An interesting interchange, with many valuable references. The question of
melting glaciers and other evidence of global warming is certainly worth
debating, though the signal-to-noise ratio will probably be slim enough for
the next several years to preclude any definitive resolution.
I would be curious, though, to know the degree of consensus in the sample of
opinion represented by this list serve on the answers to the following
sequence of questions:
1. Is the evidence that atmospheric carbon dioxide levels are steadily
increasing reliable?
2. Will a continuing increase in atmospheric carbon dioxide concentration,
AT SOME POINT, be sufficient to overwhelm all other possibly confounding
variables (such as increased cloud cover), and lead to unequivocal warming?
3. Will the deleterious effects of this warming on the habitability of the
planet, AT SOME POINT, outweigh any local benefits such as increased
rainfall, or global benefits such as enhanced photosynthesis?
4. Given the difficulty in reversing the trend to increasing carbon dioxide
levels, once established, and given that the locations of the "points" in
items 2 and 3 are unknown, is there any basis for assuming there is a
comfort zone where we can afford to wait and see if it matters?
For those who would answer "yes, yes, yes, no," the question of whether we
can see the signal yet would be less urgent than the question of how we go
about doing something about it.
Paul Chalmer
NCMS
Voice: (734) 995-4911
Fax: (734) 995-1150
[log in to unmask]
-----Original Message-----
From: Charles Dolci [mailto:[log in to unmask]]
Sent: Monday, March 18, 2002 4:07 PM
To: [log in to unmask]
Subject: [EN] EARTH'S ICE MELTING FASTER THAN PROJECTED
Joe posted an article from the Earth Policy Institute about melting
glaciers, which
article attributed the cause to "global warming".
I guess I could debate whether or not glaciers around the world are actually
melting,
but I don't think I need to. In fact, I do believe that many (but not all)
glaciers
are melting. The question though is why, and what are the causes.
But let's look at some facts about melting glaciers.
The U.S. National Park Service has a website
(http://www.nps.gov/glba/adhi/adhi1.htm)
devoted to the history of Glacier National Park. They have an interesting,
and
relevant, article on the famous naturalist, John Muir.
"Chapter I:
Indigenous People
In the fall of 1879, John Muir canoed up southeast Alaska's Inside
Passage from Fort Wrangell to Glacier Bay, accompanied by the
Rev. S. Hall Young and three Tlingit guides. On this first of
four visits to Glacier Bay, Muir spent several days exploring
the large fjord's various inlets and tributary glaciers, deeply
inspired by the treeless, glacier-polished terrain. A keen observer
of glaciated landforms, Muir instantly recognized that this watery
basin rimmed by high mountain ranges and devoid of mature forest was
the scene of a phenomenally rapid and sustained glacial recession.
The constant crack and rumble of ice breaking off of the unstable
glacier fronts further impressed him with the area's extraordinary
dynamism. Muir, like many others who followed him, found in Glacier
Bay a unique setting for contemplating how the land might have
looked
as it emerged from the Ice Ages."
Note: by 1879 - long before the build up of man-made green house gases the
glaciers
in Glacier Bay Alaska had already experienced a "...a phenomenally rapid and
sustained glacial recession..."
********
Also from the history, evidence that some of the melting had occurred even
earlier:
"It is now estimated by geologists and plant ecologists that this
recent glaciation reached its maximum extent in the eighteenth
century,
completely filling the bay and giving the channel to the south its
name
of Icy Strait. The first explorer to chart this shoreline was
Captain
George Vancouver, who recorded in 1794 a slight indentation
"terminated
by a solid, compact mountain of ice, rising perpendicularly from the
water's edge." By the time of John Muir's exploration in 1879, the
ice mass had receded about fifty miles up the bay.... . ..... In the
lower part of the bay where approximately one hundred years had
passed
since the ice had melted, new vegetative growth included berry
bushes and other edible plants."
