Climate Debate Gets Its Icon: Mt. Kilimanjaro
By ANDREW C. REVKIN
Published: March 23, 2004
the storied mountain that rises nearly four miles above the shimmering
plains of Tanzania, is beginning to resemble the spotted owl — at least
in the way it has become a two-sided icon in an environmental debate.
owl first entered the spotlight 15 years ago, in fierce debate over
clear-cutting of ancient Pacific forests. Millions of acres were placed
off-limits to logging when the bird was listed as threatened under the
federal endangered-species law. Soon afterward, effigies of it began
showing up on the grilles of logging trucks.
majestic glacial cap of 11,000-year-old ice has long captured
imaginations the world over, so it was not surprising that
environmentalists focused their attention on it when scientists
reported in 2001 that glaciers around the world were retreating, partly
as a result of global warming caused by emissions of heat-trapping
"greenhouse" gases from smokestacks and tailpipes.
from Greenpeace, the environmental group, scaled the mountain in
November 2002 and held a news conference via satellite with reporters
at climate-treaty talks in Morocco. Last October, Senator John McCain,
the Arizona Republican who is co-author of a bill to curb greenhouse
gases, displayed before-and-after photographs of Kilimanjaro during a
Senate debate. A British scientist proposed hanging white fabric over
the glacier's ragged 10-story-tall edges to block sunlight and stem the
But now the pendulum has swung. This
month, the mountain was taken up as a symbol of eco-alarmism by a
cluster of scientists and anti-regulation groups. "Snow Fooling!: Mount
Kilimanjaro's glacier retreat is not related to global warming," read a
newsletter distributed on March 9 by the Greening Earth Society, a
private group financed by industries dealing in fossil fuels, the
dominant source of the heat-trapping gases. "Media and scientists blame
human activity, but a 120-year-old natural climate shift is the cause."
group cited a paper in the current International Journal of Climatology
asserting that Kilimanjaro's ice was shrinking because East Africa's
climate is drying, a process that began more than a century ago, long
before humans could have been an influence.
authors wrote that the dry weather both limited the snows that help
sustain tropical glaciers and, by reducing cloud cover, allowed more
solar energy to bathe the glacier. In dry, cold conditions, the ice
vaporized without melting first, a process called sublimation. There
was no evidence that rising temperatures had caused the melting, the
So what do these researchers
and the ones who first warned of glacial retreat have to say about the
clashing public portrayals of their work on Africa's highest peak?
unanimously, they agreed in interviews that the two depictions were
wrong, turning what is still a complicated scientific puzzle into a
The authors of the new
paper said their goal was to challenge what had become orthodoxy about
the mountain — that rising temperatures were eating away at the ice —
and to present an argument for a different mechanism. But their paper
was hardly conclusive, they said. It was mainly a call for more study.
are entirely against the black-and-white picture that says it is either
global warming or not global warming," said Prof. Georg Kaser, the
paper's lead author and a glaciologist at the Institute for Geography
of the University of Innsbruck, in Austria. "As a scientist I'm happy
it's more complex, because otherwise it's boring."
authors of the new study said they were particularly dismayed that the
industry-supported group had portrayed their paper as a definitive
refutation of the idea that melting from warming was involved.
have a mere 2.5 years of actual field measurements from Kilimanjaro
glaciers, unlike many other regions, so our understanding of their
relationship with climate and the volcano is just beginning to
develop," Dr. Douglas R. Hardy, a geologist at the University of
Massachusetts and an author of the paper, wrote by e-mail. "Using these
preliminary findings to refute or even question global warming borders
on the absurd."
In short, Kilimanjaro may be a
photogenic spokesmountain — no matter what the climatic agenda — but it
is far from ideal as a laboratory for detecting human-driven warming.
