November 3, 2009

Scientists Say Kilimanjaro’s Ice Caps Rapidly Melting

The majestic snow-capped summits of Africa's Mount Kilimanjaro are melting quickly "” so quickly, in fact, that the ancient mountain's ice sheet could completely disappear within 20 years, says a US study released on Monday.

In the study, published in the journal Proceedings of the National Academy of Sciences, climatologists reported that the ice cap crowning Kilimanjaro's peak shrank by some 85 in the nearly hundred years between 1912 and 2007.  Even more disturbing,  however, is the fact that 26 percent of the reduction occurred in the short period from 2000 to 2007 "” an acceleration which they believe has been caused predominantly by global warming.

"This is the first time researchers have calculated the volume of ice lost from the mountain's ice fields," explained Lonnie Thompson, professor of earth sciences at Ohio State University and co-author of the study.

"If you look at the percentage of volume lost since 2000 versus the percentage of area lost as the ice fields shrink, the numbers are very close."

Though Thompson's team concedes that other factors such as relative cloudiness and levels of precipitation could also be playing a role, they say that these are likely minor factors compared to the effects of rising global temperatures.

"The fact that so many glaciers throughout the tropics and subtropics are showing similar responses suggests an underlying common cause," explained Thompson.

"The increase of Earth's near surface temperatures, coupled with even greater increases in the mid- to upper-tropical troposphere, as documented in recent decades, would at least partially explain the observed widespread similarity in glacier behavior."

Although the ever-retreating borders of the mountain's glaciers are the most dramatic and easily observable changes taking place, Thompson says that he is equally concerned about the less noticeable thinning of the ice sheets.  Both the Northern and Southern Ice Fields which crest the summit have thinned out by more than 6 feet and 16 feet, respectively.

But the most alarming loss of ice was observed on the smaller Furtwangler Glacier, which Thompson's team said had lost nearly half of its thickness between 2000 and 2009.

"In the future, there will be a year when Furtwangler is present and by the next year, it will have disappeared. The whole thing will be gone," said Thompson.

After examining the nearly 12,000-year-old ice core samples extracted from the glaciers, the research group said that they had been able to find no other instances of such prolonged and rapid ice loss.  They say that this points to the uniqueness of current temperature conditions around Kilimanjaro, corroborating the idea that current global temperature changes are not part of a larger phenomena of normal cyclical climate patterns.

The research was funded by the U.S. National Science Foundation and National Oceanic and Atmospheric Administration.


Image 1: Kilimanjaro's massive ice fields have begun eroding as global temperatures rise. Credit: Lonnie Thompson, Ohio State University

Image 2: The ice fields atop Tanzania's Mount Kilimanjaro glow golden in the last of the afternoon sun. Credit: Lonnie Thompson, Ohio State University

Image 3: One of a growing number of isolated remnants of Kilimanjaro ice spires, once full glaciers. Credit: Lonnie Thompson, Ohio State University


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