Thursday, February 17, 2005 by Agence
Dramatic Changes in Southern Ocean, Fear Climate Link
HOBART, AUSTRALIA -
Scientists have discovered dramatic changes in the temperature
and salinity of deep waters in the Southern Ocean that they warn
could have a major impact on global climate.
Steve Rintoul of Australia said his multinational team of
researchers had found that waters at the bottom of the Southern
Ocean were significantly cooler and less salty than they were 10
The Earth from space.
discovered a rapid change in the temperature and
salinity of deep waters in the Southern Ocean that could
have a major impact on global climate (AFP/NASA)
He said the size and speed of the changes surprised scientists,
who have long believed deep ocean waters underwent little
temperature change, and could indicate a slowdown in the flow of
deep water currents.
"Ocean circulation is a big influence on
global climate, so it is critical that we understand why this is
happening and why it is happening so quickly," Rintoul said
after he and his team docked at Hobart on the Australian island
state of Tasmania.
"The surprise was just how rapidly the
deepest parts of the ocean are changing, at depths of four or
five kilometers (13,200-16,500 feet) below the sea surface,"
"Whether its a
natural cycle that takes place over many decades, or it's
climate change, it's an indication that the deep ocean can
respond much more rapidly to changes that are happening near the
surface than we believed possible," he said.
sampled 3,000 kilometers of the Southern Ocean basin during an
eight-week expedition aboard the Australian Antarctic Division's
research ship Aurora Australis.
Their findings added
new urgency to the study of climate change, Rintoul said.
indication that the climate is capable of changing and is
changing now," he said.
"What we need
to do is sort out if this is human-induced change and if so, how
rapidly is the climate going to change and what will the impacts
of that change be?" he said.
The new findings
emerged a day after the UN's Kyoto Protocol on climate change
came into force. The treaty aims to cut production of so-called
greenhouse gases believed responsible for a warming of the
expedition, the Australian-led team released 19 free-floating
ocean robots known as Argo floats, which are designed to drift
with ocean currents to better measure temperature and salinity.
The floats, part of
an international ocean-monitoring effort, drift about 2,000
meters (6,600 feet) underwater and surface every 10 days to
Rintoul said the
Argos would provide a huge boost to climate research.
revolutionize how we understand the ocean, in particular to
determining climate change and shorter climate cycles," he
"One of the
real challenges for us when we try to answer the question of 'is
this climate change?' is that we only have measurements from a
few southern snapshots," he said.
measured it continuously in time so it's hard for us to tell the
difference between a cycle, something moving up and down, and a
long-term trend. That's the real challenge."
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