I learnt this listening to a Climate Scientist from Pollution Probe who hastened to add that other glaciers are melting because of global warming. He also made the point that environmental degradation is as much of a threat as global warming; so, his clarifying the real cause of snow loss of Kilimanjaro is actually important.
Below are links to reputable sources about deforestation causing snow loss at Kilimanjaro.
Dry Air the Kilimanjaro Culprit
International Journal of Climatology, 24, 329-339, doi: 10.1002/joc.1008, March 15, 2004
http://www.geo.umass.edu/climate/tanzania/pubs/kaser_etal_2004ijc.pdf"A drastic drop in atmospheric moisture at the end of the 19th century and the ensuing drier climatic conditions are likely forcing glacier retreat on Kilimanjaro."
Temperature Not the Driving Force
Journal of Geophysical Research - Atmospheres, 109, D16104, doi:10.1029/2003JD004338, August 25, 2004
http://www.geo.umass.edu/climate/tanzania/pubs/moelg_hardy_2004jgr.pdf"It has been speculated that general global warming is directly driving the retreat of Kilimanjaro's glaciers. However, detailed analyses of glacier retreat in the global tropics uniformly reveal that changes in climate variables related to air humidity prevail in controlling the modern retreat. ...
"In the context of modern glacier retreat on Kilimanjaro, a particular sensitivity of the summit horizontal glacier surfaces to precipitation variability (magnitude and timing) can be confirmed by this study. This fits well into the present knowledge of modern glacier retreat on Kilimanjaro and in East Africa in general, initiated by a drastic reduction in precipitation at the end of the nineteenth century."
Temperatures Remain Consistent
Bulletin of the American Meteorological Society, 84, S48, June 2003
http://www.geo.umass.edu/climate/tanzania/pubs/hardy_2003bams.pdf"Kilimanjaro's glaciers are extremely sensitive to precipitation variability, as on an annual basis, the summit climate is thermally homogeneous, with a mean annual temperature of -7.1 degrees Celsius."
Deforestation Causing Dry Climate
Nature, November 24, 2003
http://www.usenet.com/newsgroups/talk.environment/msg05757.html"Although it's tempting to blame the ice loss on global warming, researchers think that deforestation of the mountain's foothills is the more likely culprit. Without the forests' humidity, previously moisture-laden winds blew dry. No longer replenished with water, the ice is evaporating in the strong equatorial sunshine."