Text 16260, 85 rader
Skriven 2007-02-18 22:48:32 av Rich Gauszka (1:379/45)
Ärende: Re: where the hell is my global warming?
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From: "Rich Gauszka" <gauszka@dontspamhotmail.com>


"Geo." <georger@nls.net> wrote in message news:45d91c19$1@w3.nls.net...
 > The permian extinction was caused by global cooling not warming. It was
the
> FREEZE that they think killed off so much life. As I said, warm is more
> life, cold baaaaaad..
>
 > http://park.org/Canada/Museum/extinction/permcause.html
>
> Although the cause of the Permian mass extinction remains a debate,
> numerous theories have been formulated to explain the events of the
> extinction. One of the most current theories for the mass extinction of
> the Permian is an agent that has been also held responsible for the
> Ordovician and Devonian crises, glaciation on Gondwana. A similar
> glaciation event in the Permian would likely produce mass extinction in
> the same manner as previous, that is, by a global widespread cooling
> and/or worldwide lowering of sea level.
>
> Cold=baaaaad...
>
> Geo.

actually new models suggest higher temps

Climate Model Links Higher Temperatures to Prehistoric Extinction

http://www.ucar.edu/news/releases/2005/permian.shtml
August 24, 2005

BOULDER—Scientists at the National Center for Atmospheric Research (NCAR) have
created a computer simulation showing Earth's climate in unprecedented detail
at the time of the greatest mass extinction in the planet's history. The work
gives support to a theory that an abrupt and dramatic rise in atmospheric
levels of carbon dioxide triggered the massive die-off 251 million years ago.
The research appears in the September issue of Geology.

"The results demonstrate how rapidly rising temperatures in the atmosphere can
affect ocean circulation, cutting off oxygen to lower depths and extinguishing
most life," says NCAR scientist Jeffrey Kiehl, the lead author.


Kiehl and coauthor Christine Shields focused on the dramatic events at the end
of the Permian Era, when an estimated 90 to 95% of all marine species, as well
as about 70% of all terrestrial species, became extinct. At the time of the
event, higher-latitude temperatures were

18 to 54 degrees Fahrenheit (10 to 30 degrees Celsius) higher than today, and
extensive volcanic activity had released large amounts of carbon dioxide and
sulfur dioxide into the atmosphere over a 700,000-year period.

To solve the puzzle of how those conditions may have affected climate and life
around the globe, the researchers turned to the Community Climate System Model
(CCSM). One of the world's premier climate research tools, the model can
integrate changes in atmospheric temperatures with ocean temperatures and
currents. Research teams had previously studied the Permian extinction with
more limited computer models that focused on a single component of Earth's
climate system, such as the ocean.

The CCSM indicated that ocean waters warmed significantly at higher latitudes
because of rising atmospheric levels of carbon dioxide (CO2), a greenhouse gas.
The warming reached a depth of about 10,000 feet (4,000 meters), interfering
with the normal circulation process in which colder surface water descends,
taking oxygen and nutrients deep into the ocean.

As a result, ocean waters became stratified with little oxygen, a condition
that proved deadly to marine life. This in turn accelerated the warming, since
marine organisms were no longer removing carbon dioxide from the atmosphere.

"The implication of our study is that elevated CO2 is sufficient to lead to
inhospitable conditions for marine life and excessively high temperatures over
land would contribute to the demise of terrestrial life," the authors concluded
in the article.

The CCSM's simulations showed that ocean circulation was even more stagnant
than previously thought. In addition, the research demonstrated the extent to
which computer models can successfully simulate past climate events. The CCSM
appeared to correctly capture key details of the late Permian, including
increased ocean salinity and sea surface temperatures in the high latitudes
that paleontologists believe were 14 degrees Fahrenheit (8 degrees Celsius)
higher than present.

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