It is held in place by a 25-mile long strip of ice that has shrunk to about 500m wide at its narrowest point and could collapse at any time.

Glaciologist David Vaughan of the British Antarctic Survey said it is miraculous the shelf is still there.

The Wilkins once covered 6,178 sq miles but lost a third of its area and is now the size of Jamaica, but once the ice bridge collapses, sea currents are likely to sweep away much of what is left.

Nine other shelves have collapsed or receded around the Antarctic peninsula in the past 50 years - often abruptly such as the Larsen A in 1995 or the Larsen B in 2002.

The change is widely blamed on heat-trapping gases from burning fossil fuels.

In total, about 15,500 sq miles of ice shelves have been lost, changing the maps of Antarctica in one of the most dramatic signs of climate change.

Ocean sediments indicate that some shelves had been in place for at least 10,000 years.

 

 

 

 

 

 

 

More than 2 trillion tons of land ice in Greenland, Antarctica and Alaska have melted since 2003, according to new NASA satellite data that show the latest signs of what scientists say is global warming.

More than half of the loss of landlocked ice in the past five years has occurred in Greenland, based on measurements of ice weight by NASA's GRACE satellite, said NASA geophysicist Scott Luthcke. The water melting from Greenland in the past five years would fill up about 11 Chesapeake Bays, he said, and the Greenland melt seems to be accelerating.

NASA scientists planned to present their findings Thursday at the American Geophysical Union conference in San Francisco. Luthcke said Greenland figures for the summer of 2008 aren't complete yet, but this year's ice loss, while still significant, won't be as severe as 2007.

The news was better for Alaska. After a precipitous drop in 2005, land ice increased slightly in 2008 because of large winter snowfalls, Luthcke said. Since 2003, when the NASA satellite started taking measurements, Alaska has lost 400 billion tons of land ice.

In assessing climate change, scientists generally look at several years to determine the overall trend.

Melting of land ice, unlike sea ice, increases sea levels very slightly. In the 1990s, Greenland didn't add to world sea level rise; now that island is adding about half a millimeter of sea level rise a year, NASA ice scientist Jay Zwally said in a telephone interview from the conference.

Between Greenland, Antarctica and Alaska, melting land ice has raised global sea levels about one-fifth of an inch in the past five years, Luthcke said. Sea levels also rise from water expanding as it warms.

Other research, being presented this week at the geophysical meeting point to more melting concerns from global warming, especially with sea ice.

"It's not getting better; it's continuing to show strong signs of warming and amplification," Zwally said. "There's no reversal taking place."

Scientists studying sea ice will announce that parts of the Arctic north of Alaska were 9 to 10 degrees warmer this past fall, a strong early indication of what researchers call the Arctic amplification effect. That's when the Arctic warms faster than predicted, and warming there is accelerating faster than elsewhere on the globe.

As sea ice melts, the Arctic waters absorb more heat in the summer, having lost the reflective powers of vast packs of white ice. That absorbed heat is released into the air in the fall. That has led to autumn temperatures in the last several years that are six to 10 degrees warmer than they were in the 1980s, said research scientist Julienne Stroeve at the National Snow and Ice Data Center in Boulder, Colo.

That's a strong and early impact of global warming, she said.

"The pace of change is starting to outstrip our ability to keep up with it, in terms of our understanding of it," said Mark Serreze, senior scientist at the National Snow and Ice Data Center and a co-author of the Arctic amplification study.

Two other studies coming out at the conference assess how Arctic thawing is releasing methane — the second most potent greenhouse gas. One study shows that the loss of sea ice warms the water, which warms the permafrost on nearby land in Alaska, thus producing methane, Stroeve says.

A second study suggests even larger amounts of frozen methane are trapped in lakebeds and sea bottoms around Siberia and they are starting to bubble to the surface in some spots in alarming amounts, said Igor Semiletov, a professor at the University of Alaska in Fairbanks. In late summer, Semiletov found methane bubbling up from parts of the East Siberian Sea and Laptev Sea at levels that were 10 times higher than they were in the mid-1990s, he said based on a study this summer.

The amounts of methane in the region could dramatically increase global warming if they get released, he said.

