Greenland's Melting Ice Sheets Will Raise Sea Level 23 Feet?
Written
by
Science
and
Public
Policy
Institute
via
RightSideNews
July
30,
2008
THE
SCARE:
An
article
in
the
New
York
Times
in
late
July
2008
by
an
author
promoting
a
forthcoming
book
about
"global
warming"
calls
the
Greenland
ice-sheet
"one
of
'global
warming's'
most
disturbing
threats.
The
article
says:
"The
vast
expanses
of
glaciers -
massed,
on
average,
1.6
miles
deep -
contain
enough
water
to
raise
sea
levels
worldwide
by
23
feet.
Should
they
melt
or
otherwise
slip
into
the
ocean,
they
would
flood
coastal
capitals,
submerge
tropical
islands
and
generally
redraw
the
world’s
atlases.
The
infusion
of
fresh
water
could
slow
or
shut
down
the
ocean’s
currents,
plunging
Europe
into
bitter
winter.”
The article continues that ocean warming eats the ice sheet from beneath, causing glaciers to calve and melt faster, changing patterns of migration and hence of hunting, which, it says, has a positive effect: warm-water cod have returned, and shops can now offer locally-grown vegetables. Recession of ice along the shore has exposed pockets of lead, zinc, and bauxite. More than 30 billion barrels of oil may also be reachable if there is further melting. Yet the thrust of the article is Apocalyptic.
THE TRUTH: The “Greenland is melting” scare is an old one, and long discredited. It was first given widespread currency by Al Gore, not a climatologist, in his sci-fi comedy horror movie about the climate – a movie that is now an international joke for serious, serial, scientific inaccuracy. In October 2007, a UK High Court Judge ordered the Department of Education to issue a disclaimer about several inaccuracies in the movie before innocent schoolchildren could be exposed to it. The learned Judge’s finding about Gore’s claim that sea level would imminently rise by 20 ft was blunt:
“This is distinctly alarmist and part of Mr. Gore’s ‘wake-up call’. It is common ground that if Greenland melted it would release this amount of water, but only after, and over, millennia, so that the Armageddon scenario he depicts is not based on any scientific view.”
The UN’s climate panel, the IPCC (Intergovernmental Panel on Climate Change), also fueled the scare when its bureaucrats, after the scientists had submitted the final draft of its 2007 report, inserted a table that had not been in the scientists’ draft, in which they had ingeniously right-shifted four decimal points so as to exaggerate tenfold the supposed contribution of melting ice-sheets and glaciers to sea-level rise:
Metres per century 1961-2003 1993-2003
- Thermosteric expansion 0.042 0.160
- Glaciers and ice-caps 0.050 0.077
- Greenland ice-sheets 0.050 0.210
- Antarctic ice-sheets 0.140 0.210
- IPCC's sum of lines 1-4: 0.110 0.280
The Viscount Monckton of Brenchley earned his share of the Nobel Peace Prize by writing to the IPCC on the morning of publication, demanding - and getting - a correction of this maladroit and unscientific attempt to lend support to the unscientific fantasies of Gore.
Al Gore's movie said...
Gore: "Two canaries in the coal mine. The first one is in the Arctic. Of course the Arctic Ocean has a floating ice cap, Greenland on its side there. I say canary in the coal mine because the Arctic is one part of the world that is experiencing faster impact from global warming. This is the largest ice shelf in the Arctic, the Ward Hunt Ice Shelf. It just cracked in half a year ago. The scientists were astonished."
But what do the scientific studies and the peer-reviewed scientific literature (as opposed to the layman Gore or the error-prone IPCC) have to say about Greenland, and about sea level generally? ...
"Temperature records show that the Arctic was in fact warmer in the 1930s and 1940s than it is today"
"Northern Hemisphere snow cover reached a new record in 2001"
"A new record in 2001 for Northern Hemisphere winter snow cover"
But this new record was easily surpassed in 2007, when, for the first time since satellite records began 30 years ago, winter sea ice extent at both Poles reached record highs. Somehow most of the media that had mentioned the record loss of summer sea-ice in the Arctic in 2007 failed to mention the record growth of winter sea ice at both Poles that very winter.
The ice cap at the North Pole has certainly been thinning ever since US nuclear submarines took the first measurements in the 1950s. However, a paper by NASA scientists last year says the reason has nothing to do with "global warming". The warmer Arctic has been caused by the current warming phase of the Atlantic Multidecadal Oscillation, driving warm tropical waters poleward and also causing winds to take a more southerly direction.
Also, a very recent paper has shown considerable and hitherto-unsuspected undersea volcanic activity at 73 degrees North latitude on the mid-Atlantic ridge in the Greenland-Iceland gap, with temperatures at the outlets of the volcanic vents at 570 degrees F.
