-Caveat Lector- A HREF="http://www.ctrl.org/"
/A -Cui Bono?-
Friday, 11 February, 2000, 11:39 GMT
Limited sea rises expected
from:
http://news.bbc.co.uk/hi/english/sci/tech/newsid_639000/639241.stm
Sea levels will rise by "several tens of
centimetres" over the next century,
according to Australian research.
The finding is based on a computer
model of future climate change that
assumes the Earth's surface
temperatures will rise by two to three
degrees over the coming century.
The Antarctic Co-operative Research
Centre (CRC) says melting ice in both
Antarctica and Greenland will cause
some increase in sea levels, but
stresses that we are unlikely to see
the catastrophic melting forecast in
some quarters.
The centre's director, Professor Garth
Paltridge, told BBC News Online that
he hoped the research would help
dispel the myth that we are heading
for a drowning world as a result of
global warming.
Informed opinion
"Many of the public are still under the
impression that there is a distinct
possibility the ice cap on Antarctica
will slide off into the sea and melt,
thereby raising sea levels by quite
disastrous amounts over the next few
years or decades," he said.
"One often hears this sort of
implication when, for instance,
somebody reports that a particularly
large part of an ice shelf has broken
off from somewhere in Antarctica. It
seems well worth while to make the
point that informed scientific opinion
does not agree with such extreme
scenarios."
The Antarctic ice sheet is a very
important focus for climate change
research, not least because it helps
to cool the Earth by reflecting the
Sun's energy back into space. Were it
to melt completely, it would add 55
meters to global sea levels. But the
Antarctic CRC says this is not going
to happen with a warming of just two
or three degrees.
However, it is possible, it says, that
the projected warming could increase
the flow rate of grounded ice into the
sea, adding perhaps one or two
meters to sea levels over the next
one or two thousand years.
Higher evaporation
The Antarctic CRC says its
calculations suggest that a significant
proportion of the slightly smaller
Greenland ice sheet could disappear -
but again over a period of millennia.
Indeed, the centre believes that in
the short term, there will be
relatively little melting of the
ice-sheets with perhaps even an
increase in volume of the Antarctic
sheet as a result of greater snowfall
caused by higher evaporation from
warmer oceans.
Thus, for the next century or two, the
rise worldwide rise in sea levels will
come mainly from thermal expansion
of the oceans and the melting of
non-polar glaciers.
The findings are part of Australia's
contribution to the Intergovernmental
Panel on Climate Change (IPCC), an
international body that is reviewing
scientific estimates on long-term
climate change. Part of the IPCC's
role is to put together best-guess
scenarios for the future.
Model problems
There will be some scientists who will
reject this latest work because, like
much of the other material assessed
by the IPPC, it is based on computer
models which sceptics of global
warming regard as deeply flawed.
The models have to incorporate a
multitude of complex interactions,
including cloud formation,
precipitation, oceanic heat transport
and sea-ice formation. Many of these
measurements have to be averaged
