Greenland melt 'speeding up'

[Pchan 5,162]

http://news.bbc.co.uk/2/hi/science/nature/4783199.stm

The meltdown of Greenland's ice sheet is speeding up, satellite measurements show. Data from a US space agency (Nasa) satellite show that the melting rate has accelerated since 2004.

If the ice cap were to completely disappear, global sea levels would rise by 6.5m (21 feet).

Most of the ice is being lost from eastern Greenland, a US team writes in Science journal.

Jianli Chen of the University of Texas at Austin and colleagues studied monthly changes in the Earth's gravity between April 2002 and November 2005.

These measurements came from the US space agency's Grace (Gravity Recovery and Climate Experiment) satellite, launched in 2002.

From these data, they were able to estimate changes in the mass of Greenland's ice sheet.

A number of factors contribute to fluctuations in the Earth's gravity field.

But once the influence of the atmosphere and the oceans is removed, the variations mostly reflect changes in the mass of ice sheets and of water stored in the ground.

Estimated monthly changes in the mass of Greenland's ice sheet suggest it is melting at a rate of about 239 cubic kilometres (57.3 cubic miles) per year.

This figure is about three times higher than an earlier estimate of the mass loss from Greenland made using the first two years of Grace measurements.

Satellite data

Dr Chen and colleagues partly attribute this to increased melting in the past one-and-a-half years and partly to better processing of the data.

"Acceleration of mass loss over Greenland, if confirmed, would be consistent with proposed increased global warming in recent years," the authors wrote in Science.

This would amount to a contribution to global sea level rise from Greenland of about half a millimetre (0.02 inches) each year.

The group's findings agree remarkably well with a study released earlier this year that used data from other satellites to estimate mass changes in the Greenland ice.

Grace also appears to have detected a loss of ice from Arctic glaciers that were omitted from this study and are separate from the main Greenland ice sheet.

[Ladywriter 7,783]

*sigh*

[DeathscytheX 9,732]

Actually there probably wouldn't be any major change in sea level because the ice cap wont be allowed to melt completely. All that ice melting over time will dump gallons of fresh water into the altantic conveyor completely screwing up the warm water current. This would result in a miniture ice age. This has already been recorded once in history back near colonial america time. One year they didnt even have summer, it was winter all year. The so called "mini ice age" lasted about 100 years.

Although it wouldnt change the landscape the results would still be disasterous on a economic and agracultural scale.

Edit: A program on this very thing is on History Channel right now.

[Ladywriter 7,783]

According to a study by University of Texas scientists Jianli Chen, Byron Tapley and Clark Wilson, published in the on-line edition of the journal Science, the ice layer on Greenland is melting at a rate three times faster than it was five years ago. The team has based its finding on the melting trend on observations for over a decade while monitoring a satellite mission that measures changes in the earth's gravity over Greenland as the ice layer there melts and the water flows into the Arctic ocean.

Chen said the team has been watching the melting during a relatively short period, but it has provided the strongest evidence of it and in the near future the pace of melting will accelerate even more.

Another team of scientists, studying the trend of melting ice in Antarctica, based on data provided by the same satellites, said the Antarctican melting too is leading to the rise in sea level.

According to scientists, Greenland is the largest reservoir of fresh water on earth next to Antarctica and it holds about 10 per cent of the world's supply. The increasing flow of fresh water from the melting glaciers on Greenland's eastern coast has already started changing the composition of oceanic currents flowing in Northwestern Europe.

Hypothetically, if the Greenland ice cover melts down completely -- which is unlikely to happen -- the world's sea level would rise by an average of 6.5 meters, or about 21 feet, which is more than sufficient to down all the world's low-lying islands and even countries like Holland.

Chen and his team say the melting of Greenland's ice cover is already raising global sea levels by six-tenths of a millimeter each year, while the scientists who studied the Antarctic ice melting say it is adding up to four-tenths of a millimeter of fresh water to sea levels each year.

http://www.earthtimes.org/articles/show/8083.html

[Pchan 5,162]

http://news.bbc.co.uk/2/hi/science/nature/5303574.stm

One of America's top scientists has said that the world has already entered a state of dangerous climate change. In his first broadcast interview as president of the American Association for the Advancement of Science, John Holdren told the BBC that the climate was changing much faster than predicted.

