Several glaciers adorn the head of Mount Kilimanjaro; all are in rapid retreat. Glacial retreat is not itself a terrible thing. Glaciers naturally retreat every summer as warmer temperatures melt them; then they advance again in the cold of winter.
Due to human-induced climate change, however, glaciers all over the world are no longer regaining their winter weight after each summer slim-down. Year after year they recede more than they advance, not unlike Donald Trump's hairline.
Kilimanjaro in particular lost over 85% of its icy tiara during the 20th Century alone. More startling, 25% of what remained in 2000 has vanished in just the last 14 years, meaning that the speed of retreat is accelerating. In fact, the rate doubled in about half a century. To put it another way, twice as much ice has been lost in my lifetime as was lost during my grandfather's lifetime. Consequently, the summit will be bare rock within a few decades.
Ah, but there were only 2 billion puny humans on the planet back then.
By the time I read The End of Nature there were already 5 billion of us, many driving gas-burning cars and sucking huge amounts of electricity from coal-burning power plants.
Now there are more than 7 billion puny humans on planet Earth. And, man, do we generate a lot of atmospheric carbon!
Among the many powerful images Gore used to make his point was a set of before-and-after photos of Mount Kilimanjaro, documenting the rapid retreat of its glaciers. Since then, K-man has become something of poster-child for the cause, along with polar bears, coral reefs, and – let’s face it – Al Gore.
Just one problem: Turns out that the retreat of K-man’s glaciers is probably not directly related to global warming.
It certainly made sense at the time for Gore and Guggenheim to assume that K-man’s glaciers were falling victim to the same forces clobbering the world's other glaciers. But the filmmakers lacked one key piece of information about that particular mountain that only came to light later: Temps at the summit never rise above freezing.
Hard to make a case for melting with that hostile little data point on the table.
The biggest culprit, however, seems to be deforestation at the base of the mountain. As humans remove trees and other vegetation from the lower slopes, less humidity is available to rise up and condense into ice on the summit. This lack of humidity also results in less cloud cover, meaning that the glaciers receive many more hours of direct sunlight each year, thus causing even more ice to vanish in an evaporation-like process called sublimation.
Not surprisingly, climate change deniers pounced on the error. Deniers argued that since the film is wrong about Kilimanjaro's glaciers, then all of its claims are suspect.* They are not. In fact, a UK judge examined the film's claims and ruled in 2007 that it was worthy to be shown in British schools. That same year Al Gore was awarded the Nobel Peace Prize for his contributions to putting climate change on the global agenda. What's more, everything we've learned about Earth's climate since the film's release has borne out its portentous message.
Adding insult to injury, enormous amounts of valuable scientific information is being lost as the world’s glaciers thin and recede. Geologists can dig down into glaciers and read ice layers in much the same way that biologists read tree rings. The thickness and chemical composition of each layer tells us what the Earth was like in past epochs. What’s more, tiny air bubbles trapped in the ice can be extracted and analyzed, revealing the composition of the Earth’s atmosphere long before humans arrived.
In this way, K-man’s glaciers are like an archive of East Africa’s geologic and atmospheric history dating back nearly 12,000 years. There will be no recovering that information once the ice is gone, and I’m afraid that much of it is gone already. Losing Kilimanjaro’s glaciers is like burning the Library of Alexandria all over again. It's like watching some klutz drop the Rosetta Stone while lugging it over to the Translations Department.
In case you're wondering, the reason Kilimanjaro’s glaciers behave differently than other glaciers around the world has to do with the mountain's location at the Equator. Glaciers in temperate regions retreat in summer and advance in winter, but because K-man is smack in the middle of the tropics, temperatures on its summit differ more between day and night than they do between summer and winter. Therefore, there's no seasonal advance/retreat cycle to begin with. And that’s a pretty cool fact.
That fact would be a lot cooler if only those glaciers were disappearing at a more glacial pace.