That, Semiletov said, "should alarm people."

 

article provided by: http://www.enn.com/ecosystems/article/38992 and http://www.stopglobalwarming.org/sgw_read.asp?id=5064512162008

 

 

 

 

 

 

San Francisco-- The United States could suffer the effects of abrupt climate changes

within decades—sooner than some previously thought--says a new government report. It contends that seas could rise rapidly if melting of polar ice continues to outrun recent projections, and that an ongoing drought in the U.S. west could be the start of permanent drying for the region. Commissioned by the U.S. Climate Change Science Program, the report was authored by experts from the U.S. Geological Survey, Columbia University's Lamont-Doherty Earth Observatory and other leading institutions. It was released at this week's meeting of the American Geophysical Union.

Many scientists are now raising the possibility that abrupt, catastrophic switches in natural systems may punctuate the steady rise in global temperatures now underway. However, the likelihood and timing of such "tipping points," where large systems move into radically new states, has been controversial. The new report synthesizes the latest published evidence on four specific threats for the 21st century. It uses studies not available to the Intergovernmental Panel on Climate Change (IPCC), whose widely cited 2007 report explored similar questions. "This is the most up to date, as it includes research that came out after IPCC assembled its data," said Edward Cook, a climatologist at Lamont-Doherty and a lead author of the new study.

The researchers say the IPCC's maximum estimate of two feet of sea level rise by 2100 may be exceeded, because new data shows that melting of polar ice sheets is accelerating. Among other things, there is now good evidence that the Antarctic ice cap is losing overall mass. At the time of the IPCC report, scientists were uncertain whether collapses of ice shelves into the ocean off the western Antarctica were being offset by snow accumulation in the continent's interior. But one coauthor, remote-sensing specialist Eric Rignot of the Jet Propulsion Laboratory, told a press conference at the meeting: "There is a new consensus that Antarctica is losing mass." Seaward flow of ice from Greenland is also accelerating. However, projections of how far sea levels might rise are "highly uncertain," says the report, as researchers cannot say whether such losses will continue at the same rates.

In the interior United States, a widespread drought that began in the Southwest about 6 years ago could be the leading edge of a new climate regime for a wider region. Cook, who heads Lamont's Tree Ring Lab, says that periodic droughts over the past 1,000 years have been driven by natural cycles in air circulation, and that these cycles appear to be made more intense and persistent by warming. Among the new research cited is a 2007 Science paper by Lamont climate modeler Richard Seager, showing how changes in temperature over the Pacific have driven large-scale droughts across western North America. "We have no smoking gun saying that humans are causing the current changes. But the past is a cautionary tale," Cook told the press conference. "What this tells us is that the system has the ability to lock into periods of profound, long-lasting aridity. And there is the suggestion that these changes are related to warmer climate." Cook added: "If the system tips over, that would have catastrophic effects no human activities and populations over wide areas."

The panel said two other systemic changes seem less imminent, but are still of concern. Vast quantities of methane, a potent greenhouse gas, have long been locked up in ocean sediments, wetlands and permafrost. These could be destabilized by climate change, leading to blowouts of gas, and thus even more abrupt temperature shifts. The panel said blowouts appear unlikely in the next 100 years—but that steady emissions could double, especially in the north, as land and water warm up. The panel also looked at the continuous circulation of the Atlantic Ocean, which sends warm water northward and cold water southward, controlling the climate of western Europe and beyond. Some scientists say this circulation could collapse if enough northern ice melts and dilutes the salty water. The panel found this scenario unlikely in the short term, but warned that the circulation's strength might decline 25% to 30% by 2100.

"Abrupt climate change presents potential risks for society that are poorly understood," the researchers write. [There is an] urgent need for committed and sustained monitoring of those components [that] are particularly vulnerable."

The report, Synthesis and Assessment Product 3.4: Abrupt Climate Change, is at: http://www.climatescience.gov/Library/sap/sap3-4/final-report/default.htm.

