Soot Pollution Melting Glaciers
Soot Pollution Melting Glaciers
These glaciers are a sign of what is going into your lungs. If we
replaced all the world's coal electric power plants with nukes we'd
breathe cleaner air and the glaciers wouldn't lose so much ice.
WASHINGTON – Black soot deposited on Tibetan glaciers has
contributed significantly to the retreat of the world's largest non-
polar ice masses, according to new research by scientists from NASA
and the Chinese Academy of Sciences. Soot absorbs incoming solar
radiation and can speed glacial melting when deposited on snow in
sufficient quantities.
Temperatures on the Tibetan Plateau -- sometimes called Earth's
"third pole" -- have warmed by 0.3°C (0.5°F) per decade over the
past 30 years, about twice the rate of observed global temperature
increases. New field research and ongoing quantitative modeling
suggests that soot's warming influence on Tibetan glaciers could
rival that of greenhouse gases.
"Tibet's glaciers are retreating at an alarming rate," said
James Hansen, coauthor of the study and director of NASA's Goddard
Institute for Space Studies (GISS) in New York City. "Black soot is
probably responsible for as much as half of the glacial melt, and
greenhouse gases are responsible for the rest."
"During the last 20 years, the black soot concentration has
increased two- to three-fold relative to its concentration in
1975," said Junji Cao, a researcher from the Chinese Academy of
Sciences in Beijing and a coauthor of the paper.
The study was published December 7th in the Proceedings of the
National Academy of Sciences.
"Fifty percent of the glaciers were retreating from 1950 to
1980 in the Tibetan region; that rose to 95 percent in the early
21st century," said Tandong Yao, director of the Chinese Academy's
Institute of Tibetan Plateau Research. Some glaciers are retreating
so quickly that they could disappear by mid-century if current
trends continue, the researchers suggest.
See this post over at Naked Capitalism (which includes quotes by
James Hansen about soot pollution) about why soot pollution
reduction should be a priority. Why not cut soot pollution ahead of
carbon dioxide emissions. The move will certainly improve human
health, reduce glacier melting (and therefore improve water
supplies in the summer), and will have a cooling effect. Landscape
darkened by soot absorbs more light and therefore heats up.
Soot in India draws more moisture and heat northward to do even
more to melt the glaciers. Obviously India also should replace its
coal electric plants with nuclear power plants.
The thick soot and dust layer absorbs solar radiation, and
heats up the air around the Himalayan foothills. The warm, rising
air enhances the seasonal northward flow of humid monsoon winds,
forcing moisture and hot air up the slopes of the Himalayas.
As the aerosol particles rise on the warm, convecting air, they
produce more rain over northern India and the Himalayan foothill,
which further warms the atmosphere and fuels a "heat pump" that
draws yet more warm air to the region.
"The phenomenon changes the timing and intensity of the
monsoon, effectively transferring heat from the low-lying lands
over the subcontinent to the atmosphere over the Tibetan Plateau,
which in turn warms the high-altitude land surface and hastens
glacial retreat," Lau said. His modeling shows that aerosols --
particularly black carbon and dust -- likely cause as much of the
glacial retreat in the region as greenhouse gases via this "heat
pump" effect.
Many rivers will be harmed by the loss of meltwater during the
drier periods. Rising populations will of course make this problem
much worse.
A unique landscape plays supporting actor in the melting drama.
The Himalayas, which dominate the plateau region, are the source of
meltwater for many of Asia's most important rivers—the Ganges and
Indus in India, the Brahmaputra in Bangladesh, the Salween through
China, Thailand and Burma, the Mekong across Laos, Cambodia and
Vietnam, and the Yellow and Yangtze rivers in China. When fossil
fuels are burned without enough oxygen to complete combustion, one
of the byproducts is black carbon, an aerosol that absorbs solar
radiation (Most classes of aerosols typically reflect incoming
sunlight, causing a cooling effect). Rising populations in Asia,
industrial and agricultural burning, and vehicle exhaust have
thickened concentrations of black carbon in the air.
Update: One quarter of the soot could be removed for just $15
billion.
But one simple measure could slow warming in some of Earth’s
most sensitive regions, effective immediately — and it would cost
just $15 billion.
That’s a rough price tag for providing clean stoves to the 500
million households that use open fires, fed by wood and animal dung
and coal, to heat their homes and cook.
This would improve the health of billions of people.
By Randall Parker at 2009 December 16 06:07 PM Pollution Trends
