A chunk of Antarctic ice about seven times the size of Manhattan suddenly collapsed, putting an even greater portion of glacial ice at risk, scientists said Tuesday...It was the edge of the Wilkins ice shelf and has been there for hundreds, maybe 1,500 years.
This is the result of global warming, said British Antarctic Survey scientist David Vaughan.
The rest of the Wilkins ice shelf, which is about the size of Connecticut, is holding on by a narrow beam of thin ice. Scientists worry that it too may collapse. Larger, more dramatic ice collapses occurred in 2002 and 1995.
Vaughan had predicted the Wilkins shelf would collapse about 15 years from now.
Scientists said they are not concerned about a rise in sea level from the latest event, but say it's a sign of worsening global warming.
Such occurrences are "more indicative of a tipping point or trigger in the climate system," said Sarah Das, a scientist at the Woods Hole Oceanographic Institute._________________________________________________________________________________
Now read:
“Huge Antarctic ice-sheet disintegrates”
The scare: “A
13,680-square-kilometer (5,282-square-mile) ice shelf, part of the Wilkins Ice
Shelf, has begun to collapse because of rapid climate change in the
fast-warming Antarctic Peninsula. The Wilkins is one of a string of ice
shelves that have collapsed in the West Antarctic Peninsula in the past 30
years. The Larsen B became the most well-known of these, disappearing in just
over thirty days in 2002. The Prince Gustav Channel, Larsen Inlet, Larsen A,
Wordie, Muller, and the Jones Ice Shelf collapses also underscore the
unprecedented warming in this region of Antarctica.”
The truth: The Wilkins Ice
Shelf, like many of the ice shelves surrounding the Antarctic Peninsula, was
not there in the mediaeval warm period, and may also have been absent in the
Roman warm period and in the 2000-year-long Holocene Climate Optimum, when
global temperatures were considerably higher than they are today. Lead
Scientist Ted Scambos of the US National Snow and Ice Data Center, who first
spotted the disintegration in March, said, “We believe the Wilkins has been in
place for at least a few hundred years.” This implies that it has indeed been
absent before.
Media reports usually fail to admit that the
Antarctic Peninsula represents just 2% of the total Antarctic land mass, and a
still smaller proportion of its ice mass. The seven ice shelves that have
already disintegrated on the Atlantic Peninsula represent a combined area 1/55
the size of Texas.
The ice-shelf disintegration is nothing new. Very
large icebergs break away from Antarctica all the time, to be replaced again
in colder times. Whaling ships’ logs provide some of the earliest climate data
available on Antarctica: in those logs, very large icebergs hundreds of miles
long have been recorded in previous centuries.
The media usually fail to report that in the past
half-century since regular Antarctic-wide temperature records were first kept
the Antarctic as a whole has been cooling (Doran et al., 2002).
The cooling Antarctic
The warming, as the graphic shows, is largely
confined to the seas surrounding the Antarctic, and is particularly pronounced
in the region of the Antarctic Peninsula. Undersea volcanic activity may be
partly to blame. Another factor not usually mentioned in the media is the
warming effect of the recently-ended 70-year Solar Grand Maximum, during which
the Sun was more active, and for longer, than at almost any similar period in
the 11,400 years since the end of the last Ice Age (Usoskin et al., 2003;
Hathaway, 2004; Solanki et al., 2005). Multidecadal ocean changes are also a
likely factor.
The media are also usually silent about the fact that
there has been more sea ice in the Antarctic recently than at any previous
time since satellite records were first kept 30 years ago:
Antarctic sea-ice extent is now at record levels. The trend, in keeping
with the general cooling of Antarctica over the past half-century, is
generally upward.
Conclusion: The media that reported
the Wilkins disintegration scare did not give all the facts. There will be no
further disintegration until January 2009, if then. Melting ice shelves add
not a millimetre to sea level: the ice is already floating. It is doubtful
whether anthropogenic effects have more than a minuscule effect on Antarctic
ice. Solar, oceanic and volcanic changes are likelier influences. There is
more ice in Antarctica than 50 years ago. Moerner (2004) says there is no
reason to suppose that sea level will rise this century by much more than the
8 inches observed in the 20th century. The IPCC says sea level will only rise
by 20ft after several millennia, chiefly through natural causes.
End of scare.