Dramatic changes are taking place in the glacier-covered high mountains of Africa. The glacial area on Mt Kilimanjaro is now only half as large as it was in the 1970s. The Tyndall Glacier on Mt Kenya, which retreated at approxi-retreated at approximately 3 m/yr from 1958 to 1997, retreated at about 10 m/yr from 1997 to 2002. Pioneer species such as Senecio keniophytum, Arabis alpina, mosses, lichen, and Agrostis trachyphylla have advanced over areas formerly covered by the glacier. The rate at which this vegetation migrated up the former bed of the glacier (2.1–4.6 m/yr from 1958 to 1997) is similar to the rate of glacial retreat (2.9 m/yr). In the interval from 1997 to 2002, pioneer species advanced at a rapid rate of 6.4–12.2 m/yr, while the glacier retreated at 9.8 m/yr. Rapid glacial retreat has been accompanied by rapid colonization by plants. Pioneer species improve soil conditions and make habitat suitable for other plants. If warming continues, alpine plant cover may extend all the way to mountain summits, and then eventually diminish as trees colonize the areas formerly occupied by alpine plants. Larger woody plants such as Senecio keniodendron and Lobelia telekii, which showed no obvious advance prior to 1997, have advanced quickly since that year.