"Enormous Ice Shelf Collapse Imminent in Antarctica" ChattahBox
The enormous Wilkins Ice Shelf, running the span of several thousand kilometers, is on the verge of collapse, due to melting caused by global warming.
Scientists have returned to Antarctica, after a scope last summer showed that the last threads of ice that kept it from collapsing into the ocean were nearly melted through, making it one of 25,000 square kilometers of ice shelf that has disappeared in recent years.
The phenomenon is being caused by global warming, as temperatures in the area drastically increase. Many are worried about the long term, or even permanent damage, this event points to.
“This ice shelf and the nine other shelves that we have seen with a similar trajectory are a consequence of warming,” David Vaughan, a researcher with the British Antarctic Survey, told local science journals.
“Miraculously we’ve come back a summer later and it’s still here. If it was hanging by a thread last year, it’s hanging by a filament this year.”
"Study: Antarctica joins rest of globe in warming" by SETH BORENSTEIN, AP
Antarctica, the only place that had oddly seemed immune from climate change, is warming after all, according to a new study.
For years, Antarctica was an enigma to scientists who track the effects of global warming. Temperatures on much of the continent at the bottom of the world were staying the same or slightly cooling, previous research indicated.
The new study went back further than earlier work and filled in a massive gap in data with satellite information to find that Antarctica too is getting warmer, like the Earth's other six continents.
The findings were published in Thursday's issue of the journal Nature.
"Contrarians have sometime grabbed on to this idea that the entire continent of Antarctica is cooling, so how could we be talking about global warming," said study co-author Michael Mann, director of the Earth System Science Center at Penn State University. "Now we can say: no, it's not true ... It is not bucking the trend."
The study does not point to man-made climate change as the cause of the Antarctic warming - doing so is a highly intricate scientific process - but a different and smaller study out late last year did make that connection.
"We can't pin it down, but it certainly is consistent with the influence of greenhouse gases," said NASA scientist Drew Shindell, another study co-author. Some of the effects also could be natural variability, he said.
The study showed that Antarctica - about one-and-a-half times bigger than the United States - remains a complicated weather picture, especially with only a handful of monitoring stations in its vast interior.
The researchers used satellite data and mathematical formulas to fill in missing information. That made outside scientists queasy about making large conclusions with such sparse information.
"This looks like a pretty good analysis, but I have to say I remain somewhat skeptical," Kevin Trenberth, climate analysis chief at the National Center for Atmospheric Research, said in an e-mail. "It is hard to make data where none exist."
Shindell said it was more comprehensive than past studies and jibed with computer models.
The research found that since 1957, the annual temperature for the entire continent of Antarctica has warmed by about 1 degree Fahrenheit, but still is 50 degrees below zero. West Antarctica, which is about 20 degrees warmer than the east, has warmed nearly twice as fast, said study lead author Eric Steig of the University of Washington.
East Antarctica, which scientists had long thought to be cooling, is warming slightly when yearly averages are looked at over the past 50 years, said Steig.
However, autumn temperatures in east Antarctica are cooling over the long term. And east Antarctica from the late 1970s through the 1990s, cooled slightly, Steig said.
Some researchers skeptical about the magnitude of global warming overall said that the new study didn't match their measurements from satellites and that there appears to be no warming in Antarctica since 1980.
"It overstates what they have obtained from their analysis," said Roger Pielke Sr., a senior research scientist at the University of Colorado.
Steig said a different and independent study using ice cores drilled in west Antarctica found the same thing as his paper. And recent satellite data also confirms what this paper has found, Steig added.
The study has major ramifications for sea level rise, said Andrew Weaver at the University of Victoria in Canada. Most major sea level rise projections for the future counted on a cooling - not warming - Antarctica. This will make sea level rise much worse, Weaver said.
"N.C. among most at risk to rising seas" by Wade Rawlins, Charlotte Observer
With its long low coastline and large land area less than two feet above sea level, North Carolina is among the states most vulnerable to sea-level rise, a new federal report warns.
The new report focuses on the coastal states from North Carolina to New York where the rates of sea level rise are moderately high. The region has extensive coastal development, a high population and is likely to be at increased risk.
After Florida and Louisiana, North Carolina and Texas have the largest land areas threatened by sea-level rise.
“You're vulnerable,” said Jim Titus, project manager for sea-level rise for the U.S. Environmental Protection Agency and lead author of the report, “Coastal Sensitivity to Sea Level Rise: A Focus on the Mid-Atlantic Region.” “The people whose land could be permanently submerged aren't even flooded today.”
A rise in sea level increases the vulnerability of development in coastal floodplains and diminishes the rate at which low-lying areas drain. It will result in a loss of wetlands in the mid-Atlantic.
Rising temperatures cause ocean waters to warm and expand, like water heated in a tea kettle. In addition, rising temperatures near the poles cause massive ice sheets to melt, adding to the volume of water.
The report predicts that coastal erosion will occur at higher rates as sea level rises. Particularly in the sandy shore of the mid-Atlantic coast, the report says, it is nearly certain that barrier islands, spits and coastal headlands will erode faster due to sea-level rise. The Outer Banks are particularly vulnerable.
The report, produced by a collaboration among agencies including the U.S. Geological Survey, the National Oceanic and Atmospheric Administration and the Department of Transportation, offers three scenarios for sea-level rise by 2100: A rise of about 16 inches; of about two feet, and of about three feet.
In 2007, an international scientific panel projected that sea level would likely rise between 7 inches and two feet by 2100. Those estimates do not take into account any contribution from rapid changes in ice flow from Antarctica or Greenland.
Rising sea levels might be especially disastrous to North Carolina, as some sections of the coast are slowly sinking, magnifying the effects of rising seas.
Tide-gauge readings in the mid-Atlantic indicate that relative sea level rise (the combination of rising waters and sinking land) was generally higher – by about a foot – than the global average during the 20th century.
If sea level should rise more than three feet during the 21st century, the report says, “it is likely that some barrier islands in this region will cross a threshold” destabilizing and breaking apart.
Rob Young, director of the Program for the Study of Developed Shorelines at Western Carolina University, said the report underscored that sea-level rise is a real management concern.
“There is some very important stuff in here that North Carolinians should take seriously,” said Young, who said state policy-makers and coastal communities should use a three-foot sea level rise by 2100 as a target.
“Whether sea level is rising is not something scientists argue about it,” Young said. “It is. It's different than an argument about whether humans are causing global warming. We have directly measured an acceleration … over the last two decades.”
As sea level rises, the most basic decision that states and beach communities must wrestle with is whether to try to hold back the sea or let nature take its course. Both have costs. Replenishing sand on eroding beaches allows houses and businesses to remain in place for a period of time, but is expensive to maintain. Retreating from the rising sea avoids the costs but concedes a loss of land and, in a worse case, entire communities, the report notes.
Greg Rudolph, shore protection officer for Carteret County, said people generally accept that sea level is rising. But planning for something that is occurring over decades is difficult.
“Let's face it, we live on four-year cycles when people are elected,” Rudolph said. “Not many people are going to plan out 14 years or 21 years in advance.”
Beach towns representing about a third of the North Carolina's 325 miles of coastline are seeking to replenish the sand on their beaches. But holding the beach may be an increasingly expensive response if erosion rates increase. “One size does not fit all,” Rudolph said.
Titus, of EPA, said the report shows it is rational to take into consideration the risk of accelerated sea-level rise.
“A reasonable hope is people making decisions will start factoring it in, rather than continuing to assume that sea level is stable,” Titus said. “Anyone who is making an investment, a regulation or a policy, has good reason to ask: how does sea level change the outcome of my decision?”
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