[Texgreen] Irresponsible scientists spread fear

[Roger Baker]

But while all these "Chicken Little" scientists run around screeching =20=

about how bad we need to change our American way of life, there are =20
the other kind of scientists making just as much money who tell us we =20=

got nothing to worry about, so who are you going to believe? And =20
anyhow if you read your Bible, you know that if all this did happen, =20
you are going to get to Heaven, slam dunk, and God wants weird stuff =20
to happen sometimes. So lets get back to fighting terrorism, and =20
working to pay off the SUV before something really bad happens. Cheers.

--   Roger


                    *****************************

Global meltdown
<http://environment.guardian.co.uk/climatechange/story/=20
0,,1860560,00.html>
Scientists fear that global warming will bring
climatic turbulence, with changes coming in big
jumps rather than gradually
Fred Pearce
Wednesday August 30, 2006
The Guardian

Richard Alley's eyes glint as we sit in his
office in the University of Pennsylvania
discussing how fast global warming could cause
sea levels to rise. The scientist sums up the
state of knowledge: "We used to think that it
would take 10,000 years for melting at the
surface of an ice sheet to penetrate down to the
bottom. Now we know it doesn't take 10,000 years;
it takes 10 seconds."

That quote highlights most vividly why scientists
are getting panicky about the sheer speed and
violence with which climate change could take
hold. They are realising that their old ideas
about gradual change - the smooth lines on graphs
showing warming and sea level rise and gradually
shifting weather patterns - simply do not
represent how the world's climate system works.

Dozens of scientists told me the same thing while
I was researching my book The Last Generation.
Climate change did not happen gradually in the
past, and it will not happen that way in the
future. Planet Earth does not do gradual change.
It does big jumps; it works by tipping points.

The story of research into sea level rise is
typical of how perceptions have changed in the
past five years. The conventional view - you can
still read it in reports from the UN's
Intergovernmental Panel on Climate Change - holds
that sea levels will start to rise as a pulse of
warming works its way gradually from the surface
through the 2km- and 3km-thick ice sheets on
Greenland and Antarctica, melting them. The ice
is thick and the heat will penetrate only slowly.
So we have hundreds, probably thousands, of years
to make our retreat to higher ground.

Recent research, however, shows that idea is
wholly wrong. Glaciologists forgot about
crevasses. What is actually happening is that ice
is melting at the surface and forming lakes that
drain down into the crevasses. In 10 seconds, the
water is at the base of the ice sheet, where it
lubricates the join between ice and rock. Then
the whole ice sheet starts to float downhill
towards the ocean.

"These flows completely change our understanding
of the dynamics of ice sheet destruction," says
Alley. "Even five years ago, we didn't know about
this."

This summer, lakes several kilometres across
formed on the Greenland ice sheet, and drained
away to the depths. Scientists measured how,
within hours of the lakes forming, the vast ice
sheets physically rose up, as if floating on
water, and slid towards the ocean. That is why
Greenland glaciers are flowing faster, and there
are more icebergs breaking off into the Atlantic
Ocean. That is why average sea level rise has
increased from 2mm a year in the early 1990s to
more than 3mm a year now.

Soon it could be a great deal more. Jim Hansen of
Nasa, George Bush's top climate modeller,
predicts that sea level rise will be 10 times
faster within a few years, as Greenland
destabilises. "Building an ice sheet takes a long
time," he says. "But destroying it can be
explosively rapid."

Alarmist? No. It has happened before, he says.
During the final few centuries of the last ice
age, the sea level rose 20 metres in 400 years,
an average of 20 times faster than now. These
were sudden, violent times. And the melting was
caused by tiny wobbles in the Earth's orbit that
changed the heat balance of the planet by only a
fraction as much as our emissions of greenhouse
gases are doing today.

Violent change

There is more evidence of abrupt and violent
change, most of it culled from ice cores, lake
sediments, tree rings and other natural archives
of climate. We now know that the last ice age was
not a stable cold era but near-permanent climate
change. Towards the end, around 11,000 years ago,
average temperatures in parts of the Arctic rose
by 16C or more within a decade. Alley believes it
happened within a single year, though he says the
evidence in the ice cores is not precise enough
to prove it.

All this comes as a surprise to us because, in
the 10,000 or so years since the end of the last
ice age, the climate has been, relatively
speaking, stable. We have had warm periods and
mini ice ages; but they were little compared with
events before.

It is arguable that this rather benign world has
been the main reason why our species was able to
leave the caves and create the urban, industrial
civilisation we enjoy today. Our complex society
relies on our being able to plant crops and build
cities, knowing that the rains will come and the
cities will not be flooded by incoming tides.
When that certainty fails, as when Hurricane
Katrina hit New Orleans last year, even the most
sophisticated society is brought to its knees.

But there is a growing fear among scientists
that, thanks to man-made climate change, we are
about to return to a world of climatic
turbulence, where tipping points are constantly
crossed. Their research into the workings of the
planet's ecosystems suggests why such sudden
changes have happened in the past, and are likely
again in future.

One driver of fast change in the past has been
abrupt movements of carbon between the atmosphere
and natural reservoirs such as the rainforests
and the oceans. Hundreds of billions of tonnes of
carbon dioxide can burp into the atmosphere,
apparently at the flick of a switch.

That is why the Met Office's warning that the
Amazon rainforest could die by mid-century,
releasing its stored carbon from trees and soils
into the air, is so worrying. And why we should
take serious note when Peter Cox, professor of
climate systems at Exeter University, warns that
the world's soils, which have been soaking up
carbon for centuries, may be close to a tipping
beyond which they will release it all again.

Other threats lurk on the horizon. We know that
there are trillions of tonnes of methane, a
virulent greenhouse gas, trapped in permafrost
and in sediments beneath the ocean bed. There are
fears this methane may start leaking out as
temperatures warm. It seems this happened 55m
years ago, when gradual warming of the atmosphere
penetrated to the ocean depths and unlocked the
methane, which caused a much greater warming that
resulted in the extinction of millions of species.

All this suggests that, in one sense, the climate
sceptics are right. They say the future is much
less certain than the climate models predict.
They have a point. We know less than we think.
But the sceptics are wrong in concluding that the
models have been exaggerating the threat. Far
from it. Evidence emerging in the past five years
or so suggests the presence of many previously
unknown tipping points that could trigger
dangerous climate change.

Can we call a halt? Hansen says we have 10 years
to turn things round and escape disaster. James
Lovelock, author of the Gaia theory, which
considers the Earth a self-regulated living
being, reckons we are already past the point of
no return. I don't buy that.

For one thing, there is no single point of no
return. We have probably passed some, but not
others. The water may be lapping at our ankles,
but I am not ready to head for the hills yet. I'm
an optimist.

=B7 Fred Pearce is author of The Last Generation -
How Nature Will Take Her Revenge for Climate
Change, Eden Project Books, =A312.99. To order a
copy for =A311.99 with free UK p&p call 0870 836
0875 or go to guardian.co.uk/bookshop

Guardian Unlimited =A9 Guardian Newspapers Limited 2006=