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Equatorial African icecaps melting awayPosted: 29 May 2006
Equatorial icecaps in the Rwenzori Mountains of East Africa will disappear within 20 years because of global warming, new research by British and Ugandan scientists projects.
In a paper published in Geophysical Research Letters, the researchers report results from the first survey of the Rwenzori glaciers conducted in a decade.
Field surveys and satellite mapping of these glaciers conducted by researchers from University College London, Uganda's Makerere University, and the Ugandan Water Resources Management Department show that some glaciers are receding tens of metres each year.
The Rwenzori Mountains are protected as a national park and as a UNESCO World Heritage site, but these designations cannot protect the glaciers from climate change.
(Photo courtesy UNESCO)
The researchers found that the area covered by glaciers shrank by half in the time period between 1987 and 2003.
An increase in air temperature over the past 40 years has contributed to a substantial reduction in glacial cover, they say.
Richard Taylor of the University College London Department of Geography, who led the study, says, "Recession of these tropical glaciers sends an unambiguous message of a changing climate in this region of the tropics."
Taylor and his colleagues found that since the 1960s in the Rwenzori Mountains, there are clear trends toward increased air temperature without major changes in precipitation.
"The rise in air temperature is consistent with other regional studies that show how dramatic increases in malaria in the East African Highlands may arise, in part, from warmer temperatures, as mosquitoes are able to colonize previously inhospitable highland areas," said Taylor.
He acknowledges that scientific debate still exists as to whether changes in temperature or precipitation are responsible for the shrinking of glaciers in the East African Highlands that also include Kilimanjaro [in Tanzania] and Mount Kenya.
The Rwenzori Mountains, also known as the Mountains of the Moon, straddle the border between the Democratic Republic of Congo and the Republic of Uganda, rising four kilometres above the surrounding plain. They hold one of four remaining tropical ice fields outside of the Andes.
These mountains shelter rare plants such as the giant heather and endangered animals such as elephants, chimpanzees, as well as 89 species of forest birds.
Their extensive snowfields produce meltwaters that supply a network of alpine rivers, lakes and wetlands that are a source of the River Nile. The meltwaters sustain agricultural production downstream and allow generation of hydroelectric power.
The mountains' legendary status was established during the second century, when the Greek geographer Ptolemy referred to the snow-capped mountains at the equator in Africa as, "The Mountains of the Moon whose snows feed the lakes, sources of the Nile."
The Rwenzori glaciers were first surveyed a century ago when glacial cover over the entire range was estimated to be 6.5 square kilometres [2.5 square miles]. With less than one square kilometre (0.5 square mile) of glacier ice remaining, the researchers expect these glaciers to disappear within the next 20 years.
Speke Glacier bounded by steep scarps within the Rwenzori Mountains National Park, Uganda in June 2003.
(Photo courtesy Richard Taylor)
World heritage site
The mountains are protected by UNESCO World Heritage status and by the Rwenzori Mountains National Park, covering nearly 100,000 hectares including Africa's third highest peak, Mount Margherita standing 5,109 metres (16,761 feet).
A key focus of the research is the impact of climate change on water resources in Africa. But the retreat of glaciers in the Rwenzori Mountains is not expected to affect river flow, the scientists say, due to the small size of the remaining glaciers.
It remains unclear how the projected loss of the glaciers will affect tourism and local traditional belief systems that are based upon the snow and ice, known locally as "Nzururu."
For centuries glaciers on the Rwenzori's summits have protected the BaKonzo indigenous people from being enslaved by neighboring tribes and from tropical diseases like malaria, Taylor says.
"Considering the continent's negligible contribution to global greenhouse gas emissions," said Taylor, "it is a terrible irony that Africa, according to current predictions, will be most affected by climate change."
Copyright Environment News Service (ENS) 2006. All Rights Reserved.
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