Le réchauffement climatique pourrait s'arrêter selon les experts...
Selon des scientifiques, le réchauffement climatique pourrait s'arrêter
jusqu'à au moins 2015 à cause des variations naturelles du climat...
Ne pas rire !
http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/04/30/eaclimate130.xml
<cite>
Global warming may 'stop', scientists predict
By Charles Clover, Environment Editor
Last Updated: 6:01pm BST 30/04/2008
Global warming will stop until at least 2015 because of natural
variations in the climate, scientists have said.
# Have your say: Do you believe in global warming?
# Arctic ice melting 'faster than predicted'
# Weather Channel boss calls global warming 'the greatest scam in history'
Researchers studying long-term changes in sea temperatures said they now
expect a "lull" for up to a decade while natural variations in climate
cancel out the increases caused by man-made greenhouse gas emissions.
Global warming may stop, scientists predict The study predicts the
IPCC's 0.3ºC temperature rise for the next decade may not happen
Melting icebergs: The study predicts the IPCC's 0.3ºC temperature rise
for the next decade may not happen
The average temperature of the sea around Europe and North America is
expected to cool slightly over the decade while the tropical Pacific
remains unchanged.
This would mean that the 0.3°C global average temperature rise which has
been predicted for the next decade by the UN's Intergovernmental Panel
on Climate Change may not happen, according to the paper published in
the scientific journal Nature.
However, the effect of rising fossil fuel emissions will mean that
warming will accelerate again after 2015 when natural trends in the
oceans veer back towards warming, according to the computer model.
Noel Keenlyside of the Leibniz Institute of Marine Sciences, Kiel,
Germany, said: "The IPCC would predict a 0.3°C warming over the next
decade. Our prediction is that there will be no warming until 2015 but
it will pick up after that."
He stressed that the results were just the initial findings from a new
computer model of how the oceans behave over decades and it would be
wholly misleading to infer that global warming, in the sense of the
enhanced greenhouse effect from increased carbon emissions, had gone away.
The IPCC currently does not include in its models actual records of such
events as the strength of the Gulf Stream and the El Nino cyclical
warming event in the Pacific, which are known to have been behind the
warmest year ever recorded in 1998.
Today's paper in Nature tries to simulate the variability of these
events and longer cycles, such as the giant ocean "conveyor belt" known
as the meridional overturning circulation (MOC), which brings warm water
north into the North East Atlantic.
This has a 70 to 80-year cycle and when the circulation is strong, it
creates warmer temperatures in Europe. When it is weak, as it will be
over the next decade, temperatures fall. Scientists think that
variations of this kind could partly explain the cooling of global
average temperatures between the 1940s and 1970s after which
temperatures rose again.
# Global warming forecast predicts rise in 2014
Writing in Nature, the scientists said: "Our results suggest that global
surface temperature may not increase over the next decade, as natural
climate variations in the North Atlantic and tropical Pacific
tem****arily offset the projected anthropogenic [manmade] warming."
The study shows a more pronounced weakening effect than the Met Office's
Hadley Centre, which last year predicted that global warming would slow
until 2009 and pick up after that, with half the years after 2009 being
warmer than the warmest year on record, 1998.
Commenting on the new study, Richard Wood of the Hadley Centre said the
model suggested the weakening of the MOC would have a cooling effect
around the North Atlantic.
"Such a cooling could tem****arily offset the longer-term warming trend
from increasing levels of greenhouse gases in the atmosphere.
"That emphasises once again the need to consider climate variability and
climate change together when making predictions over timescales of
decades."
But he said the use of just sea surface temperatures might not
accurately reflect the state of the MOC, which was several miles deep
and dependent on factors besides temperatures, such as salt content,
which were included in the Met Office Hadley Centre model.
If the model could accurately forecast other variables besides
temperature, such as rainfall, it would be increasingly useful, but
climate predictions for a decade ahead would always be to some extent
uncertain, he added.
</cite>
|
