Climate Change News
– September
15,
2006
Brought to you by the
Environmental and Energy Study Institute
Carol Werner, Executive Director
Arctic Sees Rapid Loss
of Winter Sea Ice
On September 13, NASA released
three reports showing that Arctic perennial sea ice, which
normally survives the summer melt season and remains
year-round, shrunk abruptly by 14 percent between 2004 and
2005. This compares to a loss of merely 1.5 percent per
decade on average annually since the earliest satellite
monitoring in 1979. This is happening as summer sea ice
continues its retreat at an average of 10
percent per decade.
As reported by NASA, the overall
decrease in winter Arctic perennial sea ice totals 280,000
square miles--an area the size of Texas. Perennial ice can
be 10 or more feet thick. The lost perennial ice is being
replaced by new, seasonal ice only about one to seven feet
thick that is more vulnerable to summer melt. The research
indicates that winds pushed perennial ice from the East to
the West Arctic Ocean, where it then moved into warmer
waters to eventually melt.
A team led by Dr. Son Nghiem of
NASA's Jet Propulsion Laboratory, Pasadena, Calif., used
NASA's QuikScat satellite to measure the extent and
distribution of perennial and seasonal sea ice in the
Arctic. Dr. Nghiem said, "Recent changes in Arctic sea
ice are rapid and dramatic.... If the seasonal ice in the
East Arctic Ocean were to be removed by summer melt, a vast
ice-free area would open up. Such an ice-free area would
have profound impacts on the environment, as well as on
marine transportation and commerce." If the sea ice
cover continues to decline, the surrounding ocean will get
warmer, further accelerating summer ice melts and impeding
fall freeze-ups. This longer melt season will, in turn,
further diminish the Arctic ice cover.
Dr. Nghiem's study results are
published in the September 7 issue of Geophysical
Research Letters.
Polar Bears Threatened by Reduced Arctic Ice Pack
Polar bears depend on sea ice
for survival. On September 13, NASA and the Canadian
Wildlife Service published a report in the September issue
of the journal Arctic showing that since the 1970s,
sea ice cover in prime hunting areas for some Canadian polar
bears has been breaking up earlier and earlier each summer,
forcing the animals onto land and closer to native villages
an average of three weeks sooner. Inuit hunters in the areas
of four polar bear populations in the eastern Canadian
Arctic have reported seeing more bears near settlements
during the open-water period in recent years.
Claire Parkinson, a NASA
scientist and co-author of the report, said "Our
research strongly suggests that climate warming is having a
significant and negative effect on a primary species reliant
on the sea ice for survival.... Our concern is that if the
length of the sea ice season continues to decrease, polar
bears will have shorter periods on the ice to feed."
The researchers' data also indicate the likelihood
that progressively earlier breakup of the sea ice was likely
to also cause reproductive problems for polar bears. Ian
Stirling, a research scientist specializing in polar marine
mammals with the Canadian Wildlife Service,
said "In 1980 the average weight of adult
females in western Hudson Bay was 650 pounds. Their average
weight in 2004 was just 507 pounds – a 143-pound reduction."
A 1992 study in the Canadian Journal of Zoology
indicated that no females weighing less than 416 pounds gave
birth the following spring.
Satellite imagery shows climate
warming in the Arctic has caused significant declines in
total cover and thickness of sea ice in the polar basin and
progressively earlier breakup in some areas, so that bears
must fast for longer periods during the open-water season.
The report finds that polar bears will be increasingly
food-stressed, and their numbers are likely to decline
eventually, probably significantly so.
Recently declassified data from
the Soviet and U.S. navies shows the thickness of the
perennial ice over the Arctic has declined from about 11
feet in the early 1960s to 7 feet or less today. While ice
does form over the remaining open water during the winter,
that seasonal ice is only about 1 to 5 or 6 feet thick, and
breaks up quickly.
Top NASA Scientist Says 10 Years Left to Avoid
Dangerous Climate Change
On September 13, speaking at the
Third Annual Climate Change Research Conference in
Sacramento, California, Dr. James Hansen, NASA's top climate
scientist and Director of NASA's Goddard Institute for Space
Studies, said “I think we have a very brief window of
opportunity to deal with climate change ... no longer than a
decade, at the most." If the world continues with a
“business as usual” scenario, Dr. Hansen said
temperatures will rise by 2-3°C (3.6-7.2°F) and “we will
be producing a different planet.”
