“Mote and Georg Kaser, a glaciologist at the University of Innsbruck in Austria, write in American Scientist that the decline in Kilimanjaro’s ice has been going on for more than a century and that most of it occurred before 1953, while evidence of atmospheric warming there before 1970 is inconclusive.
“They attribute the ice decline primarily to complex interacting factors, including the vertical shape of the ice’s edge, which allows it to shrink but not expand. They also cite decreased snowfall, which reduces ice buildup and determines how much energy the ice absorbs — because the whiteness of new snow reflects more sunlight, the lack of new snow allows the ice to absorb more of the sun’s energy.
“Unlike midlatitude glaciers, which are warmed and melted by surrounding air in the summer, the ice loss on Kilimanjaro is driven strictly by solar radiation…
Read more here: http://www.physorg.com/news100885146.html
And Real Climate had an article on tropical glacier retreat way back in May 2005: