At a glance – Human activity is driving retreat of arctic sea ice

Posted on 5 March 2024 by John Mason, BaerbelW

On February 14, 2023 we announced our Rebuttal Update Project. This included an ask for feedback about the added “At a glance” section in the updated basic rebuttal versions. This weekly blog post series highlights this new section of one of the updated basic rebuttal versions and serves as a “bump” for our ask. This week features “Human activity is driving retreat of Arctic sea ice“. More will follow in the upcoming weeks. Please follow the Further Reading link at the bottom to read the full rebuttal and to join the discussion in the comment thread there.

At a glance

The Northwest Passage is the sea route around the waters off northern Canada and Alaska. Its discovery and eventual navigation involves a fascinating tale of endeavour, adventure and tragedy, too, for some expeditions ended in disaster.

Of the many mishaps, by far the worst was that which befell Sir John Franklin and the 128-strong crews of his two ships: they were last heard of in 1845. It took many expeditions and almost ten years before their fate was finally pieced together. One thing became clear by then: the Northwest Passage does not take prisoners. Yet at the same time, those searches for Franklin and his crew generated lots of new chart cover of the waters between the islands making up the Canadian Archipelago.

Complete navigation of the Northwest Passage was finally accomplished by Norwegian explorer Roald Amundsen between 1903 and 1906. Amundsen’s boat was relatively small at 47 tons and 70 feet long but usefully it had a very shallow draft. That meant it was able to pass through areas where a bigger boat would have fouled the bottom, thus offering a wider choice of courses to take. Amundsen’s route was criticised in some circles because of that factor – what was the point of making the crossing if bigger freight ships could not? But Amundsen was motivated not by money but by science.

With his experienced crew of six, they spent two winters off the eastern side of King William Island, about halfway through the archipelago, collecting data on Earth’s magnetic pole and local meteorology, traded with the Inuit and developed hunting and fishing skills. Leaving there in August 1905, they reached Nome, Alaska twelve months later. The ice had pinned them in for a third winter. There was not to be a single-season crossing for another 38 years, when Sergeant Henry Larsen of the Royal Canadian Mounted Police managed it in a schooner.

So yes, while the Northwest Passage was successfully navigated before 2007, the current state of the sea ice means that the picture is now quite different. Part of the reason for that is down to the age of much of the Arctic sea ice today. Sea ice that has yet to experience a summer melting season is known as first-year ice. It’s relatively thin, fragile and more vulnerable to melting compared to the ice that has withstood one or more melting-seasons, known as multiyear ice. Multiyear ice can even give a good ice-breaker a run for its money. But now there’s a lot less of it.

During many recent summers the Northwest Passage has become open: freight ships and even cruise liners have steamed through. That doesn’t mean it’s risk-free of course – there are still icebergs to watch out for. Nevertheless, it’s getting to the point where there are various concerns being voiced about the number of ships passing through the area, on both ecological and political grounds. For the Northwest Passage, global warming really is a mixed blessing.

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