Over the last 50 years, the Arctic has been warming four times faster than any other place on Earth, causing rapid melting of sea ice. For shipping and trade, this lack of Arctic sea ice could mean a much shorter trade route between the Atlantic and Pacific oceans. Without it ships must go out of their way through the considerably longer Panama Canal.
But a warmer Arctic doesn’t actually mean it will be smooth sailing for shipping according to a new study. While climate change is causing seasonal sea ice to melt, it’s also coaxing older and thicker ice to break-off from a region north of Greenland, researchers have found. This thick ice drifting into the sea creates several “choke points” along the shipping channels, preventing smooth transit, they write.
“It’s true that the Arctic sea ice in general is showing significant retreat and melting, and will continue to do so, but our new study shows that it’s not a simple story,” Alison Cook, lead author of the study, and researcher at the Scottish Association for Marine Science in Scotland, told the Canadian Broadcasting Corporation (CBC).
For hundreds of years, explorers and sailors have tried to find safe routes through the notoriously dangerous Northwest passage, connecting the Atlantic and Pacific oceans via the Arctic. Many died trying. Climate change and the melting sea it caused has been a game changer. The number of ships that successfully crossed in the Canadian Arctic has quadrupled between 1990 and 2019.
Moreover, in the summer of 2007, the northwest passage saw record-low sea ice. But does continued warming mean increased ship navigability? To find out, the researchers analysed 15-years of ice charts from 2007 to 2021, maintained by the Canadian Ice Service.
The analysis showed that warming did not equate to prolonged shipping seasons. Even though the number of ships going through the passage may have increased, the number of weeks the vessels could transit without trouble declined considerably. For example, the annual shipping season in the Eastern Beaufort Sea declined from around 23 weeks in early years (2007-2011) to about 13 weeks in recent years (2017-2021). In the M’Clure Strait, the shipping season reduced from 6.5 weeks early on to only around 2 weeks more recently.
The researchers attribute the reduction in shipping season to the several meters thick, multiyear ice—ice that has survived a few summer melts—breaking off from a region called the Last Ice Area, a polar region north of Greenland and Canada.
“This ice is even more hazardous and is creating ‘choke points’ along certain sections of routes, leading to reduced shipping season length,” Cook said in a statement.
The study makes “a plausible case that multiyear sea ice poses an increasing risk to Arctic shipping”, Dustin Isleifson, Director of the University of Manitoba’s Centre for Earth Observation Science in Canada, told the Globe and Mail. Iseifson was not involved with the study.
Banner image of ship moving through Arctic sea ice from Pixabay (public domain)
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