The Earth Institute at Columbia University mobilizes the sciences, education and public policy to achieve a sustainable earth. Through interdisciplinary research among more than 500 scientists in diverse fields, the Institute is adding to the knowledge necessary for addressing the challenges of the 21st century and beyond. www.earth.columbia.edu

Lamont-Doherty Earth Observatory, a member of The Earth Institute, is one of the world's leading research centers seeking fundamental knowledge about the origin, evolution and future of the natural world. More than 300 research scientists study the planet from its deepest interior to the outer reaches of its atmosphere, on every continent and in every ocean--from global climate change to earthquakes, volcanoes, nonrenewable resources, environmental hazards and beyond. www.ldeo.columbia.edu

 

 

(source of article: http://www.enn.com/top_stories/article/38913)

 

 

  The world is on the brink of a massive extinction event, according to the United Nations. Rapid releases of greenhouse gas emissions are changing habitats at a rate faster than many of the world's species can tolerate.

"Indeed the world is currently facing a sixth wave of extinctions, mainly as a result of human impacts," said Achim Steiner, executive director of the U.N. Environment Programme in a statement. A study earlier this year in the Proceedings of the National Academies of Science said the current extinction period, known as the Holocene extinction event, may be the greatest event in the Earth's history and the first due to human actions. Unlike previous events, however, extinctions are happening over the course of decades rather than centuries. Recent studies suggest that a quarter of the world's species may go extinct by 2050.

The UN warning accompanies an increasingly frequent round of sobering news about ecosystem failures.

The latest global coral reef assessment estimates that 19 percent of the world's coral reefs are dead. Their major threats include warming sea-surface temperatures and expanding seawater acidification.

Zooxanthellae, the tiny organisms that give coral reefs their vibrant colors, are emigrating from their hosts in massive numbers as oceans heat up, killing themselves and the coral they leave behind - a process known as coral bleaching.

The report, released by the Global Coral Reef Monitoring Network Wednesday at the international climate change negotiations in Poznań, Poland, predicts that many of the remaining reefs may disappear within the next 40 years if current emission trends continue.

"If nothing is done to substantially cut emissions, we could effectively lose coral reefs as we know them, with major coral extinctions," said Clive Wilkinson, the network's coordinator, in a press release.

Overfishing, pollution, and invasive species continue to be risks as well, according to the International Union for the Conservation of Nature(IUCN).

The IUCN declared in October that 38 percent of the 44,838 species it studied across the world are threatened with extinction. Its Red List of Threatened Species considers 22 percent of the world's mammals, 31 percent of amphibians, and 14 percent of birds threatened or extinct.

Steiner's warnings of mass extinction came last week as the U.N. Convention on the Conservation of Migratory Species of Wild Animals added 21 migratory species to its protection list. Migratory species are among the most at-risk to climate change, according to a UNEP report released last year [PDF].

To its list of protected animals, which include the cheetah and Egyptian vulture, the convention added six dolphin species.  Nearly one-quarter of the world's dolphin species are threatened with extinction, mostly due to habitat loss and live capture, according to IUCN.

The demise of coral reefs, however, affects the entire ocean ecosystem - a quarter of all marine fish species reside in the reefs, according to The Nature Conservancy. In addition, IUCN estimates that 500 million people depend on coral reefs for their livelihoods.

The coral reef assessment found that 45 percent of the world's reefs are healthy - providing hope that some species may be able to endure the changes expected from global warming. Marine biologists are now attempting to understand how certain coral reef species can survive warmer, more acidic ocean waters when others are less fortunate.

Ben Block is a staff writer with the Worldwatch Institute. He can be reached at bblock@worldwatch.org.

 

to view the article, go to: http://www.enn.com/top_stories/article/38850

 

 

Operation: World Wide has received a new name.

Now I welcome you to-- OPERATION: INCREASE THE PEACE!

 

This blog is dedicated to increasing peace amongst people, animal rights and welfare, endangered species, love and harmony, human rights, and so much more.

Please feel free to check out the links to your left, leave a tag or comment. After the holidays, I will begin working on posting more here again.

 

Also feel free to link to this blog so that you can continue to drop by and visit.

 

Thank you and lots of love and peace-

 

Mystic Lady (http://mystic_lady.bravejournal.com)