Arctic sea-ice retreat

The National Snow & Ice Data Center at the University of Colorado Boulder reported last month that the Arctic sea-ice reached its lowest extent for 2018 on 23 September. Measuring 4.59 million square kilometres, the sea-ice was at its six lowest extent in the satellite record (tied with 2008 and 2010), well within the boundaries of what scientists have described as the ‘new normal’ for the Arctic (see PolarNotes #17) and 1.63 million square kilometres below the 1981-2010 average of yearly minimum extents. Last year, the sea-ice minimum was 4.64 million square kilometres. The sea-ice in the Central Arctic has been unusually slow to reform this October, likely because of warmer than average air and ocean temperatures.  

The announcement came as scientists continue to reflect on the worrying discovery that in 2018, for the first time on record, an area of the Arctic known as the ‘Last Ice Area’ was observed breaking up. The Last Ice Area describes a vast area of the icepack north of Greenland where the oldest and thickest Arctic sea-ice tends to gather. In January, Arctic sea-ice was at a record law. Then, in February scientists spotted a polynya-like hole (essentially a stretch of open water surrounded by ice) in the Last Ice Area. In August, unusually warm temperatures combined with prevailing winds to again push the ice further away from the north coast of Greenland, opening up the Last Ice Area for a second time.  

Meanwhile, the summer saw a number of significant shipping events. Perhaps the most notable involved the Venta Maersk, which became the first container vessel to navigate the Northern Sea Route. Until last year, Maersk had repeatedly stated that the company was not interested in Arctic shipping routes. The Venta Maersk sailed from Busan, South Korea at the end of August with a cargo of frozen fish, chilled produce and electronics to St Petersburg, Russia. Maersk tried to downplay the achievement noting that the purpose of the “one-off trial” was to gain operational experience and to test vessel systems. Interestingly, the ship used a high-grade, ultra-low sulphur fuel instead of heavy fuel oil. This month, the International Maritime Organisation met to discuss a ban on the use of heavy fuel oil in the Arctic.  

In the Canadian Arctic, potential ship operators were given a stark reminder of the dangers of operating in Arctic waters when the Russian research-cruise ship, Akademik Ioffe ran aground in the Gulf of Boothia. The 102 passengers and 24 crew members, fortunately none injured, had to wait nearly nine hours for a Hercules aircraft to arrive from the Canadian National Defence Joint Rescue Centre, 12 hours for a second plane to arrive, and 20 hours for a Canadian Coast Guard Helicopter to fly over. It took the same amount of time for Ioffe’s sister ship Akademik Vavilov to provide aid after being diverted by the tour operator. Had the ice conditions and weather been less favourable, the stricken vessel could have faced a potentially more dangerous scenario. Following the rescue, the Vavilov was itself overloaded with passengers and had to be escorted by Canadian Coast Guard vessels.  

Future maritime activity in the Arctic remains highly dependent on the ability of scientists to measure, track and understand what is happening to the sea-ice. An important new instrument for this is NASA’s Ice, Cloud and land Elevation Satellite-2 (ICESat-2) which was launched into polar orbit in September. ICESat-2 will be used to estimate the annual height change of the Greenland and Antarctic ice sheets to within four millimetres. It will also be able to measure the thickness and overall volume of Arctic sea-ice. The new satellite will provide unprecedented resolution and coverage of Arctic ice completing other data sets such as that provided by the Cryosat-2 programme run out of University College London.