Rapidly Shrinking Arctic Ice Could Spell Trouble for the Rest of the World

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Published on Wednesday, January 11, 2006 by Knight Ridder
Rapidly Shrinking Arctic Ice Could Spell Trouble for the Rest of the World
by Robert S. Boyd

WASHINGTON - Alarmed by an accelerating loss of ice in the Arctic Ocean,
scientists are striving to understand why the speedup is happening and what
it means for humankind.

If present trends continue, as seems likely, the sea surrounding the North
Pole will be completely free of ice in the summertime within the lifetime of
a child born today. The loss could point the way to radical changes in the
Earth's climate and weather systems.

Bright white ice reflects sunlight from the Earth¹s surface. In contrast,
open water is very dark, and absorbs sunlight. As sea ice melts more water
is exposed, which tends to increase warming. (Photograph courtesy NOAA Photo
Library)

Some researchers, such as Ron Lindsay, an Arctic scientist at the University
of Washington in Seattle, fear that the polar region already may have passed
a "tipping point" from which it can't recover in the foreseeable future.
Others, such as Jonathan Overpeck, the director of the Institute for the
Study of Planet Earth at the University of Arizona in Tucson, think the
Arctic ice pack is nearing a point of no return but hasn't reached it yet.
The National Science Foundation, a congressionally chartered agency, last
month announced an urgent research program to determine what "these changes
mean for both the Arctic and the Earth."

"The pace of Arctic change has accelerated," the foundation declared.
"Because of the Arctic's pivotal role in the Earth's climate, it is critical
- perhaps urgent - that we understand this system in light of abundant
evidence that a set of linked and pervasive changes are under way."

The concern has heightened because last summer brought a record low in the
size of the northern ice pack. "The degree of retreat was greater than ever
before," said Ted Scambos, chief scientist at the National Snow and Ice Data
Center in Boulder, Colo. Previous lows were set in 2002, 2003 and 2004.
Since 1980, satellite observations taken each September, the warmest month
of the year in the Arctic, show that the ice cover has been shrinking by an
average of almost 8 percent a year. During that time, the polar ocean lost
540,000 square miles of ice - an area twice the size of Texas, Scambos said.
As a result, ships were able to sail freely, without the usual aid of an
icebreaker, across the northern rim of Siberia last summer. Polar bears and
Inuit natives found it harder to hunt and fish on the dwindling ice.

In addition to covering a smaller area of the ocean, the remaining ice is
getting thinner. Submarine measurements indicate that the central ice pack
thinned by 40 percent from the 1960s to the 1990s, Lindsay reported in the

November issue of the Journal of Climate.

Scientists say the great Arctic thaw will have effects all over the world,
not just in the frozen north. It will magnify the global warming trend
that's been recorded for the last quarter-century. It'll reshape the Earth's
weather systems in unknown ways. It could alter the pattern of ocean
circulation, drastically changing Europe's climate.

"Loss of ice on land is also taking place at an accelerating rate, and this
means sea levels will rise globally," Lindsay said. "Places like New Orleans
will become even less viable."

There are two main reasons for the loss of Arctic sea ice, one external and
one internal.

The external cause is the rise in the Earth's temperature, aggravated by
increased emissions of carbon dioxide and other "greenhouse" gases, which
trap the sun's heat.

Since 1978, the Arctic atmosphere has warmed seven times faster than the
average warming trend in the southern two-thirds of the globe, John Christy,
the director of the Earth System Science Center at the University of Alabama
in Huntsville, reported last week.

Satellite data show that average temperatures over the Arctic spiked upward
by 2.1 degrees Fahrenheit over the past 27 years, Christy said, while
inching up by less than three-tenths of a degree in southern climes.

"I believe the retreat of sea ice in the Arctic is very likely a
manifestation of human-caused global warming," Overpeck said. "Global
temperature increases are accelerating, and so is sea-ice retreat. Humans
are almost certainly the cause of the change in the Arctic."

The internal cause for the loss of sea ice may be even more alarming.
Scientists say the polar ice pack will continue to be in trouble whether or
not global temperatures continue to rise.

"Even if temperatures and conditions went flat from this point forward, we
anticipate that Arctic ice would eventually disappear," Scambos said.
The reason is that ice and snow, like any light-colored surface, reflect
heat from the sun. As the ice shrinks, it leaves more open, darker water to
absorb the sun's heat. More open water slows the formation of fresh ice in
the fall and leads to a still earlier, more extensive melt the following
summer.

"One of the big factors is the increasing melt in summer and the increasing
amount of heat absorbed by the ice-free portions of the Arctic Ocean,"
Lindsay said. It's a "self-reinforcing feedback process."

Last year's record ice loss "provides further evidence that the system is on
a track to this new state," said Jennifer Francis, an Arctic expert at the
Institute of Marine and Coastal Sciences at Rutgers University in Highlands,
N.J.

The worrisome feedback process is almost certain to continue.
"A large group of Arctic system and climate specialists could not find any
natural mechanism that could slow the change," Overpeck said. "To hope for
salvation from Mother Nature is to hope on long odds."
"This is a new world for the Arctic," Scambos said.
© 2006 KR Washington Bureau and wire service sources