"We are not talking anymore about what climate models say might happen in the future.

"We are experiencing dangerous human disruption of the global climate and we're going to experience more," Professor Holdren said.

He emphasised the seriousness of the melting Greenland ice cap, saying that without drastic action the world would experience more heatwaves, wild fires and floods.

He added that if the current pace of change continued, a catastrophic sea level rise of 4m (13ft) this century was within the realm of possibility; much higher than previous forecasts.

To put this in perspective, Professor Holdren pointed out that the melting of the Greenland ice cap, alone, could increase world-wide sea levels by 7m (23ft), swamping many cities.

Safe limits

He blamed President Bush not only for refusing to cut emissions, but also for failing to live up to his rhetoric on harnessing technology to tackle climate change.

"We are not starting to address climate change with the technology we have in hand, and we are not accelerating our investment in energy technology research and development," Professor Holdren observed.

He said research undertaken by Harvard University revealed that US government spending on energy research had not increased since 2001. In order to make any progress, funding for climate technology needed to multiply by three or four times, Professor Holdren warned.

Last year, the UK's Prime Minister, Tony Blair, held a science conference to determine the threshold of dangerous climate change. Delegates concluded that to be relatively certain of keeping the rise below 2C (3.6F), CO2 levels in the atmosphere should not exceed 400 parts per million (ppm) and the highest prudent limit should be 450 ppm.

In October, at an international conference in Mexico, UK environment and energy ministers will try to persuade colleagues from the top 20 most polluting nations to agree on a CO2 stabilisation level.

Professor Holdren expressed doubt that progress could be achieved because if the US administration agreed that there was a need to limit CO2, this would inevitably lead to mandatory caps. President Bush has already rejected that option.

For more than a year, the BBC has invited the US government to give its view on safe levels of CO2. Our request is repeatedly passed between the White House office of the Council on Environmental Quality and the office of the US chief scientist.

To date, we have received no response to questions on this issue that Tony Blair calls the most important in the world. Professor Holdren called on the US Government to back the UK position.

John Holdren, in addition to his presidency of the AAAS, is a director of the Woods Hole Research Center, and Teresa and John Heinz Professor of Environmental Policy at Harvard University.

[Ladywriter 7,783]

yarg I can't bitch about ice enough can I *sigh*

[Ladywriter 7,783]

NASA: Greenland ice sheet shrinking

POSTED: 10:29 a.m. EDT, October 20, 2006

WASHINGTON (Reuters) -- The vast sheet of ice that covers Greenland is shrinking fast, but still not as fast as previous research indicated, NASA scientists said Thursday.

Greenland's low coastal regions lost 155 gigatons (41 cubic miles) of ice each year between 2003 and 2005 from excess melting and icebergs, the scientists said in a statement.

The high-elevation interior gained 54 gigatons (14 cubic miles) annually from excess snowfall, they said.

This is a change from the 1990s, when ice gains approximately equaled losses, said Scott Luthcke of NASA's Planetary Geodynamics Laboratory outside Washington.

"That situation has now changed significantly, with an annual net loss of ice equal to nearly six years of average water flow from the Colorado River," Luthcke said.

Luthcke and his team reported their findings in Science Express, the advance edition of the journal Science.

The ice mass loss in this study is less than half that reported in other recent research, NASA said in a statement, but it still shows that Greenland is losing 20 percent more mass than it gets in new snowfall each year.

The Greenland ice sheet is considered an early indicator of the consequences of global warming, so even a slower ice melt there raises concerns.

"This is a very large change in a very short time," said Jay Zwally, a co-author of the study. "In the 1990s, the ice sheet was growing inland and shrinking significantly at the edges, which is what climate models predicted as a result of global warming.

"Now the processes of mass loss are clearly beginning to dominate the inland growth, and we are only in the early stages of the climate warming predicted for this century," Zwally said.

http://www.cnn.com/2006/TECH/science/10/20/environment.greenland.reut/index.html

[Pchan 5,162]

20 % is no joke