Kilimanjaro Glaciers: Recent areal extent from satellite data and new interpretation of observed 20th century retreat rates

Recent and long term variations in ice extent on Kilimanjaro are investigated in the context of 20th century climate change in East Africa. Quickbird satellite data show that the areal extent of glaciers on Kilimanjaro is 2.51 km² in February 2003. To assess glacier retreat on Kilimanjaro two glacier systems are identified: (1) plateau (≥5700 m) and (2) slope (<5700 m). Vertical wall retreat that governs the retreat of plateau glaciers is irreversible, and changes in 20th century climate have not altered their continuous demise. Rapid retreat of slope glaciers at the beginning of the 20th century implies a strong departure from steady state conditions during this time. This strong imbalance can only be explained by a sudden shift in climate, which is not observed in the early 20th century. Results suggest glaciers on Kilimanjaro are merely remnants of a past climate rather than sensitive indicators of 20th century climate change.