Archives of Past
Articles for Chapter 7
2008 September
1. Thawing
permafrost likely to boost global
warming. Eureka
Alert. Excerpt: The thawing of
permafrost in northern latitudes,
which greatly increases microbial
decomposition of carbon compounds
in soil, will dominate other effects
of warming in the region and could
become a major force promoting
the release of carbon dioxide and
thus further warming, according
to a new assessment in the September
2008 issue of BioScience. The study,
by Edward A. G. Schuur of the University
of Florida and an international
team of coauthors, more than doubles
previous estimates of the amount
of carbon stored in the permafrost:
the new figure is equivalent to
twice the total amount of atmospheric
carbon dioxide....
Schuur and his colleagues...judge
that over millennia, soil processes
have buried and frozen over a trillion
metric tons of organic compounds
in the world's vast permafrost
regions. The relatively rapid warming
now under way is bringing the organic
material back into the ecosystem,
in part by turning over soil....
Schuur and his colleagues acknowledge
many difficulties in estimating
carbon dioxide emissions from permafrost
regions.... Data
are limited, and emissions are
influenced by the amount of surface
water, topography, wildfires, snow
cover, and other factors. Thawing,
although believed to be critical,
is hard to model accurately.
Some warming-related trends in
Arctic regions, such as the encroachment
of trees into tundra, may cause
absorption of carbon dioxide and
thus partly counter the effects
of thawing permafrost. But Schuur
and colleagues' new assessment
indicates that thawing is likely
to dominate known countervailing
trends....
2008 July 3.
Plasma,
LCDs blamed for accelerating global
warming. ABC News.
Excerpt:
A gas used in the making of flat
screen televisions, nitrogen trifluoride
(NF3), is being blamed for damaging
the atmosphere and accelerating
global warming.
Almost half of the televisions
sold around the globe so far this
year have been plasma or LCD TVs.
...The gas, widely used in the
manufacture of flat screen TVs,
is estimated to be 17,000 times
as powerful as carbon dioxide.
Ironically, NF3 is not covered
by the Kyoto protocol as it was
only produced in tiny amounts when
the treaty was signed in 1997.
Levels of this gas in the atmosphere
have not been measured, but scientists
say it is a concern and are calling
for it to be included in any future
emissions cutting agreement.
Professor Michael Prather from
the University of California has
highlighted the issue in an article
for the magazine New Scientist.
...He estimates 4,000 tons of NF3
will be produced in 2008 and that
number is likely to double next
year.
...Dr Paul Fraser is the chief
research scientist at the CSIRO's
marine and atmospheric research
centre, and an IPCC author.
He says without measuring the quantity
of NF3 in the atmosphere it is
unclear what impact it will have
on the climate.
"We haven't observed it in
the atmosphere. It's probably there
in very low concentrations," he
said.
"The key to whether it's a
problem or not is how much is released
to the atmosphere."
16 February 2007. PHYTOPLANKTON
AID IN GREENHOUSE GAS CONTROL - This
broadcast of Earth & Sky
radio show featured NASA Earth
science. The show is also available
to download as an audio Podcast.
February 2006. From
Carbon Cycles to Climate Models.
By David Pescovitz. ScienceMatters@Berkeley
Volume 3, Issue 18. ...
UC Berkeley
professor Inez Fung constructs
incredibly complex computer simulations
of the climate. ..."There's
a rogues gallery of these atmospheric
species, greenhouse gases like
carbon dioxide and methane, that
affect the energy cycle and climate," says
Fung, co-director of the new Berkeley
Institute of the Environment and
former director of the Berkeley
Atmospheric Sciences Center. "I'm
hitting them one-by-one to understand
what determines their concentration
in the atmosphere, why that's
changing, and how."
...Most famously, Fung and her
colleagues modeled the carbon
cycle, how carbon dioxide moves
in and out of the atmosphere.
Previous calculations included
the fact that humans burning fossil
fuel at a certain rate will boost
carbon dioxide levels in the atmosphere.
[see graphic depiction of the
Earth's carbon cycle, highlighting
various sources and sinks for carbon.]
...Fung studies the whole shebang.
...trees are much more involved
in carbon uptake and atmospheric
cooling than previously believed.
A study in the Amazonian forest
showed that the roots shift water
deep in the ground in such a way
that they "pull
more carbon dioxide from the atmosphere
as they conduct more photosynthesis" even
during the dry season, Dawson
says. The trouble is that there's
a limit to how much carbon dioxide
the world's plants can handle.
Right now, plants and oceans absorb
about half of the CO2 that's generated
from the burning of fossil fuels.
Last year, Fung's climate model
indicated that in the next fifty
years or so, the "breathing
biosphere" may be overwhelmed.
...And after plants die, their
decomposition by microbes in the
soil also play a part in the carbon
cycle. "If you don't look
at decomposition, it's like looking
at your income without considering
your expenses," Fung says. "You
have to think about the whole
life cycle across the entire
biosphere." Simultaneously,
the oceans' capabilities as a CO2
sink are hampered....
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