Kilimanjaro's Glaciers May Last Longer Than Predicted
for National Geographic News
|May 1, 2007|
The fabled snows of Tanzania's Mount Kilimanjaro may not succumb to global climate change as quickly as scientists had feared.
A joint Austrian-U.S. research team that took seven years of measurements from weather stations atop Africa's tallest mountain says that its ice fields will be around for another 30 to 40 years, while the glaciers on its slopes could last even longer.
Kilimanjaro's icepacks have been retreating since the 1800s, but "the vanishing of those glaciers between 2015 and 2020 as reported some years ago is definitely unrealistic," said study participant Thomas Moelg of the University of Innsbruck.
That's good news for Tanzania's tourism industry. Thousands of tourists visit Kilimanjaro each year, and officials worry that many of these visitors will head elsewhere if the 19,340-foot (5,895-meter) peak's ice disappears (Tanzania map).
The research team found new evidence showing that lower precipitation—and not rising temperatures on the summit—is the main cause for the Kilimanjaro glaciers' retreat.
The abundant snows needed to maintain the ice fields come from weather patterns that form in the Indian Ocean. A computer simulation of weather patterns since the year 1500 showed that such systems have formed less often in recent years.
The mountain's ice, for example, retreated by about a foot and a half (a half meter) each year starting in 2000, when the researchers began taking measurements. (Related story: "Mount Kilimanjaro's Glacier Is Crumbling" [September 23, 2003].)
The glaciers now measure about 0.8 square mile (2 square kilometers), down from 4.6 square miles (12 square kilometers) in 1912.
But in 2006 an El Niño weather pattern helped bring heavy snowfall that almost buried weather stations on Kilimanjaro. The storms also thickened the peak's glaciers, increasing their thickness even though their surface area stayed the same.
El Niño had been known to bring more precipitation to low-level ecosystems in East Africa. But the finding that it did the same at higher altitudes is new.
The findings push back slightly the date the mountain is expected to completely lose its ice, the researchers say.
The research was announced at the annual assembly of the European Geosciences Union in Vienna in mid-April and will soon be published in the International Journal of Climatology.
The scientists say that the Kilimanjaro glacier findings emphasize another way that global warming is affecting the world.
So far many experts have focused on the impact caused by rising sea levels and temperatures. But less has been said about the effects of lower precipitation.
Kilimanjaro's shrinking glaciers buttress evidence that East Africa is drying out. And that's a phenomenon that needs to be studied further, researchers point out.
"It is quite difficult on a regional scale to say just why there is less precipitation in East Africa," said Julian Dowdeswell, director of the Scott Polar Research Institute at the University of Cambridge in England.
"We just don't know. It's at a scale that's difficult."
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