IPCC Understates Case for Man-Made Warming: Study
Review says global warming is man-made
The Financial Times, March 4, 2010
The case
for man-made global warming is even stronger than the Intergovernmental
Panel on Climate Change maintained in its official assessments,
according to the first scientific review published since December’s
Copenhagen conference and subsequent attacks on the IPCC’s credibility.
An
international research team led by the UK Met Office spent the past
year analysing more than 100 recent scientific papers to update the
last IPCC assessment, released in 2007.
Although
the review itself preceded the sceptics’ assault on climate science
over the past three months, its launch in London on Thursday marks a
resumption of the campaign by mainstream scientists to show that
man-made releases of greenhouse gases are causing potentially dangerous
global warming.
“The
fingerprint of human influence has been detected in many different
aspects of observed climate changes,” said Peter Stott, head of climate
monitoring at the Met Office Hadley Centre for Climate Research.
“Natural variability, from the sun, volcanic eruptions or natural
cycles, cannot explain recent warming.”
The
review, published in the journal Wiley Interdisciplinary Reviews:
Climate Change, found several “fingerprints” of warming that had not
been established by the time of the last IPCC assessment but were now
unambiguously present.
One is human-induced climate in the Antarctic, the last continent where regional warming has been demonstrated.
There is
also new evidence of warming in the oceans, which is having several
effects. The subtropical Atlantic is becoming saltier; the extra
salinity could in turn alter ocean currents.
Another
effect of ocean warming is increasing evaporation, leading to more
humidity in the atmosphere and changing rainfall patterns.
“The
whole water cycle is changing,” said Mr. Stott. “The wet regions are
tending to get wetter and the dry regions are getting dryer.”
Globally,
this means less rainfall in the tropics and more at higher latitudes,
although Mr. Stott said there was much regional variation in the
pattern, which scientists were still working to make sense of.
The
review is based on a forensic comparison of the pattern of changes
expected from man-made warming with those that would result from other
factors such as changing solar radiation and purely natural variations.
A
separate study by Russian and US scientists, published today in the
journal Science, shows that methane, a powerful greenhouse gas, is
escaping from the seafloor of the warming Arctic Ocean more rapidly
than had been suspected.
Copyright The Financial Times Limited 2010
