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tACKliNg CliMAte ChANge:
New Scientific Findings describe
Accelerating Climate Change
Meanwhile, skeptics continue to distort the data.
By CHUCK KUTSCHER
Chuck Kutscher is a
principal engineer and
manager of the thermal
systems group at the
National renewable
energy laboratory.
he is a past Ases chair
and was chair of the
solAr 2006 conference, which resulted in
the Ases report, “
tackling Climate Change in
the u.s.” (Free download at ases.org/
climatechange.) he
teaches a course at
the university of Colorado entitled “Climate
Change solutions.”
The opinions expressed
here are solely those of
the author.
The climate change skeptics have been busier than
ever misrepresenting data to argue that global
warming has ceased, or even reversed. On Feb.
15, a Washington Post column by George Will stated,
among other things, that “global levels of sea ice” were
unchanged from 1979. Many have pointed out the deceptions in Will’s arguments. For example, he confused global
sea ice measured on Dec. 31 with summer Arctic sea ice,
which scientists consider a far more appropriate indicator
of global warming.
For the average non-scientist, it doesn’t help reinforce
the case for global warming that the world average surface air temperature for 2008 was the lowest since 2000
(although a one-year temperature reading doesn’t mean
much, and 2008 was still the ninth-warmest year since measurements began in 1880). The drop in 2008 reflected the
fact that El Niño and La Niña cycles overlay the long-term
warming trend, and 2008 experienced a persistent La Niña,
resulting in cool Pacific surface waters. Absent a major
volcanic eruption, there is a good chance that the next El
Niño will bring a new world average temperature record.
Reading papers in peer-reviewed journals like Science,
Nature and Nature Geoscience is one way to keep abreast
of the real science, but journal articles spend a long time
in review, and I like to get a sense of what is coming down
the pike. So for the past several years, I have made a point
of attending climate change sessions at the annual meeting of the American Association for the Advancement
of Science (AAAS), where scientists discuss their latest
findings. At the February meeting in Chicago, I found that
scientists are now more concerned than ever.
An especially interesting session was entitled “What Is
New and Surprising Since the IPCC Fourth Assessment?”
It’s been two years since the Intergovernmental Panel on
Climate Change released its Fourth Assessment Report
( ipcc.ch/ipccreports/assessments-reports.htm), and the
common feeling among scientists is that it was too conservative. Chris Field of Stanford University showed that
with all the recent economic growth and coal burning
in China and India, the world has been emitting more
carbon dioxide than the worst-case scenario envisioned
14 May 2009 SOLAR TODAY
solartoday.org
by the IPCC back in 2000. The worldwide recession may
bring some temporary improvement here, but economic
hardship hardly seems an attractive long-term prescription for global warming.
Field noted two dangerous feedbacks that will exacerbate climate change. First, drying forests will result in
increased wildfires (as we are already witnessing), replacing carbon sinks with carbon sources. Second, melting
permafrost in Siberia can potentially release enormous
amounts of carbon, and 30 percent of that carbon is in the
form of methane, which has 25 times the global warming
potential of carbon dioxide.
Peter Lemke of the Alfred Wegener Institute for Polar
and Marine Research in Potsdam, Germany, described the
continued warming in the Arctic. After the very large drop
in the extent of summer Arctic sea ice in 2007, there was a
slight recovery in 2008. But, unlike 2007, the summer sea
ice in 2008 was mostly one-year ice, which is roughly half
the thickness of multi-year ice. The total mass of summer
Arctic sea ice continues its long-term downward trend.
Land-based ice, whose melting contributes directly
to sea level rise, is not faring much better than summer
Arctic sea ice. Several studies since the last IPCC report
have shown that the total surface melt area in Greenland
has expanded. In east Antarctica, warmer air that can hold
additional moisture is depositing more snow. But recent
studies indicate that, as a result of warming in west Antarctica, Antarctica as a whole is also experiencing a net
loss of ice mass.
Anny Cazenave of the Centre National d’Etudes Spa-tiales in Toulouse, France, discussed a study of the latest satellite data on sea level rise. The last IPCC report
attributed about half the sea level rise to melting land ice
and half to thermal expansion of the oceans. Cazenave
concludes that between 2003 and 2008, only about 20
percent of the sea level rise was due to thermal expansion,
and nearly 80 percent was due to the melting of the polar
ice sheets and mountain glaciers. This melting of land-based ice is what has caused James Hansen and other
scientists to warn that sea level rise by 2100 may greatly
exceed IPCC projections.
