Antarctic ice shelf retreats have happened before

The retreat of Antarctic ice shelves is not new according to research published this week (24 Feb) in the journal Geology by scientists from Universities of Durham, Edinburgh and British Antarctic Survey (BAS). A study of George VI Ice Shelf on the Antarctic Peninsula is the first to show that this currently `healthy' ice shelf experienced an extensive retreat about 9500 years ago, more than anything seen in recent years. The retreat coincided with a shift in ocean currents that occurred after a long period of warmth. Whilst rising air temperatures are believed to be the primary cause of recent dramatic disintegration of ice shelves like Larsen B, the new study suggests that the ocean may play a more significant role in destroying them than previously thought.

The University of Durham's, Dr Mike Bentley, one of the leaders of the project said, `We know that rising air temperatures can break up ice shelves but there has been a suspicion for some time that the role of the ocean may have been underestimated. This is some of the first evidence that a shift in ocean currents can actually destroy ice shelves. In this case it's possible that a preceding warm period may have primed the ice shelf to disintegrate when the ocean currents shifted.'

The scientists analysed sediments from the bottom of a freshwater lake close to the edge of the present George VI Ice Shelf. The results revealed that about 9500 years ago the ice shelf retreated, allowing the sea to flood into the lake. The ice shelf didn't reform until 1500 years later, and has been present ever since.

The findings are particularly relevant for other studies on the West Antarctic Ice Sheet where scientists have found that a relatively warm current, Circumpolar Deep Water, is causing high melt rates on the underside of an ice shelf in Pine Island Bay*. The gradual removal of this ice shelf may be causing the glaciers inland to flow faster, which could lead to enhanced drainage of part of the West Antarctic Ice Sheet, and a consequent rise in sea level.

George VI ice shelf lies south of the recently collapsed ice shelves along the Antarctic Peninsula. British Antarctic Survey scientists have monitored a very slow retreat of the ice shelf front since its discovery in the mid-20th century.

It is important to appreciate that ice shelf collapses have happened before. For example, BAS scientists Carol Pudsey and Jeff Evans reported that the Prince Gustav Ice Shelf, which collapsed in 1995, had also collapsed several thousand years ago. This new study is the first to show that a currently `healthy' Antarctic Peninsula ice shelf has retreated in the past, and that the ocean may have been involved in the past retreat.

What this study shows us is that these are not random occurrences but that they are closely linked to changes in ocean circulation (George VI Ice Shelf) or periods of atmospheric warming (Prince Gustaf Channel Ice Shelf). These historical patterns mean that scientists can be increasingly confident that the present-day collapses of the Antarctic ice shelves are intimately connected to changes in our climate and our oceans.

In 2001 the Intergovernmental Panel on Climate Change (IPPC) predicted future sea level rise on the assumption that the Antarctic ice sheet would not make a significant contribution over the next one hundred years. Recent data from the Pine Island and Thwaites glaciers in Antarctica suggest that this area is making a contribution, but whether this is a short-term fluctuation, or a result of recent or ancient climate change, is an open question. Our ability to predict the future of this part of the West Antarctic ice sheet is limited and basic information such as the ice sheet thickness, conditions beneath the ice at bedrock, and past ice sheet history are required to build numerical models that will allow robust prediction.

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No End to the Energy Stalemate

In December 2004, the National Commission on Energy Policy (NCEP) released a report titled "Ending the Energy Stalemate: A Bipartisan Strategy to Meet America's Energy Challenges." The group claims to have established "a constructive center in the often polarized debate over national energy policy," and indeed its report contains ideas and recommendations often found in reports produced by industry groups or by environmental advocacy groups but rarely in both.

The report contains some good ideas, and the studies prepared by subcontractors to the commission, listed in an appendix to the report, may contain valuable original research. (This writer has not read them.) However, the report's recommendations often seem to combine the worst, rather than the best, of what these two sides in the debate have to offer.

Rather than setting their private interests and agendas aside, corporate members of the commission call on taxpayers and consumers to subsidize and bear the financial risk of programs that would benefit them, while the commission's professional environmental advocates make little effort to temper their alarmist agenda with sound science or common sense.

