During the first half of April 2018, scientists at the U.S. National Snow and Ice Data Center (NSIDC), together with NASA climate researchers, reported that Arctic sea ice had reached its annual maximum extent. Yet, as in the preceding years, the ice-covered area remained well below the average of earlier decades. [source]
The source notes that the four lowest annual maximum extents then observed in the satellite record had all occurred during the previous four years, continuing a roughly decade-long decline in Arctic sea-ice coverage and surrounding waterways.
Both annual maximum and minimum Arctic sea-ice extent had declined over the approximately forty years of satellite observations discussed in the article. The proportion of thick multi-year ice had also fallen substantially. This retreat and thinning created new opportunities for marine navigation while simultaneously raising serious environmental concerns. [source]
The 2018 winter maximum
A map in the original article shows average Arctic ice concentration around March 17, when the ice reached its annual maximum. The source gives the extent as approximately 14.48 million square kilometres. Lighter and white regions represent areas meeting the satellite-based threshold of at least 15 percent ice concentration used to define the ice-covered extent.
The article states that the 2018 maximum was among the lowest in the satellite record and about 1.16 million square kilometres below the 1981–2010 average. An accompanying animation compared late-March Arctic ice coverage through the satellite era beginning around 1979. [source]
Environmental consequences
The declining ice cover concerned scientists because Arctic plants, animals, plankton, and human communities must adapt to warmer summers and winters and increasingly ice-free ocean conditions. The article also discusses changing atmospheric and oceanic circulation and links these changes with shifts in upper-atmospheric jet-stream patterns and unusual weather at high and middle latitudes.
A new shipping environment [source]
At the same time, diminishing ice was changing marine transportation. In August 2017, a specially strengthened commercial vessel travelling from Norway toward South Korea crossed Arctic waters without an accompanying icebreaker. The journey took about 19 days, roughly a week less than the conventional route through the Mediterranean and Suez Canal according to the source. [source]
Another map showed Arctic voyages between September 2009 and January 2017. Over those seven years, the article reports that the centre of shipping activity shifted on average about 300 kilometres closer to the North Pole. Smaller vessels, including fishing boats, were also penetrating farther into polar waters.
Russia, China, Canada, the United States, and Iceland were among the countries expanding maritime capabilities to take advantage of increased access. Routes discussed include Canada's Northwest Passage, the Northern Sea Route, the Northeast Passage, and waters north of Russia and Siberia, all of which can potentially shorten some voyages among Asia, Europe, and North America.
These opportunities come with risks. Scientists and environmental advocates cited in the source raised concerns about pollution, oil spills, and disruption to Arctic marine ecosystems. Older navigation systems and limited emergency infrastructure can also increase danger to crews operating in remote polar waters. [source] [source] [source]
Planning for a changing Arctic
The article closes with the work of Paul Arthur Berkman, director of the Science Diplomacy Center at Tufts University and a senior coordinator/researcher associated with Pan-Arctic Options. The initiative sought to combine natural- and social-science research with planning and geographic information in support of sustainable economic activity in polar regions.
Researchers involved in this work aimed to develop practical policies and infrastructure for activities such as search and rescue, navigation, and pollution response while recognizing countries' economic-development objectives. [source] [source]
Sea-ice measurements and shipping developments above reflect the information available when the original article was published in April 2018. [source]