HOUSTON - A Texas-sized area of Antarctica is thinning and could cause the world's oceans to rise significantly in the long-term, polar ice experts said in wrapping up a three-day conference.[thanks for the tip, Woody]
"Surprisingly rapid changes" are occurring in Antarctica's Amundsen Sea Embayment, an ice drainage system that faces the southern Pacific Ocean, the experts said in a statement, adding that more study was needed to determine how fast it was melting and how much it could cause sea levels to rise.
The warning came Wednesday at the end of a conference of U.S. and European polar ice experts at the University of Texas in Austin...
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HOBART, Australia - The impact of global warming on the vast Southern Ocean around Antarctica is starting to pose a threat to ocean currents that distribute heat around the world, Australian scientists say, citing new deep-water data.
Melting ice-sheets and glaciers in Antarctica are releasing fresh water, interfering with the formation of dense "bottom water," which sinks 2-3 miles to the ocean floor and helps drive the world's ocean circulation system.
A slowdown in the system known as "overturning circulation" would affect the way the ocean, which absorbs 85 percent of atmospheric heat, carries heat around the globe...
"If the water gets fresh enough ... then it won't matter how much ice we form, we won't be able to make this water cold and salty enough to sink," said Steve Rintoul, a senior scientist at CSIRO, Australia's national science agency...
Water dense enough to sink to the ocean floor is formed in polar regions by surface water freezing, which concentrates salt in very cold water beneath the ice. The dense water then sinks.
Only a few places around Antarctica and in the northern Atlantic create water dense enough to sink to the ocean floor, making Antarctic "bottom water" crucial to global ocean currents.
But the freshening of Antarctic deep water was a sign that the "overturning circulation" system in the world's oceans might be slowing down, Rintoul said, and similar trends are occurring in the North Atlantic...
Rintoul, who has led teams tracking water density around the Antarctic through decades of readings, said his findings add to concerns about a "strangling" of the Southern Ocean by greenhouse gases and global warming.
Australian scientists warned last month that waters surrounding Antarctica were also becoming more acidic as they absorbed more carbon dioxide produced by nations burning fossil fuels.
Acidification of the ocean is affecting the ability of plankton — microscopic marine plants, animals and bacteria — to absorb carbon dioxide, reducing the ocean's ability to sink greenhouse gases to the bottom of the sea.
Rintoul said that global warming was also changing wind patterns in the Antarctic region, drawing them south away from the Australian mainland and causing declining rainfall in western and possibly eastern coastal areas.
This was contributing to drought in Australia, one of the world's top agricultural producers, he said.
And from behind Teh New York Pravda's Select firewall:
A House committee released documents Monday that showed hundreds of instances in which a White House official who was previously an oil industry lobbyist edited government climate reports to play up uncertainty of a human role in global warming or play down evidence of such a role.
In a hearing of the House Committee on Oversight and Government Reform, the official, Philip A. Cooney, who left government in 2005, defended the changes he had made in government reports over several years. Mr. Cooney said the editing was part of the normal White House review process and reflected findings in a climate report written for President Bush by the National Academy of Sciences in 2001.
They were the first public statements on the issue by Mr. Cooney, the former chief of staff of the White House Council on Environmental Quality. Before joining the White House, he was the ''climate team leader'' for the American Petroleum Institute, the main industry lobby.
He was hired by Exxon Mobil after resigning in 2005 following reports on the editing in The New York Times. The White House said his resignation was not related to the disclosures...
And so it goes. How much ice melted in Antartica this winter? The data are there, even if they're not being released.
...Just a few years ago, the world's climate scientists predicted that Greenland wouldn't have much impact at all on sea level in the coming decades. But recent measurements show that Greenland's ice cap is melting much faster than expected.
These new data come from the NASA/German Aerospace Center's Gravity Recovery and Climate Experiment (Grace). Launched in March 2002, the twin Grace satellites circle the globe using gravity to map changes in Earth's mass 500 kilometers (310 miles) below. They are providing a unique way to monitor and understand Earth's great ice sheets and glaciers.
Grace measurements have revealed that in just four years, from 2002 to 2006, Greenland lost between 150 and 250 cubic kilometers (36 to 60 cubic miles) of ice per year. One cubic kilometer is equal to about 264 billion gallons of water. That's enough melting ice to account for an increase in global sea level of as much as 0.5 millimeters (0.019 inches) per year, according to Isabella Velicogna and John Wahr of the University of Colorado, Boulder. They published their results in the scientific journal Nature last fall. Since global sea level has risen an average of three millimeters (0.1 inch) per year since 1993, Greenland's rapidly increasing contribution can't be overlooked.
"Before Grace, the change of Greenland's ice sheet was inferred by a combination of more regional radar and altimeter studies pieced together over many years, but Grace can measure changes in the weight of the ice directly and cover the entire ice sheet of Greenland every month," says Michael Watkins, Grace project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. However, as anyone who has ever been concerned about his or her weight knows, a number on a scale is just the beginning. In the five years that Grace has been flying, scientists have found ways to make the most of this new set of observations.
"Grace has a big footprint," says Watkins. "We can locate regions of greatest loss, but we can't see individual glaciers." However, Grace's spatial resolution is continually improving. In the most recent studies, he says, Grace has observed large ice losses in the southeast of Greenland, while other areas, such as the west coast, have shown losses as well...
As Grace celebrates its fifth birthday and begins its extended mission, "we're getting the picture into better focus," says Watkins, "and we're going to have a new wave of discoveries. Improving the post-glacial rebound model is going to help, especially in Antarctica, where post-glacial rebound has a big effect on the gravity signal. We're also going to be able to pinpoint areas of loss and better understand how the losses change from one particular year to the next. This will tell us more about the types and mechanisms of ice mass loss so we can make better predictions in the future."
While Grace provides a new and independent way to study Earth's ice sheets, it will take a combination of different tools, including laser altimeters, radar, and field studies, to sort out more clearly what's happening. "All technologies have different strengths and weaknesses," says Watkins. "Grace is the new piece. It shows us the big picture, while other measurements look at a smaller scale. We need to use them all together."
"We have to pay attention," Velicogna adds. "These ice sheets are changing much faster than we were expecting. Observations are the most powerful tool we have to know what is going on, especially when the changes - and what's causing them - are not obvious."
Well, they would be obvious, if the NOAA scientists could speak without a Commissar listening for Party purity and trying to axe the jobs of those stepping outside the Party line.
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