Permafrost evolution, degradation, and properties influence terrestrial and aquatic ecosystems in Arctic and boreal regions (Bowden et al. 2012; Hinzman et al. 2005; Shur and Jorgenson 2007), impact infrastructure and economies (Walker and Peirce 2015; Larsen et al. 2008), affect human health (Arctic Climate Impact Assessment 2004), and alter global climate via the permafrost carbon feedback (Koven et al. 2015; Schuur et al. 2015). These effects are germane to all of the policy drivers in this Plan: Well- being, Stewardship, Security, and Arctic-Global System. Understanding permafrost processes and their dynamic linkages with natural and social systems is important for advancing U.S. policy interests for the 2017-2021 planning period and beyond.
Improved understanding of permafrost dynamics requires an interdisciplinary approach linking biotic, abiotic, and social disciplines in order to consider relevant impacts at local to global scales. Permafrost is a fundamental component of the cryosphere in the northern hemisphere, affecting about 24 percent of the terrestrial landscape (Brown et al 1998). Permafrost is defined as ground that remains at or below 0°C for at least two consecutive years (Van Everdingen 1998). Four zones describe the lateral extent of permafrost regions: continuous (90-100 percent), discontinuous (50-90 percent), sporadic discontinuous (10-50 percent), and isolated discontinuous (< 10 percent). Permafrost zones extend across 80 percent of Alaska. Continuous and discontinuous permafrost underlie 32 percent and 31 percent of the state, respectively, while sporadic permafrost underlies about 8 percent of the state, and isolated discontinuous perfmafrost, an additional 10 percent (Jorgenson et al. 2008). Interactions between climate, topography, hydrology, and ecology operating over long time scales regulate permafrost presence and stability (Shur and Jorgenson 2007). Due to these interactions, permafrost may persist in regions with a mean annual air temperature (MAAT) above 0°C and it may degrade in regions with a MAAT below -10°C (Jorgenson et al. 2010). Since permafrost dynamics are highly integral and influential to Arctic ecosystem processes, an enhanced understanding requires a multi-disciplinary approach that accounts for component couplings.
Permafrost warming, degradation, and thaw subsidence can have significant implications for ecosystems, infrastructure, and climate at local, regional, and global scales (Jorgenson et al. 2001; Nelson et al. 2001; Schuur et al. 2008). In general, permafrost in Alaska has warmed between 0.3°C and 6°C since ground temperature measurements began between the 1950s and 1980s (Romanovsky et al. 2010; Romanovsky et al. 2012). Warming and thawing of near-surface permafrost may lead to widespread terrain instability in ice-rich permafrost regions in the Arctic (Jorgenson et al. 2006; Lantz and Kokeli 2008; Gooseff et al. 2009; Balser et al. 2014; Jones et al. 2015; Liljedahl et al. 2016). Such land surface changes can impact vegetation, hydrology, terrestrial and aquatic ecosystems, and soil carbon dynamics (Grosse et al. 2011; Jorgenson et al. 2013; Kokelj et al. 2015; O’Donnell et al. 2011; Schuur et al. 2008; Vonk et al. 2015).
Thawing permafrost also interacts with changes to physical ocean conditions (sea level, storm strength and frequency, and sea ice cover) to influence coastal erosion, which can impact both ecosystems and infrastructure.
The extent and dynamics of permafrost and permafrost-related landscape features remain poorly mapped and modeled at sufficient resolution to predict impacts of climate change along a spectrum of spatial scales, which is essential for adequate understanding driving informed Arctic and global policy. Permafrost properties are linked in complex but quantifiable ways with terrain and ecosystem characteristics (Balser et al. 2015; Jorgenson et al. 2014; Mishra and Riley 2015; Pastick et al. 2014), hydrologic processes and biogeochemistry (Abbott et al. 2014; Hinzman et al. 2006; Walker and Hudson 2003) and disturbance regimes (Gooseff et al. 2009; Mack et al. 2011; Viereck 1973). Because permafrost is a subsurface property, development of geospatialdatasets suitable for modeling and scaling typically requires a well-coordinated combination of extensive field work and remote sensing analyses (Cable et al. 2016; Balser et al. 2014; Pastick et al. 2013). Rigorous examination of linkages among disciplines provides the foundation for effective modeling efforts designed to represent permafrost dynamics in local to global systems, to estimate the spatial distribution of permafrost degradation modes (Balser and Jones 2015; Olefeldt 2015; Jones et al. 2015), and to assess the vulnerability of permafrost carbon to quantify potential carbon release to the atmosphere (Schuur et al. 2015; Schuur et al. 2008).
Meeting the Permafrost Goal will require strategic and diligently executed cooperation among Federal agencies with complementary capabilities, programs, and expertise. No single agency can adequately address the gaps in scientific understanding of permafrost dynamics in a changing climate and the required improvements in empirical and modeling research to inform sound Federal policy. Additionally, collaboration with Indigenous organizations and State of Alaska Agencies could further strengthen knowledge exchange and data collection and could inform decisions. Successful development and distribution of actionable knowledge and data will come from linking specific, existing research and management programs housed within laboratories and agencies, as well as promoting and sustaining larger community initiatives and groups (such as ’s Permafrost Action Team and associated Permafrost Carbon Network), which foster synthesis studies across disciplines, provide regular meetings for sharing updates and results, and offer a forum for introduction of new ideas to the larger community. Finally, there is a need for stable, long-term observation networks coordinated across interdisciplinary research efforts and multi-agency approaches.