Global Rockhound Community Enviromental News
Issue 04: April 2007: Editor Sally Taylor: www.rockhoundstation1.com
In this issue: Global warming:- The Aral sea:- The melting of Greenland (Image article):-
RHS1 Global Rockhound Community Enviromental News,Monitoring, earthquakes, global warming, climate change, hurricanes and tornados, bio-diversity, keeping an eye on our fast changing planet. Climate change,global warming,earthquake, earthwatch,Chandler wobble, Chandler's wobble,rockhound world center,
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RHS1 EARTHWATCH
The colder the Air the Faster it warms
During the past two decades, temperatures have risen faster in the Arctic than anywhere else on the planet. Josefino Comiso, research scientist at NASA Goddard Space Flight Center, found that temperatures over Arctic summer sea ice increased 1.22 degC per decade beginning in 1980. The Arctic as a whole warmed eight times faster over the past two decades than over the past 100 years.
Air temperatures in the Antarctic Peninsula region have risen by over 2.5deg: C in the last 50 years, about 5 times faster than the global mean rate.
In recent decades both Polar Regions have shown very contrasting patterns of change at the surface, with the Arctic warming markedly, while there has been little change in the Antarctic outside of the Antarctic Peninsula region. Changes above the surface have not been investigated previously.
British Antarctic Survey.
Alaska, Northern Canada, Greenland, Siberia,...
(Quote below from a letter to the Subcommittee on National
Economic
Growth, Natural Resources and Regulatory Affairs,
U.S. House of Representatives,)
"Recently published research (Michaels et al., 1999; Michaels et al., accepted) shows that over three quarters of the winter warming is confined to this very cold air. When we compare the average postwar warming in the statistical gridcells that comprise these airmasses to those that don't, the result is truly stunning. The coldest air is warming up a rate 10 times larger than the remainder of the hemisphere; That research also proves that the warming is largely confined to the cold air masses, and that the more severely cold they are, the more they warm."
Patrick J. Michaels
Professor of Environmental Sciences
University of Virginia,
and Senior Fellow in
Environmental Studies at Cato Institute
October 6, 1999
Click here to Read this letter
Greenland's flag
"The ice sheet covering Earth's largest island of Greenland has an area of 1 833 900 square kilometres and an average thickness of 2.3 kilometres. It is the second largest concentration of frozen freshwater on Earth and if it were to melt completely global sea level would increase by up to seven metres / 22 feet"...E.S.A.
Longyearbyen, Greenland in 2002 (bottom). A similar image taken in 1928 (top).
The ridge of Kongsbreen, Greenland in 2002 (bottom). A similar image taken in 1928 (top).
The receding glacier "Blomstrandbreen" Greenland in 2002 (bottom). A similar image taken in 1928 (top).
A panoramic view of Longyearbyen, Greenland taken in 2002 (bottom). A similar image taken in 1928 (top).
Lakes are begining to form on the iceshield: Greenland.
Ice melt 2005: Greenland.
How fast is the ice Melting?
"The Helheim Glacier now appears to be moving
about half a football field every day."...NASA.
The alarming retreat of the Kangerdlugssuaq Glacier suggests that the entire Greenland ice sheet may be melting far more rapidly than previously believed. All current scientific forecasts for global warming had assumed slower rates of melting. This new evidence suggests that the threat of global warming is much greater and more urgent than previously believed.
The Greenland ice sheet is three [km] thick and broad enough to blanket an area the size of Mexico. The ice is so massive that its weight presses the bedrock of Greenland below sea level, so all-concealing that not until recently did scientists discover that Greenland actually might be three islands.
It is thought that before the Ice Age Greenland had mountainous edges, and a lowland (and probably very dry) center which drained to the sea by one big river flowing out westwards past where Disko is now.
There is concern about sea level rise caused by ice loss (melt and glaciers falling into the sea) on Greenland. Between 1997 and 2003 ice loss was 80+/-12 km cubed/yr, compared to about 60 km cubed/yr for 1993/4-1998/9. Half of the increase was from higher summer melting, with the rest caused by velocities of some glaciers exceeding those needed to balance upstream snow accumulation (Krabill et al., L24402, GRL 2004). A complete loss of ice on Greenland would cause a sea level rise of as much as 6.40 meters.
Researchers at NASA's Jet Propulsion Laboratory and the University of Kansas reported in February 2006 that the glaciers are melting twice as fast as they were five years ago. By 2005, Greenland was beginning to lose more ice volume than anyone expected an annual loss of up to 52 cubic miles per year (216 km cubed/yr), according to more recent satellite gravity measurements released by JPL.
Between 1991 and 2006, monitoring of the weather at one location (Swiss Camp) found that the average winter temperature had risen almost 10 degrees fahrenheit.
Since 2002, Greenland's three largest outlet glaciers have started moving faster, satellite data show. On the eastern edge of Greenland, the Kangerlussuaq Glacier, like the Jakobshavn Isbrae, has surged, doubling its pace. To the west, the Helheim Glacier now appears to be moving about half a football field every day. The accelerating ice flow has been accompanied by a dramatic increase in seismic activity. In March 2006, researchers at Harvard University and the Lamont-Doherty Earth Observatory at Columbia University reported that the glaciers now generate swarms of earthquakes up to magnitude 5.0.
The retreat of Greenland's ice is revealing islands that were thought to be part of the mainland. In September 2005 Dennis Schmitt discovered an island 400 miles north of the Arctic Circle in eastern Greenland which he named Uunartoq Qeqertoq, Inuit for "warming island".
What's happening?
After Antarctica, Greenland's ice cap contains the second largest mass of frozen freshwater in the world. This new research indicates enough ice loss to cause a measurable rise in sea levels. Quantified conservatively, the study indicates a net loss of roughly 51 cubic kilometers of ice per year from the entirety of the Greenland ice sheet. That's enough to raise the average sea level worldwide about .13 millimeters per year. While that might not sound like much, consider that in the space of only a single lifetime, it's nearly 1 centimeter of rise, and that's only if we assume the rate of increase remains the same.
Experts know there have been significant changes to the planet's ice caps and oceans in geologically recent history. Since the last interglacial period (The Eemian) roughly 110,000 to 130,000 years ago, the sea level has risen approximately four meters. What's important is a better understanding of how human and natural processes are conjoined to affect changes in the important ice caps of the world we know today.
Based on new research using NASA's airborne laser altimeter, scientists have identified pronounced thinning of Greenland's ice cap. Notice how the thinning is most severe along the coasts, while the center of the landmass appears to thicken slightly., blues indicate areas where the loss of ice is greatest, and yellows indicate regions that are apparently thickening. Gray areas indicate no significant change in ice thickness.
credit for this images to:
NASA/Goddard Space Flight Center
Scientific Visualization Studio
Television Production NASA-TV/GSFC
The study of Greenland's ice is another example of how a somewhat localized phenomenon is providing insight to climate systems that relate to the entire planet. Only with continued observations will more comprehensive understanding of the trends there be determined.
The study of ice in Greenland has significance for the rest of our planet. It's one-seventh the size of Antarctica, but because it protrudes into more temperate latitudes, it may be a better indicator of climate change than the larger landmass found in the south.
Global ice cover acts as the planet's thermostat, regulating temperature by reflecting sunlight back into space. It also holds most of the Earth's fresh water (water that would otherwise swamp what are now coastal lowlands around the world).
Climate change presents challenges to researchers because it often concerns combinations of many interrelated processes. But Greenland may be for climatologists what canaries used to be for miners: an early warning monitor.
Greenland's coat of arms
Images: Courtesy of Greenpeace: Nasa:
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