(by Karl Magnus Eger)

The three potential transport corridors share some of the same natural challenges. However, a set of detailed natural characteristics makes each corridor unique, as well as more or less favourable in terms of shipping operations.

The Northeast Passage

Of all the alternative routes for navigation on the NEP, whether it is the selection is strongly affected by natural conditions. One of the primary factors when selecting a favourable shipping lane on the NSR is the distribution of sea ice. The ice conditions vary greatly between seasons, between years, and between the marginal seas.

A major percentage of the recent NEP commercial shipping activities do not involve the NSR. Under normal conditions, winter navigation on the eastern NSR is not beneficial, and commercial operations are restricted to the summer season. Currently, the only year-round transport on the NSR is the Kara Sea Route. All other transport is carried out only during summer. The summer season has traditionally been defined as June-October, but favourable ice conditions and technological improvements have gradually allowed an extended summer season.

Navigation during the winter season (November-May) is generally much more difficult than in the summer season, due to the thicker ice cover. An important feature of winter navigation is the fast ice – stable, immovable ice which is fastened to the coastline. Fast ice is very difficult to pass through, and normally it is preferable to avoid it by using northerly routes. Nonetheless, if off-shore winds prevail, one will often during winter find open leads at the edge of the fast ice – so called polynyas, which are very suitable for navigation.

While the ports of Barents Sea is almost completely ice free even in the winter, no parts of the NSR are completely ice free even during the most favourable summer month (September). Each end of the NSR – the south-western Kara Sea and the south-western Chukchi Sea – has the lightest ice conditions, with the East Siberian Sea having clearly the most difficult ice conditions. This corresponds with navigational experience, where the East Siberian Sea has been seen as the most difficult sea to navigate, and also being the main bottleneck in terms of navigation. Moreover, the difficult conditions in the East Siberian Sea has to do with the ice massifs, consisting of multiyear ice, and which often extends almost to shore even during summer due to currents and winds.

Variations in water depth and narrow straits are other key factors that decide which navigation course to set on the NSR. Since most of the NSR consists of continental shelves, a major part of the corridor and especially the straits are shallow. Shoals depth less than 20m are by no means rare and increases the risk that deep-draft vessels may run aground. However, there are great variations between the marginal seas of the NEP. Although the western and eastern Barents Sea has depths of 100-300m, the Kara Gate (the main shipping strait between the Barents and Kara seas) is mere 20-30m deep. Furthermore, the Kara Sea has an average depth of 90m, but some areas, however, are as shallow as only a few meters. Of key importance to shipping on the NSR is that four straits require mandatory icebreaker escort, organized by the MOH. This includes: the Vilkitskii Strait, the Dmitri Laptev Strait, the Shokalskiy Strait and the Sannikov Strait. The Vilkitskii Strait is a key NSR Strait between the Kara and Laptev seas. Although it has adequate water depth for deep draft vessels, it is mainly ice covered, except from a short period in the summer season. Thus, Shokalskiy Strait is a second possible route north of Vilkitskii Strait. The Laptev Sea has an average depth of 600m, but as one draws near to the New Siberian Islands the sea becomes shallower than 20m. The route alternatives between the Laptev and the East-Siberian are either through the Dmitri Laptev Strait or the Sannikov Strait. Both straits have minimum depths of 12-13m, a limiting factor in terms of maximum ship draught on the NSR. Long Strait links the East Siberian and the Chukchi seas. In this part of the NSR, draught should not be a problem for any ship that keeps well offshore from the mainland.

The Northwest Passage

The NWP is difficult to navigate due to the pattern of ice drift from the central Arctic Ocean. As Arctic warming continues, it is likely that much of first year ice in the Canadian Archipelago will break up much earlier than what is currently the case. This will allow old hazardous ice from the permanent ice pack to enter the NWP in greater quantities.

There are potentially seven routes through the NWP, of which three are considered as being practical for regular navigation: This includes: 1) the M’Clure Strait, 2) the Prince of Wales Strait and 3) the Peel Sound (see Figure 4.6). The presence of sea ice and depth restrictions constitutes the critical factor in terms of NWP navigation. Ice conditions on the NWP are very complex. Observations of minimum sea-ice extent from year to year in the eastern and western regions of the NWP vary significantly. Thus, inter annual variability is not conducive in order to plan a reliable marine transportation system.

Navigation through the M’Clure Strait is the shortest and deepest NWP route alternative with an average depth of 400m. However, it is also the most difficult passage due to the severe ice conditions. Old, hard and dangerous ice is present most of the time which can seriously delay the vessels progress and potentially damage even ice strengthened ships. In addition, even during the most favourable shipping seasons (10-15 days), there will be a risk of encountering multiyear ice. The route that passes through the Prince of Wales Strait is an easier alternate deep-draft route which avoids severe ice in the M’Clure Strait. However, a limiting factor is the depth variations which are less than 20m in some parts of the strait. Normally this strait is open during September however the presence of multiyear ice is still seen as a threat to ships. Moreover, as the melting continues, it is likely to be an increase in the presence of old ice as the decrease in land-fast ice in the western part of the Archipelago would allow more old ice from the Arctic Ocean to pass into channels between the islands. The route that passes through the Peel Sound is the longest NWP transit and the most frequently used.  However, navigation of this route is restricted to ships having a maximum 10m draught. Currently this route is passable from mid-August to mid-September. However, the presence of multiyear ice in this sound is seen as a significant challenge and is likely continue to be so.

The Trans Polar Passage

When considering the natural characteristics and shipping on the TPP, the central Arctic Ocean has no draft limitations, narrow straits or complex archipelago which puts constraints on navigation. Nonetheless, the sea ice conditions are the key factor of limitation in terms of any potential commercial shipping routes. No commercial cargo ship has yet crossed the central Arctic Ocean. There are huge uncertainties as well as variations between different climate models trying to predict the development of ice conditions. In terms of any regular shipping on these routes, however, DNVs Arctic Container Project (ARCON)  simulations indicates that the ice will be too heavy and the calculated costs too high for any regular transport. Models indicate that the ice conditions will continue to be heavy during winter and spring seasons, even in 2050, and the route is not expected to be completely ice free in summer. Currently the TPP is not an alternative.

The Passages in Comparison

As demonstrated, both the NEP and the NWP faces large water depth variations and complex archipelagos which put constraints on the technical construction and capacity of the vessels operating on these corridors. Moreover, the sea ice conditions vary significantly both between and within each of the three passages presenting different challenges to navigation on the NEP, the NWP and the TPP.

The availability of icebreakers is an important feature. Russia has a considerable larger and stronger icebreaker fleet to support operations on the NSR than Canada has for the NWP. Russia has 5 nuclear icebreakers available for NSR support, in addition, several river and diesel icebreakers operating on a year-round basis. Canada operates 5 diesel-powered icebreakers only for seasonal (May-November) NWP operations.

From a navigational point of view, the NWP will be the last area where the multi-year ice will disappear and shipping through this Passage will remain risky even in the summer season. It is not very likely that the TPP is going to be a used as a regular transport corridor. The ice models indicate that the ice conditions will be too heavy for any commercial shipping. Currently, the NEP/NSR seems to offer the best operating conditions.

Karl Magnus Eger, 2010, Comparison of Operational Conditions along the Arctic Routes, CHNL.©