Today, cruise ships take tourists to Alaska which allows these tourists (and
apparently some "scientists") to witness the break-up of these glaciers as
huge
chunks of ice fall into the sea. Everyone returns from their adventure
attributing
this to "global warming". But eco-tourism is not new. According to the
National PArk
Service (same cite):
"Tourist accounts invariably described the thunderous calving of
icebergs into the bay as the most memorable spectacle of all. In
the 1880s and 1890s, the Muir Glacier presented an ice wall nearly
300 feet high above the water line and two to three miles across. It
was undoubtedly more active then than any tidewater glacier in
Glacier
Bay today. C. Hart Merriam recorded the scene in his diary on June
9, 1899:
'We arrived a little before 5 p.m., just in time to see the
birth of one of the largest icebergs that ever came off from
Muir Glacier. The terrible event began by the fall of
ordinary
ice masses, weighing perhaps a few thousand tons, which in
some way disturbed the equilibrium of other and vastly
larger
masses until it seemed as if a great part of the face of the
glacier was sinking into the sea. The huge blocks of ice,
200 ft in height above the water and no one knows how thick
below, at first slid & sank gradually, then faster & faster
until they shot down with a thundering roar & disappeared
under the water, to reappear and rise half their height &
disappear again, & then dance and roll & finally shoot
out into the current to move steadily down the bay. The
wave caused by the first great plunge of the iceberg was
one of the most impressive things I ever saw.' "
Again, quoting the history:
"Forty years after Captain Carroll took the first steamship into
Muir
Inlet, Professor William S. Cooper would write that Glacier Bay
offered
a unique setting for ecological study, due to the rapidity with
which
plants were recolonizing vast areas laid bare by retreating
glaciers,
coupled with the "known history of glacier behavior" which made it
possible to date various zones of plant growth.
But is Glacier Bay the only place where glaciers have been retreating for a
period
long before mand-made "greenhouse gases" could have impacted climate. Not
really.
The Department of Glaciology at the University of Washington
(http://www.geophys.washington.edu/Surface/Glaciology/PROJECTS/BLUE_GLAC/blu
e.html )
reported (updated as of March 14, 2002):
"Evidence from terminal moraines indicates that about 1815 the
termini
of both Blue and White Glaciers were joined in Glacier Creek. By the
mid
1950's Blue Glacier had retreated more than 1400 m and it has
remained
near that position for the past 40 years."
And in a report (http://www.for.gov.bc.ca/pgeorge/geomorphology/outburst.htm
) about
the Tulsequah Glacier by Marten Geertsema, British Columbia Ministry of
Forests
describing a glacier located on the eastern margin of the Juneau Icefield in
the
Boundary Ranges of the Coast Mountains near the British Columbia - Alaska
border,
the report states:
"Tulsequah Lake
The evolution of Tulsequah Lake .... In the mid 19th century the
entire bifurcating valley of Tulsequah Lake was occupied by two
Little
Ice Age glaciers flowing from Juneau Icefield, joining together, and
then merging with Tulsequah Glacier. Sometime towards the close of
that century [the 19th centruy - cd], glaciers began to downwaste
and
recede. ...
By about 1920 the tributary glaciers had receded several kilometers
and back into their own valleys increasing the size of Tulsequah
Lake substantially."
From the NORTH CASCADE GLACIER CLIMATE PROJECT 1995 REPORT
(http://www.nichols.edu/departments/glacier/index.html )
Mauri Pelto: Director North Cascade Glacier Climate Project, Nichols College
"IN CLE ELUM RIVER BASIN
This basin has witnessed the steady retreat of its glaciers. Table
2 documents the loss of glacier area in Cle Elum Basin since the
Little Ice Age Maximum. Beginning about 1850, based on the age of
trees on the Little Ice Age moraines, these glaciers began to
retreat.
By 1958, 14 glaciers remained with an area of 2.5 km2. There was
little change from 1958 until 1984. From 1984 to 1994 rapid retreat
has reduced glacier area to 1.6 km2."
What is abundantly clear is that many glaciers began to melt and recede in
the 19th
century (for people from West Palm Beach, Florida that means the 1800's) as
the Earth
was coming out of the Little Ice Age. The earth began to warm out of this
cold spell
long before man-made greenhouse gases could have had any affect on climate.
In addition, the report from the Earth Policy Institute would have us
believe that a
putative 0.6 degree C increase in temperature experienced in the latter half
of the
20th centruy would have had such a major and IMMEDIATE impact on glaciers.
But is all of Earth's ice melting, not really: In an article from Reuters:
Scientists: Ice Sheet Growing
8:55 a.m. Jan. 17, 2002 PST
WASHINGTON -- It may be dropping huge chunks of iceberg that drift
hundreds of miles while they slowly melt, but the West Antarctic Ice
Sheet just may have stopped melting, scientists reported on
Thursday.
Their study, published in Friday's issue of the journal Science, is
sure to provoke controversy and will have to be confirmed by other
experts.
But the team at NASA's Jet Propulsion Laboratory and the California
Institute of Technology say their measurements show the ice sheet is
getting thicker.
"We find strong evidence for ice-sheet growth," Ian Joughlin and
Slawek Tulaczyk wrote in their report.
Joughlin and many others have been taking measurements that show the
ice sheet, known to scientists as the WAIS, has been steadily
melting
since the end of the last Ice Age about 11,000 years ago. It
currently
covers about 360,000 square miles. ......
Joughlin and Tulaczyk used satellite radar to measure the thickness
of
the ice.
They specifically looked at ice streams, which are similar to large,
flowing rivers of ice.