Taxpayers, consumers, many credible scientists, economists, moderates, and conservatives have all been left out of this "bipartisan strategy." Behind the big PR budget, the NCEP is just another liberal advocacy group calling for more government spending and regulating.

The NCEP was not created by its 16 commissioners. It was founded in 2002 by the William and Flora Hewlett Foundation and four "partner" foundations: Pew Charitable Trusts, John D. and Catherine T. MacArthur Foundation, David and Lucile Packard Foundation, and the Energy Foundation.

According to the Capital Research Center, a philanthropy watchdog organization, all five foundations fund primarily left-of-center causes. For example, the William and Flora Hewlett Foundation is a major contributor to the Tides Center, which is believed to funnel dollars to radical and even eco-terrorist groups, as well as the Union of Concerned Scientists, Environmental Defense Fund (now called Environmental Defense), Worldwatch Institute, and Sierra Club. None of these groups can be called moderate or bipartisan......

Like its funders, the staff of the NCEP leans to the left. Jason Grumet, executive director of the NCEP, was previously executive director of the Northeast States for Coordinated Air Use Management (NESCAUM), where he advocated adoption of California emission standards, mandatory production and sale of zero-emission vehicles in the Northeast, and tighter regulation of air quality. Deputy director Lisel Loy was President Clinton's staff secretary from 2000 to 2001. Paul W. Bledsoe, NCEP's director of communications and strategy, was a senior vice president with Fenton Communications, the public relations firm used by the Natural Resources Defense Council to create the infamous ALAR scare of 1989. Drew Kodjak, program director, worked for Grumet at NESCAUM and also is an advocate of zero-emission vehicles.

The result is a report that differs only in minor ways from those released by many leftist environmental advocacy groups.....

The NCEP seeks to win corporate and Republican support for its recommendations by validating some of their concerns. For example, on the topic of global warming, the Commission says "the United States must take responsibility for addressing its contribution to the risks of climate change, but must do so in a manner that recognizes the global nature of this challenge and does not harm the competitive position of U.S. businesses internationally." (p. ix)

The Commission says the way to do this is to focus, as the Bush administration has, on the emission intensity of the economy (tons of emissions per dollar of GDP) rather than actual emissions. It would phase in caps and emission permit trading and include a "safety valve mechanism" that allows more permits to be issued if compliance costs exceed $7 per metric ton.

The report also supports construction of a natural gas pipeline from Alaska, (p. 46) removal of regulatory barriers and uncertainty that stand in the way of new energy infrastructure, (p. 84) siting new liquid natural gas receiving terminals, (p. 47) safe storage of radioactive waste, (p. 60) and larger public investments in clean coal technology (p. 51) and a new generation of nuclear power generators (p. 57).

Each of these items often appear on the wish list of corporations and business groups, but of course that does not mean they would be good public policy. Removing regulatory barriers is almost always good public policy, but subsidies in most cases are wasted on producing products for which there is no market demand or giving windfalls to companies that would do much the same things without subsidies. In either case, wealth is forcibly transferred from one group to another without producing any social gains.....

On the controversial matter of global warming, the report comes perilously close to repeating the now meaningless mantra of a "growing scientific consensus" on the need for immediate action (meaningless because science does not advance through consensus and because scientists are leaving the alarmist camp, as demonstrated just this month by the resignation of Chris Landsea from the IPCC). However, the Commission narrowly avoids the error by leaving out any mention of how much warming can be attributable to the human presence and what harm, if any, that warming could cause. (p. 20)....

On its face, it appears that the business members of the Commission signed off on the environmentalists' agenda in exchange for support of higher taxes and massive subsidies to businesses. It may be a fine deal for the 16 Commissioners, but it is very bad public policy for the rest of the country.

More here

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Many people would like to be kind to others so Leftists exploit that with their nonsense about equality. Most people want a clean, green environment so Greenies exploit that by inventing all sorts of far-fetched threats to the environment. But for both, the real motive is to promote themselves as wiser and better than everyone else, truth regardless.

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