3-4 Degrees Celsius: Looking Grim
Humans could escape in scenarios where only 10 to 20 percent of
species go extinct. We would likely be reduced in number but
plausibly still do OK at a 30 percent extinction rate.
But as the evidence points toward “up to 50 percent” extinction rate,
we should expect very serious trouble for ourselves.
There has been broad, strong consensus in the climate science
community that we’d better avoid a warming of 2C (2 Celsius) above
today.
Lance
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“We are certainly not on track for a two-degree temperature increase
at the moment. We are much more on track for a three to four-degree
temperature increase and we need to be thinking about what that
actually means.”
“Certainly, if there’s not a good result at Copenhagen, the
two-degree target will look impossible,” he said. “There’s 18 months
of optimism to hold on to. If by Copenhagen it hasn’t been addressed
then it will look very bleak indeed.”
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The Scotsman (Scotland)
Published Date: 01 September 2008
By JENNY HAWORTH
ENVIRONMENT CORRESPONDENT
IT IS “improbable” global warming will be kept below 4C – double the
rise considered safe to avoid climate catastrophe – according to an
influential new report.
Internationally, it has long been agreed governments should be aiming
to keep a global temperature rise below 2C, to avoid climate change
spiralling out of control.
However, a bleak new study by scientists at the Tyndall Centre, a
leading organiation for climate change research at the University of
Manchester, now suggests we should be adjusting our expectations
towards far higher rises.
It warns carbon dioxide in the atmosphere will almost certainly
stabilise at levels of at least 650 parts per million (ppm), which is
roughly equivalent to a four-degree temperature increase.
The authors write: “Given the reluctance, at virtually all levels, to
openly engage with the unprecedented scale of both current emissions
and their associated growth rates, even an optimistic interpretation
of the current framing of climate change implies that stabilisation
much below 650ppm is improbable.”
The authors say even stabilising levels at 650ppm will require
industrialised nations to “begin to make draconian emission
reductions within a decade”.
They argue “planned economic recession” would be needed to keep
climate change at this level, unless a way can be found for economic
growth to go hand in hand with unprecedented rates of reductions in
carbon emissions.
One of the report authors, Dr Alice Bows, agreed the study is
“incredibly worrying”. She added: “We are certainly not on track for
a two-degree temperature increase at the moment. We are much more on
track for a three to four-degree temperature increase and we need to
be thinking about what that actually means.”
According to the 2006 Stern review on the economics of climate
change, a four-degree temperature rise could lead to up to 300
million more people being affected by coastal flooding each year, a
30 to 50 per cent reduction in water availability in Southern Africa,
and up to 50 per cent of animal and plant species facing extinction.
Dr Richard Dixon, director of World Wildlife Fund (WWF) Scotland,
said an increase of more than two degrees could mean a “tipping
point” is reached. “That’s when you get to a runaway situation,” he
said. “The big systems of the world start to go wrong when you get
beyond two degrees.”
However, he thinks the report is at the “bleak” end of the spectrum
and believes there is still reason for optimism, as long as firm
targets are set at the United Nations climate change conference in
Copenhagen next year.
“Certainly, if there’s not a good result at Copenhagen, the
two-degree target will look impossible,” he said. “There’s 18 months
of optimism to hold on to. If by Copenhagen it hasn’t been addressed
then it will look very bleak indeed.”
The report, Reframing the Climate Change Challenge in Light of
Post-2000 Emission Trends, comes as separate research, due to be
published in Nature Geoscience today, will warn that the expected
rise in sea levels due to melting Greenland ice has been seriously
underestimated.
Scientists argue it could be double or triple what is currently
forecast over the next century.
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