While previous measurements had suggested ice was being steadily
lost,
they found that in fact there was slightly more ice in the areas
feeding
the streams than before. Overall, there were 26 billion tons more
ice
each year, they said -- not the loss of nearly 21 billion tons a
year
that other studies showed.
Richard Allen of Pennsylvania State University wrote in a commentary
that the satellite radar tool could be useful in measuring a huge,
complex ice system that has been extremely difficult to measure.
"Perhaps after 10,000 years of retreat from the ice-age maximum,
researchers turned on their instruments just in time to catch the
stabilization or re-advance of the ice sheet," Allen wrote in a
commentary on the study.
Copyright © 2001 Reuters Limited
Again, from The Department of Glaciology at the University of Washington
(http://www.geophys.washington.edu/Surface/Glaciology/PROJECTS/BLUE_GLAC/blu
e.html )
"Blue Glacier is a small temperate glacier in the Olympic Mountains
of northwestern Washington, 55 km from the Pacific Ocean, with an
altitude range of 1275 to 2350m. Icefalls separate two accumulation
zones, the snowdome (out of view in the top right of the
photograph)
and the cirque, from the lower valley glacier. Compared with other
glaciers in this region and elsewhere in the world, Blue Glacier
has changed little in the past 40 years, in either thickness or
areal extent.
But why have the galciers been retreating the last couple of centuries?
Maybe because
the earth is coming out of the Little Ice Age. From the University of Leeds,
School
of the Environment (http://www.env.leeds.ac.uk/envi2150/climfrm.html ) and
(http://www.env.leeds.ac.uk/envi2150/lecture7/lecture7.html )
"7.3 The Little Ice Age
Widespread documentary evidence demonstrates that Europe moved into
a
cold period during the sixteenth century .... The evidence is
supported
by measurements from the mid-seventeenth century onwards. From
around
1550 for about 150 years, temperatures were lower than at any time
since
the last glacial ended over 10,000 years ago. There is convincing
evidence that the cold period affected the entire Earth, not Europe
alone. Although the period 1550-1700 was the coldest, the entire
period 1200-1850 is often regarded as a single cold episode. This
has
been given the name Little Ice Age. Notable features of the climate
during the coldest part of the Little Ice Age include:
* Permanent snow on the tops of Scottish mountains.
* Reports of sea ice as far south as the Faeroe Islands and
in 1695, sea ice surrounded Iceland.
* Advancing glaciers in Scandinavia."
From the GLACIER MONITORING PROGRAM: NORTH CASCADES Progress Report
( http://www.nps.gov/noca/massbalance.htm) written by:
Jon L. Riedel, North Cascades National Park
Andrew Fountain, U.S.G.S. Water Resources Division
Bob Krimmel, U.S.G.S. Water Resources Division
"Glaciers are one of the most valuable resources in the North
Cascades National Park Service Complex (NOCA). Approximately
one-third
of all the glaciers in the lower 48 states are within the park (Post
et al. 1971). .... Since the end of the Little Ice age in the
late 1800's, glaciers have retreated throughout NOCA, and several
dozen glaciers have probably disappeared (Riedel, 1987)."
From the University of Bergen, Norway a report entitled "THE EFFECT OF
GLACIER
MELTWATER ON AN AGRO-PASTORAL SOCIETY IN HIMALAYA, NEPAL
(http://www.uib.no/people/nboov/melt2k.htm )
"The dynamics of the 'ice-to-water' transition are full of
uncertainties
and hazards, such as glacier lake outbursts , floods and
avalanches.
Glaciers may also expand into the cultivated landscape as happened
during the Little Ice Age .... Most glaciers expanded during The
Little
Ice Age, which was a global cooling period (c. AD 1350 to 1850).
Glaciers
have been retreating since the Little Ice Age, and acceleration of
the this
[sic] retreat has been observed in Himalaya since c. 1970, probably
due
to the 'green-house- effect'."
With respect to their speculation on "acceleration" being due to the
"greenhouse
effect" they offer no evidence. But the facts they can and do provide, is
that the
earth has been warming up for a long time and glaciers have been melting,
long before
any possible impact from "green-house" gases.
Chuck Dolci
------------- Begin Forwarded Message -------------
MIME-Version: 1.0
From: [log in to unmask]
Subject: [EN] EARTH'S ICE MELTING FASTER THAN PROJECTED
To: [log in to unmask]
I have not had time tolook for and check the references yet but thought
there
might be some interest here for those who have not yet seen this item.
Best to all,
Joe
Eco-Economy Update 2002-3
For Immediate Release
March 12, 2002
Copyright Earth Policy Institute 2002
EARTH'S ICE MELTING FASTER THAN PROJECTED
http://www.earth-policy.org/Updates/Update8.htm
|
