Retreat of a tropical glacier
Background
With its elevation of 5,895 metres, Mount Kilimanjaro in Tanzania is Africa’s highest mountain. During the last decades the famous glacier on top of the volcano has been significantly affected by climate change. Satellite images have revealed a dramatic decrease in glacier coverage. For instance, in 1912, Kilimanjaro had an estimated 12 square kilometres of glacier; by 2011, this area had shrunk to just 1.76 square kilometres.
Climate change has played a key role in this transformation. Average temperatures in the region have risen by approximately 0.3 °C per decade, causing the glaciers to recede. This retreat not only affects the water supply but also endangers the unique alpine flora and fauna that have adapted to these cold, high-altitude conditions.
Deforestation rates on the lower slopes of the mountain are also concerning. In the last several decades, Kilimanjaro has lost nearly 40% of its forest cover due to agricultural expansion and logging. This deforestation exacerbates soil erosion, leading to sedimentation in local rivers and threatening water quality. In 1973 the Kilimanjaro National Park was established to protect the forest belt surrounding the peak area of the mountain.
Exercises
- Satellite Map:
- Click on the layer selector icon in the upper right and deselect all layers by clicking on the respective boxes.
- Select the true colour satellite image from 1987. Describe the structures you can identify in the image. Where are mountains, glaciers, water bodies, vegetated areas?
- Compare the true colour satellite images from 1987 and 2023 and describe the changes in the glacier extents.
- Do the same for the false-colour infrared images. Can you identify anything new, e.g. with respect to the vegetation on the mountain slopes?
- Do the same for the third band combination for both years, which show the ice cover very clearly.
- EO Browser:
- Open the EO Browser.
- Search for the most recent Sentinel-2 satellite image covering the Kilimanjaro.
- Display the dataset in natural colours and compare it with the satellite images in the map above. What differences can you detect with respect to the images provided in the map above? What are the reasons for the differences?
