Table 1.

Observations of changes in permafrost and related hydrologic and ecosystem variables in pan-Arctic regions. Selected studies are limited to those published since 2000. ALT, active layer thickness; PF, permafrost; SW, surface water; GW, groundwater. Numbers in parentheses in the middle columns refer to the numbered studies in the last column for each attribute. “Data gap” in last column denotes a lack of observational data to determine change in the attribute.

Observed attributeTrajectoryGeographic locationTime frameSelected references
Permafrost distribution
ALTincrease (1,2,6); variable (3,4); high inter-annual variability (5)Subartic Sweden (1); Arctic Russia (2); Alaska, USA (3); Pan-Arctic (4); N Europe (5), E Siberia (6)varies(1) Åkerman and Johansson, 2008; (2) Mazhitova et al., 2008; (3) Osterkamp, 2005; (4) Hinzman et al., 2013; (5) Harris et al., 2009; (6) Brutsaert and Hiyama, 2012
Spatial extent8% (1); decrease by 38% (2)Tanana Flats, Alaska, USA(1); NW Territories, Canada (2)1949–1995 (1); 1947– 2008 (2)(1) Jorgenson et al., 2001;(2) Quinton et al., 2011
Open vertical taliksinferred increase in abundanceSiberia1973–2004Smith et al. 2005; data gap
Lateral taliksinferred increase in abundanceYukon Flats, Interior Alaska1979–2009Jepsen et al., 2013; data gap
Water flux
Supra-PF flowincrease (1); variable (2)Yukon River Basin, USA/Canada (1); N Sweden (2)1950–2004 (1); 1910–2010 (2)(1) Lyon and Destouni, 2009; (2) Sjöberg et al., 2013
Lake/GW exchangeepisodic localized increase (1); increased lake size due partly to PF thaw (2)Seward Pennisula, Alaska, USA (1); E Siberia (2)1950–2002 (1); 1992–2008 (2)(1) Yoshikawa and Hinzman, 2003; (2) Fedorov et al., 2014
Soil drainageexpected increasedata gap; expectations derived from modeling studies
Sub-PF flowexpected increasediscontinuous PF regionsdata gap; limitations on measurement capability; indirect evidence from baseflow increases (see below)
BaseflowincreaseYukon River Basin, USA/Canada (1); N Eurasia (2); NW Territories, Canada (3); pan-Arctic region (4)past 3–7 decades(1) Walvoord and Striegl, 2007; (2) Smith et al., 2007; (3) St. Jacques and Sauchyn, 2009; (4) Rennermalm et al., 2010
Water distribution
Soil moisturevariable; depends on landscape position and other factors (1,2); increase (3)Interior Alaska, USA (1,2); Abisko region Sweden (3)(1) Jorgenson et al., 2001; (2) O’Donnell et al., 2012b; (3) Christensen et al., 2004
Lake and wetland distributiondecrease (1); slight decrease in net area (2, 3)Siberia (1); Old Crow Basin, Canada (2); Yukon Flats, Alaska, USA (3)1973–2004 (1); 1951–2001 (2); 1979–2009 (3)(1) Smith et al., 2005; (2) Labrecque et al. (2009) and references therein; (3) Rover et al., 2012
GW storagevariable (1); increase (2)Arctic (1); Lena River Basin, Eurasia (2)2002–2008 (1);
2002–2010 (2)
(1) Muskett and Romanovsky, 2011;
(2) Velicogna et al., 2012
Aufeisno change in spatial distribution; volume change unknownBrooks Range, Alaska, USApast 100+ yrYoshikawa et al., 2007
River ice thicknessdecrease, with variability in max. thickness reductionnorthern latitude synthesisrecords spanning 1912 to 2006Beltaos and Prowse, 2008 (a review)
Ecosystem variables
Shifts in vegetation structure and compositionoverall increase in shifts: forest and plateau loss (1); birch forest shift to fens and bogs (2); shrub to graminoid dominance (3)NW Territories, Canada (1); Alaska, USA(2); Abisko region, Sweden (3)1947–2008 (1); 1949–1995 (2); 1970–2000 (3)(1) Chasmer et al., 2010; Baltzer et al., 2014; (2) Jorgenson et al., 2001; (3) Christensen et al., 2004
SW hydrologic connectivityincrease at local scaleScotty Creek, NW Territories, Canada1996–2012Connon et al., 2014
Subsurface hydrologic connectivityexpected increasedata gap
Seasonality of streamflowdecrease in max/min discharge ratio (1, 2); earlier spring melt (2)Siberia (1); NW Territories, Canada (2)1942–1998 (1); 1973–2011 (2)(1) Ye et al., 2009; (2) Yang et al., 2015
Seasonality of stream temperaturedecrease: warming (cooling) trends in early (late) open-water seasonSiberia1950–1992Liu et al., 2005
  • Includes suprapermafrost and intrapermafrost taliks.

  • Using streamflow recession intercept as a proxy for assessing suprapermafrost flow.