and estimate the distance the glacier tongue has receded since 1985.
- Deselect the layer group “True colour” and compare the false-colour infrared representations of the glacier. in this band combination the ice of the glacier is very well visible, making it easier to determine its extent.
- How can the changes in the glacier extent influence the wildlife in this region?
- How do they affect the people living there?
- EO Browser:
- Open the EO Browser.
- Find the most recent Sentinel-2 dataset covering the area displayed in the satellite map. Is it easy to find (more or less) cloud-free images? Why/why not?
- Select a true colour visualisation.
- Can you identify additional, recent changes in the area (check e.g. the ice of the glacier)?
- Select the false colour infrared representation. Can you identify the land-use of the most intensely vegetated areas (represented by bright red colours)?
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