It’s NBC’s annual global warming scare week, and one of the items mentioned was the receding glacier of Mount Kilimanjaro. So I decided to find out why. It seems most likely that lack of precipitation and evaporation are the causes, since the average temperature high on mountain is below freezing. Climate Audit has a nice article on the subject, and one of the comments made a good point about disappearing ice:
How do you ice cubes disappear in your frost free freezer. Global warming?
Another possibility, which is talked about in that article and in others I've read, is the reduction of forests surrounding the mountain. As stated on National Geographic:
According to Hardy, forest reduction in the areas surrounding Kilimanjaro, and not global warming, might be the strongest human influence on glacial recession. "Clearing for agriculture and forest fires—often caused by honey collectors trying to smoke bees out of their hives—have greatly reduced the surrounding forests," he says. The loss of foliage causes less moisture to be pumped into the atmosphere, leading to reduced cloud cover and precipitation and increased solar radiation and glacial evaporation.
That makes sense - less cloud covers means more sunlight reaches the ice leading to fast evaporation. But would that cause such a dramatic decline in glacial ice? Of course, being National Geographic, it goes onto to tell a doomsday story about how the glacier will disappear because the earth is heating up, which is not true - temperatures have been declining in recent years. And note what the World Climate Report mentions:
Consider that, for example, between 1953 and 1976—a period of global cooling—a full 21% of the glacier’s original area disappeared, as Thompson reported in 2002. Where were the dire forecasts of disastrous results from global cooling? At the time, it would have been completely logical (if ultimately false) to predict the following: “If this cooling trend continues, Kilimanjaro’s glaciers will completely disappear by 2015.”
So the reduction started long before the widespread destruction of the local forest – it actually started in the 19th century. It seems more likely that global weather patterns are to blame for the receding glacier, and since that is something we can't change, maybe we should not cause radical changes in our economic policy and lifestyle which would make zero difference to the environment.