RE: [asa] Arctic sea ice and global warming

Don,
 
There is something of a reverse feeback loop here with the melting of arctic ice, but it has more to do with salinity than with temperature. The north Atlantic is an important point in the global ocean coveyer belt circulation system. Near surface currents bring warm water up from the south to this point. These waters then cool, and due to the higher density of cool water (at least until 4 C), they sink in the north Atlantic and then return to southerly lattitudes as deeper water currents. The melting arctic ice causes an influx of fresh water into the North Atlantic. These fresh waters are less dense than saline ocean water, so the sinking phenomenon can be "shut off", in a sense, causing a break in the global ocean circulation. This has the effect of causing colder tempertures, especially across Europe. It is believed by many that this phenomenon is what lead to the "Little Ice Age" that hit Europe between ~1500-1850 AD. So yes, there is something of a reverse feedback loop here with the melting of ice causing colder T, and therefore more ice. However, I think most climate scientists would argue that the warming induced during the 20th century is more than enough to overcome this effect and continue the warming trend.
 
The History Channel had a very interesting program recently on "The Little Ice Age: Big Chill" that discussed the science behind this period of climate change and the massive cultural effects it had on Western Civilization. It was the best 2 hours I spent in front of the TV in 2006, and I highly recommend catching it if they air it again.
http://store.aetv.com/html/product/index.jhtml?id=74653
 
Best,
Charles

 
_______________________________
Charles W. Carrigan, Ph.D.
Assistant Professor of Geology
Olivet Nazarene Univ., Dept. of Physical Sciences
One University Ave.
Bourbonnais, IL 60914
PH: (815) 939-5346
FX: (815) 939-5071
ccarriga@olivet.edu
http://geology.olivet.edu/
 
"To a naturalist nothing is indifferent;
the humble moss that creeps upon the stone
is equally interesting as the lofty pine which so beautifully adorns the valley or the mountain:
but to a naturalist who is reading in the face of the rocks the annals of a former world,
the mossy covering which obstructs his view,
and renders indistinguishable the different species of stone,
is no less than a serious subject of regret."
          - James Hutton
_______________________________

>>> "Don Perrett" <donperrett@theology-perspectives.net> 1/8/2007 11:25:07 AM >>>
I'm curious, if the fresh water ice at the poles melts and lowers the
salinity of the oceans, will this not cool the oceans and thereby help to
reduce global temps?

Don

-----Original Message-----
From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu] On
Behalf Of PvM
Sent: Monday, January 08, 2007 11:49 AM
To: Janice Matchett
Cc: ASA
Subject: Re: [asa] Arctic sea ice and global warming

Janice's "argument" is once again one of fallacy. The reason polar bears are
thriving since the 1970's is because of hunting agreements.
However, the fact that their habitats are being destroyed is a real
phenomenon.

Then again, the 'happy polar bears' at Seaworld are an indication that such
animals can thrive anywhere. ROTFL The level of logic here is just baffling.
Is this the level of arguments we should expect against those concerned
about the environment?
So what about the declining polar extents Janice? Does that not concern you?

On 1/7/07, Janice Matchett <janmatch@earthlink.net> wrote:
>
> At 12:04 AM 1/8/2007, PvM wrote:
>
>
> Including 2006, the September rate of sea ice decline is now
> approximately -8.59% per decade, or 60,421 km2/year (23,328 mi2/year.
> NSIDC Research Scientist Julienne Stroeve said, "At this rate, the
> Arctic Ocean will have no ice in September by the year 2060." The loss
> of summer sea ice does not bode well for species like the polar bear,
> which depend on the ice for their livelihood, she said.
>
> But then again, the polar bear was never mentioned in the Bible so
> why should we care P-) ..." ~ Pim @ Good news is mentioned in the
> Bible. (So is the one who personifies "bad
> news") :)
>
>

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Received on Mon Jan 8 12:53:09 2007