Dr. Hansen said, “We cannot
burn off all the fossil fuels that are readily available
without causing dramatic climate change.... This is not
something that is a theory. We understand the carbon cycle
well enough to say that.” He praised California for taking
the “courageous” step of passing legislation on global
warming last month that will make it the first U.S. state to
place caps on greenhouse gas emissions.
With regard to the just-released
NASA reports on Arctic sea ice loss and effects on polar
bears, Dr. Hansen said, “It is not too late to save the
Arctic, but it requires that we begin to slow carbon dioxide
emissions this decade." Dr. Hansen offered this
prescription for moderating global warming: limit the use of
coal to power plants that capture and sequester their carbon
dioxide exhaust; and,
adopt a carbon tax that rises gradually to discourage the
use of fossil fuels and to encourage the development of
alternatives. More than 300 people from science and
environment circles attended the state-sponsored
conference.
Study Links Tropical Ocean Warming to Greenhouse
Gases
A study published online in the
September 12 issue of the Proceedings of the National
Academy of Sciences (PNAS) finds that observed sea
surface temperature (SST) increases in the Atlantic and
Pacific tropical cyclone generating regions range from
0.32-0.67°C (0.6-1.2°F) over the 20th century. The 22
climate models examined in the study suggest that such
century-timescale SST changes of this magnitude cannot be
explained solely by unforced variability of the climate
system. For the period 1906-2005, the study found an 84
percent chance that external (human-caused) climate forcing
explains at least two-thirds of observed SST increases in
the two tropical cyclone generating regions.
The lead author of the study,
Dr. Benjamin Santer of the Lawrence Livermore National
Laboratory, said the findings suggested that further warming
would probably make hurricanes stronger in coming decades.
As reported by the New York Times, several climate
experts said that while debate persisted about the role of
warming in pumping up hurricanes, there was little doubt
about the long-term trend should warming continue as
projected. Dr. Santer said, “Even under modest scenarios
for emissions, we’re talking about sea surface temperature
changes in these regions of a couple of degrees.... That’s
much larger than anything we’ve already experienced, and
that is worrying.”
Changes in Solar Output Do
Not Drive Climate Change
Some climate skeptics look to
small variations in the Sun's power output, or luminosity,
to explain some of the Earth's observed climate change. A
study published in the September 14 issue of Nature
finds that changes in the sun's output over the last 30
years, a period of significant global warming, cannot be
explained by variations in the solar luminosity.
Since 1978 it has been possible
to track dark (sunspot) and bright (faculae) structures on
the solar disk accurately with satellites. The data show a
variation of only 0.07 percent since 1978. Solar astronomer
Peter Foukal of Heliophysics, Inc., in Nahant, Massachusetts
and coauthors conclude that, based on satellite and isotope
data, solar brightening is unlikely to have had a
significant effect on climate change since the seventeenth
century.
Co-author Tom Wigley of the
National Center for Atmospheric Research (NCAR) said, “Our
results imply that, over the past century, climate change
due to human influences must far outweigh the effects of
changes in the Sun's brightness." More speculative
climate changes related to the Sun's ultraviolet light and
magnetized plasma output are not yet ruled out, but are hard
to quantify due to the complex interactions involved.
Europe, Asia Adopt Declaration on Climate Change
On September 11, European and
Asian leaders met in Helsinki, Finland, at their bi-yearly
Asia-Europe Summit (ASEM) to discuss what to do about
stemming greenhouse gas (GHG) emissions after the Kyoto
Protocol on Climate Change expires in 2012. While stopping
short of setting new targets beyond the Kyoto agreement, the
leaders did agree to keep reducing GHG emissions after the
Kyoto Protocol expires.
In the joint ASEM 6 Declaration
on Climate Change Helsinki, the ASEM countries--composed of
25 European Union members and 13 Asian countries--stated,
"The global nature of climate change calls for the
widest possible cooperation and participation in an
effective and appropriate international response.... We will
cooperate to further implement the [UNFCCC] Convention and
its Protocol including through strengthening the capacity of
and providing financial and technical assistance to ASEM
developing countries." The declaration notes that ASEM
countries, by 2030, would have invested some $6.3 trillion
in the energy sector.
The leaders stated that energy
security and climate change are interrelated, and called for
international cooperation to promote development, transfer
and deployment of low carbon technology, including energy
efficiency and new and renewable energy. German Chancellor
Angela Merkel said, "In comparison to 10 years ago, now
all countries recognize that climate change is an important
issue, that we must continue Kyoto, that the time after 2012
must be in our sights and that we must do everything
possible to improve energy efficiency and, at the same time,
facilitate economic growth."