Among the many facts that the article in the New York Times is careful not to mention is one central fact: that in the early 1940s it was warmer in the Arctic than it is today.
Chylek et al. (2004) confirm that temperatures along Greenland's coasts are about 1 degree Celsius below their 1940 levels, despite half a century of "global warming". They say -
"Current coastal temperatures are about 1°C below their 1940 values." Furthermore, "at the summit of the Greenland ice sheet the summer average temperature has decreased at the rate of 2.2°C per decade since the beginning of the measurements in 1987." Ocean currents and volcanic activity are not the only natural influences on Arctic temperatures. The apparently random fluctuations in Arctic temperatures in the past 125 years are more closely correlated with changes in solar activity than with the ever-upward increases in atmospheric CO2 concentrations. It is scientifically perverse to make an unqualified attribution of the observed thinning of the Arctic ice-cap to anthropogenic "global warming" when, compared with the early 20th century, the Arctic has been cooling. One story that did not make it into the New York Times article - sealers were trapped in Arctic ice in April 2007 -
The total extent of summer Arctic sea-ice has been declining, and there has been much alarm about it in the media, but the decline has in fact been modest -
Total extent of Arctic sea-ice, 1978 to 2004 (National Snow and Ice Data Center)
Even if the entire Arctic ice-cap were to melt, as it probably did in the Bronze Age, Roman and Mediaeval warm periods, not a single millimeter of sea-level rise would result. However, between 1982 and 1999, in winter, there was an unpredicted cooling trend over the Arctic ocean -
Winter surface cooling of the Arctic ocean, 1982-1999 (Wang & Key, 2003) The Arctic climate is and has always been highly variable, as the two pictures from Beechey Island in the 1850s show. The illustrations are of scenes at the same season of the year, just three years apart -
Beechey Island shows strong climate variability. Above: 5 September 1850. Below: 21 August 1853.
Greenland has, in fact, been warmer than the present for most of the past 10,000 years -
Mean temperature at the summit of the Greenland ice-sheet (thousands of years before present)
One of the most careful surveys of the thickness of the Greenland ice-sheet was conducted by Johannesen et al. (2005). Their conclusion (not reported by most of the mainstream media) was that the mean increase - yes, increase - in the thickness of the entire, vast ice-sheet that covers the interior of Greenland was an impressive 5.4 cm (>2 in) per year in the decade 1992-2003:
"Colors indicate ice-sheet elevation change rate in cm/year ... from ... satellite altimeter data, 1992-2003. The spatially averaged increase is 5.4 ± 0.2 cm/year." Source: Johannesen et al., 2005
There has also been considerable discussion on the well-funded alarmist blogs about "Warming Island" - an icy peninsula that became an island a few years ago, allegedly because of "global warming". The inconvenient truth, however, is that an explorer in the late 1950s drew a map of the relevant stretch of the Greenland coast as it then was, clearly showing "Warming Island" as an island.
Natural changes had caused the ice to disappear in the 1940s, to re-form in the 1960s, and to disappear again recently. The emergence of "Warming Island" as evidence of "global warming" is in fact evidence of natural climate variability, and nothing more.
The article in the New York Times repeats one of the most misleading canards currently circulating among alarmists - to the effect that the Greenland ice sheet might be melted from beneath, lubricated by meltwater plunging through "moulins" from the surface, so that it might suddenly reach a "tipping-point" and slide into the sea. However, the vast majority of the Greenland ice-sheet is ringed by coastal mountains. Even if there were anything new about summer meltwater passing down through the ice (a long-established phenomenon), the imagined "lubrication" would not and could not allow the entire ice-sheet to slip into the sea, because the mountains are in the way.
Finally, it is necessary to dispose of the article's repetition of a long-outdated theory that somehow the thermohaline circulation - the great current that incorporates the Gulf Stream and gives Europe a milder climate than its northerly latitude would otherwise allow - might stop flowing if ice from Greenland were to melt at an accelerated rate. Setting aside the fact that there is little sign of such acceleration (indeed, the Viking burial-ground at Hvalsey in the south-west is still under permafrost, indicating that temperatures in Greenland today are cooler than they were in the mediaeval warm period), there is no danger of a cessation in the thermohaline circulation. As Professor Carl Wunsch of the Massachusetts Institute of Technology has put it -
"Shut-off would imply repeal of the law of conservation of angular momentum. ... Widely disseminated and grossly oversimplified pictures showing the ocean as a ‘conveyor belt' have misled people into thinking ocean circulation is driven by a sinking motion at high latitudes."
Al Gore, and the New York Times, please note. End of scare.