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Shell unlucky with Chukchi ice; exceptionally low cover elsewhere
With the Arctic sea ice cover steadily retreating in recent years, Shell really seems to be out of luck in having to delay the start of its planned Chukchi Sea drilling because of an exceptionally heavy ice cover in the area when it wants to site its drilling rig.
Mark Serreze from the National Snow and Ice Data Center, or NSIDC, told Petroleum News July 16 that the ice conditions that are impacting Shell’s drilling plans represent a regional variation within a continuing trend of sea ice loss for the Arctic as a whole. Essentially, weather conditions, particularly the wind, have pushed exceptional amounts of ice into the Chukchi and western Beaufort seas, while in the eastern Beaufort, for example, there is relatively open water.
“If you take the total Arctic sea ice extent for Arctic as a whole, it’s very low and at or near a record low for the date,” Serreze said. “This is just a matter of the regional patterns of variability and what you are seeing there is just what the effects of the weather patterns have been this year.”
Record lows According to NSIDC, June saw an especially rapid melt of sea ice across the Arctic, with record low sea-ice extents occurring for brief periods in the middle of the month.
“Strong ice loss in the Kara, Bering and Beaufort seas, and Hudson and Baffin bays, led the overall retreat,” NSIDC wrote in its report for June.
A field worker from the Cold Regions Research Laboratory making measurements in landfast ice in the Beaufort Sea offshore Barrow reported ice that was thicker than had been observed in previous years but that was melting relatively rapidly, NSIDC said.
At 4.24 million square miles the Arctic sea ice extent in June was 456,000 square miles below the 1979 to 2000 average. By the end of June the ice extent had dropped to a level that would normally be expected on July 21, thus putting the ice melt about three weeks ahead of its long-term average schedule, the NSIDC report says.
This year’s June ice extent was the second lowest since satellite ice observations began in 1979, with 2010 having the lowest June extent. The Arctic sea ice extent decline since 1979 is trending at 3.7 percent per decade.
—Alan Bailey
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