November 17, 2006 — By Randolph E. Schmid, Associated Press
WASHINGTON — Signs of warming continue
in the Arctic with a decline in sea ice, an increase in shrubs growing on
the tundra and rising concerns about the Greenland ice sheet.
"There have been regional warming periods before. Now we're seeing
Arctic-wide changes," James Overland, an oceanographer at the Pacific
Marine Environmental Laboratory in Seattle, said Thursday.
For the past five years, it was at least 1.8 degrees Fahrenheit above
average over the Arctic over the entire year, he said.
The new "State of the Arctic" analysis, released by the National Oceanic
and Atmospheric Administration, also reports an increase in northward
movement of warmer water through the Bering Strait in 2001-2004. This may
have contributed to a continuing reduction of sea ice.
During that time, there were record lows in sea ice coverage in the
region, Overland said. This year there was more normal coverage in the
Bering area but a record low on the Atlantic side of the Arctic.
In the past when such a shift occurred, there would have been no net loss
of ice overall, just a change in where there was a smaller amount. Now,
however, there is both the shift and an overall net loss of ice, he said.
Indeed, the report said Arctic sea ice coverage this past March was the
lowest in winter since measurements by satellite began in the early 1970s.
Jacqueline A. Richter-Menge of the Cold Regions Research and Engineering
Laboratory in Hanover, N.H., said the sea ice decline is now being
observed in both winter and summer.
The study was designed to assess the overall impact of climate change in
the Arctic and will be updated annually. It was compiled by researchers
from the United States, Canada France, Germany, Poland, Norway, Sweden and
Russia, she said.
In addition, 2007 has been designated the International Year of the
Arctic, with intense scientific study of the region planned.
There have been many changes over the Arctic land areas, too, said
Vladimir E. Romanovsky, a professor at the geophysical institute of the
University of Alaska. These include changes in vegetation, river discharge
into the Arctic Ocean, glaciers and permafrost.
The tundra is becoming greener with the growth of more shrubs, he said.
This development is causing problems in some areas as herds of reindeer
migrate.
At the same time, there is some decrease in the greening of the northern
forest areas, probably due to drought. The glaciers are continuing to
shrink and river discharge into the Arctic Ocean is rising, Romanovsky
said.
There has been a significant warming of the permafrost over the past 30
years, he added.
Much of the damage to the permafrost soil can be blamed on human
construction activities and fires, he said. In many areas, this frozen
ground is close to the melting point and soon could begin to thaw.
Overland said the changes are affecting wildlife in the Arctic. Those in
the middle levels of the ocean, such as pollock, seem to do well; those on
the surface ice or the sea floor, such as walrus or crabs, are not coping
as well.
"We're seeing a lot of indicators of climate change in the Arctic and that
may be an indicator for change in other parts of the world," Overland
said.
Most of the heating from the sun comes to the equator and subequatorial
regions, and a lot of heat leaves by radiation from Arctic, he said.
"The temperature difference between the Arctic and equator drives all of
our weather," Overland said. If the Arctic warms up and that difference is
reduced, weather could change, though people remain unsure about the
effect.