Earth's Ice Melting Under Blanket of Greenhouse Gases

VIENNA, Austria, April 4, 2006 (ENS) - Large amounts of the greenhouse gas methane will be released into the atmosphere in the near future, according to a Dutch scientist speaking today at the European Geosciences Union (EGU 2006) meeting in Vienna. He said global warming could lead to melting of the arctic tundras, setting free large volumes of methane, which would in its turn increase global warming.

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Dr. Ko van Huissteden views the Siberian tundra from a small plane. (Photo courtesy Vrije Universiteit)
Methane is a much stronger greenhouse gas than carbon dioxide said Dr. J. (Ko) van Huissteden of Vrije Universiteit in Amsterdam. He explained that methane fluxes from the arctic permafrost areas attract scientific attention because the release of this powerful greenhouse gas may act as a positive feedback to climate warming.

Methane release is enhanced by increasing the metabolic activity of methane bacteria in warmer arctic soils, or by the release of methane from melting permafrost.

Van Huissteden's research in the tundra of northeast Siberian, conducted in cooperation with the Yakut institute of Biology, shows that the floodplains of arctic lowland rivers are major methane sources, where methane fluxes may be five times as high as in non-flooded tundra bogs.

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Spring melt leaves bare tundra in the Arctic. (Photo courtesy NOAA)
Moreover, he said, these fluxes are very sensitive to river discharge fluctuations and the incidence of river floods. Currently, both air temperature and river discharges are rising significantly in the arctic.

A panel of glaciologists at EGU 2006 said the consequence of global warming may be that, even in this century, coastal areas will be flooded worldwide.

The Greenland and West Antarctic Ice Sheets are losing ice at much faster rates than has been predicted, while the mechanisms causing this are not yet fully understood, they said Monday.

"There's no reason to run for the hills yet," says geoscientist Richard Alley of Pennsylvania State University. "However, observations show that Greenland and Antarctica are losing ice more rapidly than predicted by the models."

Eric Rignot, author of one of a number of recent papers in the journal "Science" about ice loss in Greenland, observed that over the last three years, outlet glaciers have been accelerating.

Rignot, a scientist with NASA's Jet Propulsion Laboratory in Pasadena, California said this has led to lowering of the ice surface of 100 meters (390 feet) in some places and serious ice loss, particularly in southern Greenland.

Even East Antarctica, traditionally viewed as a stable ice sheet, is losing ice, reports Isabella Velicogna of the University of Colorado. This is based on observations by the GRACE mission, calculating ice mass loss from satellite gravity measurements.

Jonathan Bamber with the Bristol Glaciology Centre, University of Bristol in the UK, said, "Changes like the ones we observe now have never been predicted."

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Jonathan Bamber is a professor of Physical Geography at the Bristol Glaciology Centre, University of Bristol. (Photo courtesy CPOM)
The changes in East Antarctica are worrying because, although they are relatively small, it means something is going on that we don't quite understand, said Bamber, who uses remote sensing data to describe and explain the dynamics of the Antarctic and Greenland ice sheets.

One possible mechanism, recent observations suggest, is sliding of fast flowing outlet glaciers on soft sediments. This could make these glaciers vulnerable to the present atmospheric warming.

Europe's Alps could lose three-quarters of their glaciers to climate change during the coming century, according to new research from Zurich's World Glacier Monitoring Service (WGMC) presented at the meeting.

"From 1850 to the 1970s, there is an average loss of 2.9 percent per decade," WGMC's Michael Zemp told EGU participants.

But that percentage of loss is accelerating rapidly. "From the 1970s until 2000 it is 8.2 percent per decade, and we see most of that increase since 1985," Zemp said.

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Gruben glacier (right) and Gruben rock glacier (left), Valais, Swiss Alps. (Photo courtesy NSIDC)
Alpine glaciers serve as freshwater reservoirs, storing winter snowfall and releasing it over the warm months for use in homes and on farms.

Without the glaciers, snowmelt would run off all at once in the spring, causing flooding and leaving little stored water for summer and fall.

An unexpected effect of increasing emissions of carbon dioxide (CO2) was reported Monday at EGU 2006. A panel of ocean experts said that by the end of this century, corals in large parts of the oceans will see their shells dissolving in sea water that is more and more acidic.

Cold water corals, species that have only been recently discovered, appear to be most threatened.

Panel members Jean-Pierre Gattuso, Joan Kleypas, Ulf Riebesell and James Orr said that the oceans have so far absorbed about a third of human-caused CO2 emissions, and that this uptake has serious consequences for ocean chemistry.

Adding CO2 to seawater reduces the pH level, which is referred to as ocean acidification. New findings indicate that changes in ocean chemistry due to acidification over the last 10 years are measurable even in the deep ocean.

Most research so far focused on the decline in calcification of corals, other reef organisms and some major planktonic groups of the open ocean due to this acidification. But less is known about the long-term effect of decalcification on the ecosystem. Research needs to be done on the ecosystemís response and adaptation to more acid oceans, the scientists said.

In fact, they said, virtually nothing is known about the biology of these animals including metabolism and reproduction. We know that larvae and eggs of many microplankton organisms are sensitive to even small increases in pH.

In Norwegian fjords experiments are conducted to simulate conditions of increasing CO2 concentrations. According to Joan Kleypas from the National Center for Atmospheric Research, Boulder, Colorado, we are only just becoming aware of the grave effects of increasing carbon dioxide on ocean organisms.

Kleypas said the only solution seems to be to decrease carbon dioxide emissions.