Divergent Long-Term Trajectories of Human Access to the Arctic (2011)

Understanding climate change impacts on transportation systems is particularly critical in northern latitudes, where subzero temperatures restrict shipping, but enable passage of ground vehicles over frozen soil and water surfaces. Although the major transport challenges related to climate warming are understood, so far there have been no quantitative projections of Arctic transport system change. Here we present a new modelling framework to quantify changing access to oceans and landscapes northward of 40 N by mid-century. The analysis integrates climate and sea-ice model scenarios with topography, hydrography, land cover, transportation infrastructure and human settlements. Declining sea-ice concentration and thickness suggest faster travel and improved access to existing (+5 to +28%) and theoretical (+11 to +37%) offshore exclusive economic zones of Canada, Greenland, Russia and the US. The Northern Sea Route, Arctic Bridge and North Pole routes are projected to become fully accessible from July–September, averaging ~11, 15 and 16 days to traverse, respectively, whereas the Northwest Passage will not. All eight Arctic states are projected to suffer steep declines (-11 to -82%) in accessibility inland, driven by lost potential for winter road construction caused by milder winters and deeper snow accumulation. Projected ~2-4o C increases in global mean temperature by the end of the century will be strongly amplified in the Arctic (2-9o C), especially in winter (~4-11 o C). Early signals of this are already apparent from observations of decreased summer sea-ice extent together with increased glacier and ice-sheet mass losses, coastal erosion, and duration of seasonal soil thaw. Of these, reduced sea ice and thawing ground have the greatest potential to affect human access to the region, owing to their strong influence on two critical transportation systems: (1) maritime shipping, and (2) temporary winter roads and ice pavements constructed across frozen landscapes. As sea ice is the single greatest obstruction to ship navigation, reductions in its concentration and thickness encourage maritime activities owing to increased navigable area, vessel safety and shipping season length. In the Arctic Ocean, reduced multi-year ice (MYI) is also important because it is harder and thicker than first-year ice. Trans-Arctic routes have the potential for significant distance savings: 40% via the Northern Sea Route (Rotterdam-Yokohama, compared with the Suez Canal); 33% via the Northwest Passage (St Johns-Yokohama, compared with the Panama Canal). Thus, four consecutive record lows in the September sea-ice minimum from 2007-2010 have spurred renewed interest in the Northwest Passage and Northern Sea Route, with the latter successfully traversed by two escorted voyages in 2010 and ten more pending for 2011.