-Caveat Lector-
"And our study doesn't even consider the effects of 'global warming'..."
West Antarctic May Melt Completely
By RANDOLPH E. SCHMID
.c The Associated Press
WASHINGTON (AP) - The giant West Antarctic ice sheet has been shrinking for
thousands of year and its eventual disappearance may be inevitable.
At current melting rates that could mean oceans four inches deeper as they
lap at low coastal areas a century from now.
By the time the ice sheet is gone in 7,000 years or so, the water could be 15
to 20 feet deeper, according to a paper in today's edition of the journal
Science.
In recent years, scientists increasingly have been able to document melting
and the discovery of icebergs breaking off from Antarctica, raising concerns
that human-induced climate change could be damaging the Antarctic ice sheet.
But the new paper says the West Antarctic melting began long before any
human-induced climate change.
The future of the West Antarctic ice sheet ``may have been predetermined when
the grounding line retreat was triggered in early Holocene time,'' about
10,000 years ago, according to the paper by a team of scientists led by
Howard Conway of the University of Washington.
The grounding line is the boundary between floating ice and ice thick enough
to reach the sea floor. Scientists determined the line has receded about 800
miles since the last ice age, withdrawing at an average of about 400 feet per
year for the last 7,600 years.
``It seems like the rate (of melting) that has been going since the early
Holocene is similar to the rate right now,'' Conway said in a telephone
interview. ``Collapse appears to be part of an ongoing natural cycle,
probably caused by rising sea level initiated by the melting of the Northern
Hemisphere ice sheets at the end of the last ice age.''
Continued shrinking of the ice sheet, perhaps even complete disintegration,
``could well be inevitable,'' the report concluded.
Conway said the melting annually contributes about 1 millimeter - nearly
one-twenty-fifth of an inch - to sea-level rise.
While the study indicates global warming is not causing the melting, climate
change remains a potential problem, Conway said: ``Global warming could well
speed the process. Our study doesn't address that problem.''
Environmentalists have grown concerned that industrial chemicals added to the
atmosphere are trapping heat somewhat like a greenhouse, causing the Earth's
temperature to increase. There is disagreement, however, about the process
and how great a hazard it may pose.
Conway's report is one of three in this issue of Science focusing on the
Antarctic ice sheet. In the others:
Scientists studying satellite-based measurements found a complex system of
tributaries feeding major rivers of ice on the West Antarctic Ice Sheet. This
web of tributaries forms a transition zone between the sluggish inland ice
and the swiftly moving ice streams closer to the margins.
Other researchers, using the ages of volcanic debris that erupted onto the
ice sheet, reconstructed the past elevation of the West Antarctic Ice Sheet
as it began to melt just after the end of the last ice age. They concluded
the sheet was not the source of a massive flow of meltwater into the oceans
10,000 years ago.
West Antarctica is the section of the continent south of the tip of South
America. It is covered by an ice sheet that extends about 360,000 square
miles - close to the combined areas of Texas and Colorado.
Conway's team calculated the movement of the grounding line using evidence
gathered from raised beaches and radar imaging of subsurface ice structures.
The timing of start of the melting was determined by carbon-14 dating of
samples found on raised beaches.
DECLARATION & DISCLAIMER
==========
CTRL is a discussion and informational exchange list. Proselyzting propagandic
screeds are not allowed. Substance�not soapboxing! These are sordid matters
and 'conspiracy theory', with its many half-truths, misdirections and outright
frauds is used politically by different groups with major and minor effects
spread throughout the spectrum of time and thought. That being said, CTRL
gives no endorsement to the validity of posts, and always suggests to readers;
be wary of what you read. CTRL gives no credeence to Holocaust denial and
nazi's need not apply.
Let us please be civil and as always, Caveat Lector.
========================================================================
Archives Available at:
http://home.ease.lsoft.com/archives/CTRL.html
http:[EMAIL PROTECTED]/
========================================================================
To subscribe to Conspiracy Theory Research List[CTRL] send email:
SUBSCRIBE CTRL [to:] [EMAIL PROTECTED]
To UNsubscribe to Conspiracy Theory Research List[CTRL] send email:
SIGNOFF CTRL [to:] [EMAIL PROTECTED]
Om
