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Climate change might open up Northwest Passage to shipping by the middle of the century.

The views expressed are those of the author and are not necessarily those of Scientific American.

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Differences in transit routes for two kinds of vessels (red and blue) enabled by shrinking Arctic ice levels and opening of the Northwest Passage by 2050 (Image: Smith and Stephenson, PNAS, Early Edition)

Investigating what is sometimes seen as one of the more favorable effects of climate change, a pair of scientists from UCLA has done a careful analysis of the melting of Arctic sea ice and concluded that it could lead to ships traversing the ice-free Northwest Passage (NWP) by 2050. It would also lead to much shorter transit times through the existing North Sea Passage (NSR). These developments may greatly reduce the time and cost of shipping but would also lead to unforeseen economic and geopolitical complications.

The study looked at estimates of sea ice melting – gathered from both models and observations including satellite measurements – and then used seven different climate models to calculate the decrease in sea ice and its impact on shipping over the next few decades. The models are General Circulation Models (GCMs) that have been routinely used by the IPCC to estimate diverse impacts of climate change, including changing ice and sea levels. From the IPCC predictions the authors used two different climate forcings – measures of global temperature changes induced by human and natural activities – to calculate the distribution, thickness and changes in sea ice in the Northwest and North Sea passages. The goal of the study was to broadly estimate how the opening up of the Northwest Passage would affect the transit of two major classes of shipping vessels in the peak month of September, when sea ice levels are at their lowest. The relevant ships are the so-called PC6 and open water (OW) vessels which are designed to navigate ares with low to moderate ice density. The report asks only for the optimal route for these vessels in terms of transit time since other factors like economics and legal issues are difficult to take into account.

The researchers started by testing their models by hind-casting the distribution of ice for the period 1979 – 2005. Once the models were reliably benchmarked for this data set, they were then asked to predict the accessibility of the NWP and the NSR during the next few decades. The results pointed to a significant opening up of transit routes to both PC6 and OW vessels.

For the NSR, sea-ice restricted the probability of shipping during the 1979-2005 period to just 40%. This probability rises to more than 95% for the period 2040-2060. The effects on the NWP are even more striking. The opening up of unprecedented shipping routes by 2040 or so is plainly evident in the models. Figures C and D illustrated above display the significant differences for transit times for PC6 (red) and open water (blue) vessels over the next half-century. The line weights indicate number of successful transits. As the authors put it:

“The emergence of a robust PC6 corridor directly over the North Pole indicates that, in either scenario, sea ice will become sufficiently thin (e.g., <1.2-m thick at 100% ice concentration) and/or diffuse such that a critical technical threshold is surpassed, and the shortest great circle route thus becomes feasible, for ships with moderate ice-breaking capability…the Northwest Passage (NWP), arguably the most historically famed of potential shipping routes through the Arctic, has the lowest navigation potential both historically and at present but opens substantially by 20402059.”

The models find that for voyages from Eastern North America, the NWP might be the favored route for shipping by mid-century, essentially allowing transport 100% of the time during the peak season. The report concludes that

“Put simply, by midcentury, September sea ice conditions have changed sufficiently in the NWP such that trans-Arctic shipping to/from North America can commonly capitalize on the 30% geographic distance savings that this route offers over the NSR.”

These significant savings would undoubtedly provide a great incentive for several countries to take advantage of the newly opened shipping corridor. The authors conclude by reasonably speculating that international trade and economic agreements will have to be significantly revised to take this new situation into account. In addition the opening up of what has historically been a most attractive shipping route would lead to the unforeseen geopolitical consequences which inevitably arise from such large-scale planetary changes.

Ashutosh Jogalekar About the Author: Ashutosh (Ash) Jogalekar is a chemist interested in the history and philosophy of science. He considers science to be a seamless and all-encompassing part of the human experience. Follow on Twitter @curiouswavefn.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Shoshin 4:41 pm 03/6/2013

    Obviously the editors didn’t like my previous comments on the vacuous lack of science exhibited by this article and the comments were censored.

    Here we go again…..

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  2. 2. dubay.denis 5:13 pm 03/6/2013

    I’m sure the two study authors at UCLA and the editor at Ohio State would appreciate your review. Their email address is available at the Proceedings of the National Academy of Sciences web site link above, go ahead and forward your comments directly to them.

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  3. 3. jdinnen 5:19 pm 03/6/2013

    What an interesting story. I recently saw the film CHASING ICE at a film fest, and it shows the calving of the glaciers so vividly – incredible. A ton of photos are on the website –

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  4. 4. Shoshin 6:38 pm 03/6/2013

    Everyone who has actually been up there and seen the extreme harshness of the environment first hand please stand up.

    Sound of my chair. sound of my knees as I stand up. Note lack of sound from dubay.denis

    This entire article is based on increasingly shaky IPCC projections. A speculative article at best, misleading and ballyhoo at worst.

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  5. 5. mcsqrd 9:50 pm 03/6/2013

    “Everyone who has actually been up there and seen the extreme harshness of the environment first hand please stand up.”

    I’ve been up to Barrow, Alaska quite a few times over the past ten years, and the decrease in the arctic sea ice due to AGW is obvious to the folks up there. The Coast Guard here in Alaska is also starting to get concerned about this issue because most of their presence is centered around Kodiak, far to the south, and as the sea traffic up north increases they will be needed up there more often.

    And the climate in Barrow is actually less harsh than in the central part of the state. Barrow has dark winters but not as cold as other parts of Alaska.

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  6. 6. thevillagegeek 12:10 am 03/7/2013

    Shoshin, the Navy seems to be taking these things rather seriously, and I think that it has had quite a few people up there that have seen the harsh environment first hand. I’d lend that a lot more weight than the typical doubtcasting from one of the usual suspects.

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  7. 7. dieselpop1 3:39 pm 03/7/2013

    I suppose it would be inconvenient to mention that there have been numbers of ships that have sailed across the Arctic going back to more than a hundred years ago and that metal fittings from Viking ships have been found off the cast of Ellesmere Island.

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