SafariLands.org: Environment: Mt Kilimanjaro ice still baffles experts

Mount Kilimanjaro one of the attractions that has brought in tourists from around the world, also the tallest Mountain in Africa.

A new study on the dwindling icecap of Africa's highest peak, Mount Kilimanjaro, suggests that global warming has nothing to do with the alarming loss of its beautiful snows. Scientists who carried out the research, Philip Mote and Georg Kaser. assertively link the loss of the icecap to a process called "sublimation." The former is a climatologist with the US's Washington University in the US and the latter a glaciologist with Austria's Innsbruck University.

The latest science literature on climate and glacier formation defines sublimation as a process that occurs at below-freezing temperatures and converts ice directly to water vapour without going through the liquid phase. Mote likens the process to moisture-sapping conditions that cause food to suffer freezer burn.

On revealing the findings they first published recently in the American Scientist magazine, the experts caution that, using the mountain in northern Tanzania as a 'poster child' for Climate Change is awfully inaccurate.

"There are dozens, if not hundreds, of photos of mid-latitude glaciers you could show where there is absolutely no question that they are declining in response to the warming atmosphere. But in the tropic, particularly on the Kilimanjaro, processes are at work that are far different from those that have diminished glacial ice in temperate regions closer to the poles," says Mote in revelations that caught many climatologists and glaciologists around the world by surprise.

The two experts now want the world to dash out the old assertions and believe that the ice loss on Kilimanjaro is mainly thanks to sublimation, which requires over eight times as much energy as does melting.

They state that the decline in Kilimanjaro's ice has been going on for more than a century and that most of it occurred before 1953, while evidence of atmospheric warming being there before 1970 is "definitely inconclusive".

Mote and Kaser attribute, the ice decline primarily to complex interacting factors -among them the vertical shape of the ice's edge, which allows it to shrink but not expand.

They also cite decreased snowfall, which reduces ice buildup and determines how much energy the ice absorbs. This is because the whiteness of new snow reflects more sunlight and the lack of new snow allows the ice to absorb more of the sun's energy.

The scientists say unlike mid-latitude glaciers, which are warmed and melted by surrounding air in the summer, the ice loss on the Kilimanjaro is driven strictly by solar radiation,.

They also maintain that, since air near the mountain's ice almost always is well below-freezing, "there typically is no melting".

They claim that fluctuating weather patterns relating to the Indian Ocean also can affect the shifting balance between the ice's increase, which may have occurred for decades before the first foreign explorers reached the mountain's summit in 1889, and the shrinking that has been going on since.

They say glaciers in more temperate latitudes have declined sharply as the troposphere - the troposphere is the atmospheric layer from the Earth's surface to about 10 miles in altitude - around them has warmed.

They cite an ice-glacier declining because of atmospheric warming at the South Cascade Glacier in Washington State, believed to be the most-studied glacier in North America, as the best example to prove their case.

Mote says photographs by scientists in 1928 and 2000, along with detailed surveys, showed that the glacier lost half its mass during that time and similar evidence exists for a number of other glaciers.

But in their analysis of their research, Kaser and Mote say the same factors do not apply to Kilimanjaro's icecap although its decline has been cited in forums such as the Academy Award-winning documentary film 'An Inconvenient Truth'.

"There is no evidence to support that assertion," Mote notes, adding: "It's not that it is impossible but rather the decline is most likely associated with processes dominated by sublimation and with an energy balance dominated by solar radiation rather than by a warmer troposphere."

According to the climatologist: "It is certainly possible that the icecap has come and gone many times over hundreds of thousands of years but for temperate glaciers there is ample evidence that they are shrinking, in-part because of warming from greenhouse gases."

Mote further notes that the level of nearby Lake Victoria, the world's largest tropical freshwater lake, also declined in the late 19th century - when the decline of Kibo's icecap began.

He says the lake and the icecap likely suffer from a precipitation decline caused by Indian Ocean variability, which could also have caused the icecap to vary in size and shape over millennia.

Herbert Hambati, a researcher at the University of Dar es Salaam's Geography Department, reacted to the findings by Mote and Kaser by pointing out that Tanzanian scientists need to do their own research on the duo's claims.

Hambati, who granted The Guardian an exclusive interview at the university on Friday, said the new findings could be true "but local researchers need to do their own study on the case".

"I urge Tanzanian scientists to take these findings as a challenge but we need to evaluate them and satisfy ourselves that they are correct," explained the lecturer.

Various sources about the Kilimanjaro indicate that the volcano Kibo is the highest point on the mountain - at about 19,340 feet above sea level.

A rough survey in 1889 suggested that Kibo's icecap occupied about 12.5 square miles. By 1912 it had dwindled to about 7.5 square miles, by 1953 it had shrunk to about 4.3 square miles, and by 2003 it was at just a little more than 1.5 square miles.

The Guardian Monday, November 26, 2007