[ RadSafe ] RE: extremism (article referencing scientists on global warming effect on Australia)
sandyfl at cox.net
Thu Mar 22 13:25:42 CDT 2007
Interesting article today.
Southern Ocean current faces slowdown threat
By Michael Byrnes
Thu Mar 22, 2:03 AM ET
HOBART (Reuters) - The impact of global warming on the vast Southern Ocean
around Antarctica is starting to pose a threat to ocean currents that
distribute heat around the world, Australian scientists say, citing new
Melting ice-sheets and glaciers in Antarctica are releasing fresh water,
interfering with the formation of dense "bottom water," which sinks 4-5
kilometers to the ocean floor and helps drive the world's ocean circulation
A slowdown in the system known as "overturning circulation" would affect the
way the ocean, which absorbs 85 percent of atmospheric heat, carries heat
around the globe.
"If the water gets fresh enough ... then it won't matter how much ice we
form, we won't be able to make this water cold and salty enough to sink,"
said Steve Rintoul, a senior scientist at the Australian government-funded
CSIRO Marine Science.
"Changes would be felt ... around the globe," said Rintoul, who recently led
a multinational team of scientists on an expedition to sample deep-basin
water south of Western Australia to the Antarctic.
Water dense enough to sink to the ocean floor is formed in polar regions by
surface water freezing, which concentrates salt in very cold water beneath
the ice. The dense water then sinks.
Only a few places around Antarctica and in the northern Atlantic create
water dense enough to sink to the ocean floor, making Antarctic "bottom
water" crucial to global ocean currents.
But the freshening of Antarctic deep water was a sign that the "overturning
circulation" system in the world's oceans might be slowing down, Rintoul
said, and similar trends are occurring in the North Atlantic.
For the so-called Atlantic Conveyor, the surface warm water current meets
the Greenland ice sheet then cools and sinks, heading south again and
driving the conveyor belt process.
But researchers fear increased melting of the Greenland ice sheet risks
disrupting the conveyor. If it stops, temperatures in northern Europe would
Rintoul, who has led teams tracking water density around the Antarctic
through decades of readings, said his findings add to concerns about a
"strangling" of the Southern Ocean by greenhouse gases and global warming.
Australian scientists warned last month that waters surrounding Antarctica
were also becoming more acidic as they absorbed more carbon dioxide produced
by nations burning fossil fuels.
Acidification of the ocean is affecting the ability of plankton --
microscopic marine plants, animals and bacteria -- to absorb carbon dioxide,
reducing the ocean's ability to sink greenhouse gases to the bottom of the
Rintoul said that global warming was also changing wind patterns in the
Antarctic region, drawing them south away from the Australian mainland and
causing declining rainfall in western and possibly eastern coastal areas.
This was contributing to drought in Australia, one of the world's top
agricultural producers, he said.
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From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf
Of Johansen, Kjell
Sent: Thursday, March 22, 2007 10:51 AM
To: radsafe at radlab.nl
Subject: [ RadSafe ] RE: extremism
Therefore, I conclude that the extremist position is the one taken by
the person who sits around wanting more conclusive proof before taking
any action to lower the consequences of global climate change.
Whitefish Bay, WI
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