Yamal Encounters Open Lead at the North Pole
A recent article by John Noble Wilford in the New York Times ( August 19, 2000, registration required) and picked up by numerous other periodicals (for example, the BBC World News, August 20, 2000 and the Seattle P/I, August 19, 2000) has claimed that "the North Pole is melting". The article is based on reports by Drs. James McCarthy and Malcolm McKenna who traveled to the Pole onboard the Russian icebreaker Yamal in July. The Yamal encountered favorable ice conditions enroute and upon arrival found an area of open water at the Pole. This inspired comparisons to an ice-free Arctic Ocean such as may have last occurred 50 million years ago, and led to discussion of the implications for global warming. The article prompted numerous inquiries to the Principal Investigators and the website of the North Pole Environmental Observatory (NPEO) project, and one of these resulted in a panel discussion of the issue on the program Weekday of National Public Radio station KUOW 94.9 FM on August 23 . If you have RealPlayer installed, you may listen to that discussion by clicking here. Subsequent news coverage (Dallas Morning News, August 28, 2000 and New York Times, August 29, 2000, registration required) did present a more balanced view of the state of the summer Arctic ice pack. We have added this special section to address questions about open water at the North Pole raised by the original article.
The comparison of open water at the Pole to an ice-free Arctic Ocean is something of an exaggeration. Typically the areal concentration of open water in the ice pack during the summer is 10%. Therefore, under normal conditions a visitor to the North Pole in late summer should expect to find some open water approximately one time out of ten. The National Snow and Ice Data Center posted satellite imagery from July 26, 2000, and although the region near the North Pole was obscured by thick clouds, a fairly typical summer pattern of jumbled ice floes and frequent leads of open water is evident in the central Arctic Ocean. Among the historical anecdotes related to us about open water at the Pole is the surfacing of USS Queenfish(SSN 651) during summer 1970 through a polynya a few hundred yards across about 500 yards from the North Pole.
While the importance of open water at the Pole has been overemphasized, it is consistent with the mild ice conditions encountered by the Yamal during her transit and the relatively thin ice conditions we observed over a wide area during deployment of the Observatory. It also highlights important trends in recent years.
During the deployment of the NPEO we transited between Canadian Forces Station Alert on the north end of Ellesmere Island and the Pole numerous times, searching for an observatory deployment site and hydrographic survey locations. Although it is difficult to quantify ice thickness precisely by airborne visual observation, we were impressed by the absence of thick, old multiyear ice floes with surface features rounded by multiple summer melt cycles. The pack seemed composed exclusively of one to two-year old ice about two-meters thick. We had to content ourselves with installing the Observatory in ice two meters thick and less. The NPEO group was fortunate to be in contact with Mr. Ron Sheardown who flew across the Arctic Ocean last spring and was on board the Yamal. Mr. Sheardown is an experienced ice observer and polar aviator with many landings on sea ice to his credit. He reported that during his spring flight, he observed relatively young ice in the region of the Pole and, interestingly, the oldest ice near Alaska.
This year's observations
of thin ice conditions in the North Pole region may be another manifestation
of well established trends. Rothrock
et al. (1999) have analyzed ice draft measurements from submarines
and found that the average sea ice thickness in the central Arctic
Ocean has decreased by more than 40%, from 3 meters to 2 meters, in the
last 20-30 years. Several investigators have described the reduction
in horizontal ice extent. Most recently Parkinson et al. (1999)
found a decrease in ice extent of 3% in the last 20 years. Observations
in recent decades also show a decline in sea level atmospheric pressure
over the Arctic, a change in the Arctic Ocean circulation, rising surface
air temperature in the Russian Arctic, and increasing permafrost temperatures
in some areas. These changes are motivating the development of the Study
of Environmental Arctic Change (SEARCH) as a research initiative
under the U.S Interagency Arctic Research Policy Committee. The
changes, their relation to changes in the atmospheric circulation of the
Northern Hemisphere, their implications for global climate change, and
the research needed to address the changes are described in the Draft
SEARCH Science Plan. One of the key elements of the research plan
is to establish programs of long-term observation such as the North
Pole Environmental Observatory. The
complete citations are:
C.L.Parkinson, C.L., D.J.Cavalieri, P.Gloersen, H.J.Zwally, and J.C.Comiso. Arctic sea ice extents, areas, and trends, 19781996, J.Geophys. Res.,104(C9), 2083756,1999.
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