The debate over it obscures the nearly universal agreement among
glacier and climate experts that glaciers are retreating all over the
world, probably as a result of the greenhouse-gas buildup.
climate skeptics are making generalizations not only to the rest of the
tropics but the rest of the world," Dr. Hardy said. "And, in fact,
global warming may be part of the whole picture on Kilimanjaro, too."
experts in the Kilimanjaro debate accept three things: for more than a
century, its ice has been in a retreat that is almost assuredly
unstoppable and was not caused by humans; so far, there is scant data
on conditions there; and the main scientific question now is how, and
how much, climate shifts driven by heat-trapping emissions are
accelerating that trend.
Dr. Lonnie G.
Thompson, the Ohio State University glaciologist whose work first
focused attention on Kilimanjaro's fading ice, said he saw ample
evidence that melting was eating away at what remained.
specialty is extracting cylinders of layered, ancient ice from tropical
glaciers, and when his team drilled into one of the mountain's ice
fields in 2000, water flooded out of the hole. In the resulting cores,
shallow layers contained elongated bubbles — strong evidence of melting
and refreezing — while deeper layers had none.
jarring was the violent collapse of a 10-story-tall clifflike face of
one of Kilimanjaro's ice fields in January 2003, witnessed and
photographed by trekkers. The collapse sent a huge cascade of ice and
water gushing across the flanks of the ancient crater.
all suggests that what we are seeing at least in the last 20 years or
so is different," Dr. Thompson said. He believes the mountain may be
close to a threshold at which melting will become the dominant force
eroding the ice. "The balance of evidence says something bigger is
going on in the system," he said.
said that while the new paper selectively described evidence that
drying of African air was the culprit, it did not test that hypothesis.
the long-term drop in humidity is to blame, he went on. "But show me.
Give me something I can see. Otherwise you raise important issues that
need to be studied, and we need data on, but how do you know whether
Several independent glacier
experts who have followed the Kilimanjaro research said the new paper
and Dr. Thompson's earlier assertions about melting were probably both
right to some extent.
But some experts see
signs that something different has been happening in the region in
recent decades. A bit to the north, for example, on the flanks of Mount
Kenya, other scientists have been able to measure shifts in patterns of
ice loss that show solar radiation — the long-term influence on the ice
— is no longer dominating.
whose ice is mostly oriented toward the sun, Mount Kenya has ice in
shadow and sunlight. From 1899 to 1962, those ice fields more exposed
to direct solar radiation "wasted drastically" while those in narrow,
shaded grooves changed very little, said Dr. Stefan L. Hastenrath, a
professor emeritus at the University of Wisconsin, who is a
longstanding expert on African glaciology.
implied that changes in cloudiness and sunlight were the dominant force
determining the fate of ice. "But since the 1960's the mountain has
seen more even loss of ice in shaded and sun-exposed ice," he said.
editor of the Greening Earth newsletter, Dr. Patrick J. Michaels, a
University of Virginia climatologist, said he did not doubt that humans
were altering climate. He just feels, he says, there is no sign that
humans are pushing matters beyond the natural variability that already
exists — and already must be adapted to.
written a bunch of papers saying human beings are warming the planetary
surface temperature," he said. "It wouldn't surprise me that you'd see
midlatitude glacier recession. The question is, Why is this alarming?
Aside from the initial shock value of the notion that human beings can
change the climate, why is this such a story?"
Dr. Thompson sharply criticized the newsletter's interpretation of the
Kilimanjaro research. "These people get paid to muddy the waters," he
said. "At least we're going out and trying to get the data, which is
hard work. If you're going to sit in your office and send out your
e-mails with no basis, I'm sorry, but that just doesn't carry the day."
|Tim Davis/Photo Researchers Inc.
|Looming over the African landscape, Mount Kilimanjaro is the focus of a debate over whether its glacial retreat is related to global warming.|
|Douglas Hardy/University of Massachusetts
|Prof. Georg Kaser, left, and his team argue that the reasons the ice on Mount Kilimanjaro is melting are complex and should be studied further.|