Abstract
Icebergs present a known hazard to ships operating in ice-infested waters. As iceberg production rates vary, potentially compounded by climate change, it is becoming increasingly important to understand the extent to which icebergs pose navigational hazards. In this study, we explore the relationship between historic ship tracks derived from Automatic Identification System and iceberg drift locations obtained from in situ satellite trackers and the Canadian Ice Island Drift, Deterioration, and Detection Database. Using an iceberg–ship coexistence index we quantify this relationship throughout the eastern Canadian Arctic (ECA) from 2012 to 2019. Comparing 2012–2015 to 2016–2019, the total number of unique vessels operating in the ECA more than doubled. At the same time, icebergs were consistently observed throughout the entire ECA, specifically in Nares Strait, eastern Lancaster Sound, and east of Baffin Island. Regions where the largest increases in both icebergs and ships occurred were along the east coast of Baffin Island and east of Bylot Island, most often involving dry bulk vessels, and in Smith Sound between Ellesmere Island and NW Greenland involving passenger vessels. Recent reductions in the mean ice strengthening of ships operating in the ECA means the seriousness of any potential iceberg collision is likely increasing towards present day.
1. Introduction
Ship traffic throughout the Canadian Arctic Archipelago (CAA) has more than tripled in recent decades, with the average number of voyages increasing from 104 year−1 from 1990 to 1994 to 381 year−1 from 2015 to 2019 (Dawson et al. 2022). Many communities in the North are inaccessible by road and therefore heavily reliant on shipping, meaning that the primary purpose of much of the shipping is related to resupply, although many voyages are dedicated to mineral resource extraction (Stephenson and Smith 2015; Dawson et al. 2018). The greatest increase in ship traffic has been observed in Hudson Strait, where many mines are located on adjacent lands, followed by the Beaufort Sea and Baffin Bay. While shipping season length varies spatiotemporally throughout the CAA (Haas and Howell 2015; Copland et al. 2021; Mudryk et al. 2021), the entrance of the Northwest Passage (NWP) in eastern Lancaster Sound has shown some of the most significant increases in season length since 2007 (Cook et al. 2024). Since 1990, the fastest-growing shipping sector, by kilometres travelled, has been pleasure crafts, such as recreational sailboats and private yachts (Dawson et al. 2018).
Icebergs that calve from tidewater glaciers in the CAA and western Greenland frequently drift into these same areas where ships are operating, including throughout Baffin Bay, where the icebergs typically transit in a counter-clockwise direction before drifting southwards along the east coast of Canada (Valeur et al. 1996). There is a great deal of inter-annual variability in terms of the number of icebergs that reach the regions termed “Iceberg Alley,” i.e., the area between Baffin Bay and the Grand Banks of Newfoundland, which is a region that has several offshore oil platforms and a large numbers of vessel movements (Sudom et al. 2014). Icebergs within Iceberg Alley have been monitored since 1913, one year after the sinking of the RMS Titanic following an iceberg collision on 14 April 1912. The International Ice Patrol (IIP) works in conjunction with the Canadian Ice Service (CIS) to monitor iceberg presence in the North Atlantic Ocean and provide iceberg warnings and charts to those navigating off the coast of Newfoundland and Labrador. However, north of 60°N in the eastern Canadian Arctic (ECA), ice charts lack detailed iceberg information and only indicate that icebergs are present with the broad designation of “bergy waters” (Fig. 1; CIS 2005).
Fig. 1.
Fig. 1. Map of study area, including location of main ocean currents and historical ship-iceberg collisions from 1800 to 2023 (Hill 2010) throughout eastern Canada. Additional details on collisions are included in Table 1. Black dotted line shows the iceberg chart limit of 60°N, above which iceberg charts are not regularly issued. Dotted green line represents Canadian Coast Guard NORDREG Zone (Justice Laws 2010). Glacier outlines: Randolph Glacier Inventory (RGI) 6.0 (RGI Consortium 2017). Projection: NAD83 / Statistics Canada Lambert.
The Arctic Ice Regime Shipping System and Polar Operational Limitation Assessment Risk Indexing System (POLARIS) are used to manage operational limitations for ships in Arctic Canada based on current sea ice conditions and level of vessel ice strengthening. Presently, the ice numeral used in POLARIS to assess risk only considers sea ice type and concentration, but not icebergs. The lack of inclusion of icebergs in current navigational risk assessments in combination with the remoteness of the Canadian Arctic, limited search and rescue (SAR) capabilities (Ford and Clark 2019), and lack of bathymetric data (Chénier et al. 2017), highlights the need for improved long-term monitoring of icebergs and improved assessment of their potential risk to navigation (AC 2009; Arctic Monitoring and Assessment Programme (AMAP) 2017; Kujala et al. 2019; Dawson et al. 2022).
