http://www.nytimes.com/2007/01/29/science/29cnd-heat.html
Scientists Gather to Finalize Climate Report
By JAMES KANTER and ANDREW C. REVKIN
Published: January 29, 2007
PARIS, Jan 29 Scientists from across the world
gathered here today to hammer out the final
details of an authoritative report on climate
change that is expected to project centuries of
rising temperatures and sea levels unless curbs
are placed on emissions of carbon dioxide and
other gases that trap heat in the atmosphere.
According to scientists involved with writing or
reviewing the report, the fourth since 1990 from
the Intergovernmental Panel on Climate Change, a
body overseen by the United Nations, it is nearly
certain to conclude that there is at least a 90
percent probability that human-caused emissions
are the main driver of warming since 1950.
The report, according to several authors, who
spoke only on condition of anonymity saying that
details could still change, will describe a
growing body of evidence showing that warming is
likely to profoundly transform the planet.
Three large sections of the report will be
forthcoming during the year, with the summary for
policymakers and sections on basic climate science coming on Friday.
Among findings in recent drafts are that the
Arctic Ocean could largely be devoid of sea ice
in summers later in the century; the Alps could
shift from snowy winter destinations to summer
havens from the heat; growing seasons in
temperate regions will expand, while droughts
will likely further ravage semi-arid regions of Africa and southern Asia.
"Concerns about climate change and public
awareness on the subject are at an all time
high," the chairman of the IPCC, Rajendra Pachauri, told delegates today.
"It would perhaps be no exaggeration to suggest
that at no time in the past has there been a
greater global appetite for knowledge on any
subject as there is today on the scientific facts
underlying the reality of global climate change," Dr. Pachauri said.
But scientists involved in the effort warned that
squabbling between teams and representatives from
governments of more than 100 countries over how
to portray the most probable amount of sea-level
rise during the 21st century could distract from
the basic finding that a warming world will be
one in which retreating coasts are the new normal for centuries to come.
Jerry Mahlman, an emeritus researcher at the
National Center For Atmospheric Research in
Boulder, Colo., who was a reviewer of the
reports single-spaced, 1,644-page summary of
climate science, said that most of the leaks to
the press so far were from people eager to find
elements that were the scariest or most reassuring.
He added in an interview yesterday that such
efforts distract from the basic, undisputed
findings, saying that those point to trends that are very disturbing.
Mr. Mahlman pointed to recent disclosures that
there is still uncertainty about the pace at
which seas will rise due to warming and melting
of terrestrial ice over the next 100 years. That
span, he said, was just the start of a process of
a rise in sea levels that would then almost
certainly continue for 1,000 years or so.
The latest draft of the IPCC summary highlights
the hazardous consequences of business as
usual, finding that twice the pre-industrial
concentration of carbon dioxide in the atmosphere
will likely warm the climate by between 3.5
degrees and 8 degrees Fahrenheit, with a greater
than one-in-ten chance of much higher temperatures.
Even the mid-range projection for warming,
according to many climate experts and biologists,
is likely to powerfully stress ecosystems and
disrupt longstanding climate patterns related to
water supplies and agriculture.
Many economists and energy experts long ago
abandoned any expectation that it would be
possible to avoid a doubling of pre-industrial
carbon dioxide concentrations given growth of
human populations, use of fossil fuels,
particularly coal, and deforestation in the tropics.
As a result, a significant focus of the summary
coming this week and of other sections of the
report will be the necessity to boost the
resilience of agriculture and water supplies to
inevitable shifts, while trying to slow and, as
soon as it can be affordably done, reverse the
century-long climb in releases of the heat-trapping gases.
Many experts involved in the IPCC process said
there is hope that with a prompt start on slowing
emissions, the chances of seeing much great
warmer and widespread disruption of ecosystems and societies can be cut.
Outside experts agreed.
``We basically have three choices - mitigation,
adaptation, and suffering, said John Holdren,
the president of the American Association for the
Advancement of Science and an energy and climate
expert at Harvard University. ``Were going to do
some of each. The question is what the mix is
going to be. The more mitigation we do, the less
adaptation will be required and the less suffering there will be.
One key point of controversy in early drafts of
the IPCC report is a smaller rise in sea level
than the last report projected. In the next
several days, scientists relying on field
observations and computer models of ocean and ice
behavior in a warming world will struggle to find a consensus.
Some scientists say that the figures used in the
upcoming report are not up to date because they
leave out recent observations of instability in
some ice sheets in Antarctica and Greenland.
Ice loss in those regions has been very sudden in
some cases, implying a more rapid rise in sea
levels than projected by some computer models.
Another possible point of contention during the
four days of closed-door sessions in Paris this
week could be assertions in early drafts of the
report that the recent warming rate was blunted
by particle pollution and volcanic eruptions.
Some scientists say the final report should
reflect the assumption that the rate of warming
in coming years is likely to be more pronounced that in previous decades.
The IPCC report will not outline measures to
tackle global warming. Instead, it will
concentrate on the latest evidence that the phenomenon is underway.
But Achim Steiner, the executive director of the
United Nations Environment Programme, said the
findings that will be presented on Friday should
lead decision-makers to accelerate efforts to
slash carbon emissions and to help people in
vulnerable parts of the world prepare for climate change.
"These findings should strengthen the resolve of
governments to act now to reduce greenhouse gas
emissions and put in place the medium to longer
term strategies necessary to avert dangerous climate change," said Mr. Steiner.
In a new report issued on today, UNEP said the
most recent evidence from mountain glaciers
showed they were melting faster than before, or
1.6 times more than the average of the 1990s, and
three times the loss rate of the 1980s.
UNEP warned that the trend was likely to continue
because 2006 was one of the warmest years in many parts of the world.
Also today, there were new concerns about climate
change in low-lying parts of the world. Indonesia
could lose about 2,000 islands by 2030 because of
the phenomenon, according to the countrys
environment minister, Rachmat Witoelar.
Over the past year, international concern over
what to do about global warming has grown along
with concrete signs of climate change in
developing regions like Africa, where water is
running low, and in developed regions, like
Europe, where there was a marked lack of snow at
Alpine ski resorts during early January.
Even so political leaders are still groping for
ways to tackle the phenomenon. Europe has adopted
a program that caps the amount of emissions from industrial producers.
But the worlds largest emitter, the United
States, still is debating whether to adopt a
similar policy while developing-world countries
like China are resisting caps on the grounds that
the industrialized world contributed about 75
percent of the current volume of greenhouse gases
and should make the deepest cuts.
That has hampered the chances of an effective
solution, which experts say will require all
nations to cut emissions or become more energy efficient.
The second section of the IPCC report, which
focuses on the impacts of and ways of adapting to
climate change, is slated for release in April,
while a section on mitigating climate change is expected to be released in May.
The final part, a synthesis of all three parts
for policy-makers, is expected in November.
Andrew C. Revkin reported from New York
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((Udhay Shankar N)) ((udhay @ pobox.com)) ((www.digeratus.com))
