Reprint of an artucle by Peter C. Doherty, University of Melbourne, on The Conversation 18 September 2012.
A combination of 33-year satellite records, measurements made over the past century, and long-term proxy analysis suggests Arctic sea ice may be at its lowest level for more than 1,000 years.
According to the US National Snow and Ice Data Center (NSIDC) figures for August 26 2012, Arctic sea ice cover dropped to less than 4 million square kilometres, tracking below the previous minimum in 2007 and 45% down on the levels recorded in the 1980s and 1990s.
The rate of decline has averaged out at 10.4% per decade.
This massive increase in the amount of ice-free ocean allowed three courageous adventurers to take the flimsy 9.3m fiberglass sloop Belzebub II on a three-month west/east transit of the fabled Northwest Passage, which they completed a short time ago.
Sailing via the M’Clure Strait (first traversed by icebreakers in the 1990s) to the Beaufort Sea, their voyage was not without risk. But they endured nothing like the hardships experienced by Roald Amundsen and his crew of six when they made the very first the east/west NW Passage crossing in 1903-6.
The Gjøa, Amundsen’s 21m, shallow-draft wooden herring boat, was frozen in for two years causing fears that, like the ice-fortified bomb-ships Erebus and Terror and the 129 men of the 1850s Franklin Expedition, they had all been lost.
With iron reinforcement fore and aft, a retractable rudder, and clad in Douglas fir covered by Australian ironwood, the 32m Royal Canadian Mounted Police Schooner St Roch (St Rock) reversed Amundsen’s route to complete a difficult 28-month west/east passage in 1942.
The crew used explosives to break up ice floes and, protected by the rounded hull that allowed the ship to be forced up by encroaching ice, they were frozen in for ten months. That technology was used earlier in Fridtjof Nansen’s Fram, the ship that took Roald Amundsen to Antarctica for his successful 1912 conquest of the South Pole.
Many will have seen Australian Frank Hurleys’ dramatic movie and still photographs of Ernest Shackleton’s 1915 Anatarctic expedition ship, the Endurance, being crushed to matchwood in an ice-vice. Though immensely strong, the Endurance was designed to force through floe ice and had a conventional, deep hull.
After the installation of a much more powerful engine, the St Roch made a much faster east/west transit using a more northerly route, though again with great difficulty due to encountering very heavy ice conditions.
Still, she was the first ship to traverse the Northwest Passage both ways, and the first to make the crossing in one season. The St Roch can be seen at the Vancouver Maritime Museum while, after being displayed for many years in San Francisco (where she was left by Amundsen) and then in Norway, a new home is being built for the Gjøa at the Fram Museum in Oslo. The watery graves of her Victorian majesty’s ships Erebus and Terror are yet to be located.
Though they were not icebreakers in the modern sense, these tough, wooden polar vessels endured conditions that would have crushed the deep-keeled Belzebub II like an eggshell.
Much of Amundsen’s transit was only possible because of the Gjøa’s shallow draft while, even in wartime, there was no suggestion that the St Roch had discovered a route that could be used by naval or supply ships.
With decreasing Arctic sea ice, many ships and smaller boats have made the transit over the past two decades. Now, it seems that the Northwest Passage will soon be officially open for summer business.
Maybe we should consider 2012 as a banner year for the Arctic, just as 1912 marked both triumph (Amundsen) and tragedy (Scott) in the annals of Antarctic exploration.
If though, we accept the majority scientific view that what is happening now with Arctic sea ice may be a bellwether of anthropogenic warming, will we ultimately see 2012 as triumphant, or as just one step in an emerging global tragedy?
Peter Doherty is a professor at the University of Melbourne and is a member of the Board of The Conversation. He also serves in a voluntary, unremunerated capacity as Chair of the Board that provides strategic oversight to the ARC Centre of Excellence for Climate Systems Science.
This article was originally published at The Conversation.
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