Bellwether sites for evaluating changes in landslide frequency and magnitude in cryospheric mountainous terrain: a call
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Jeffrey A. Coe
Bellwether sites for evaluating changes in landslide frequency and magnitude in cryospheric mountainous terrain: a call for systematic, long-term observations to decipher the impact of climate change
Abstract Permafrost and glaciers are being degraded by the warming effects of climate change. The impact that this degradation has on slope stability in mountainous terrain is the subject of ongoing research efforts. The relatively new availability of highresolution (≤ 10 m) imagery with worldwide coverage and short (≤ 30 days) repeat acquisition times, as well as the emerging field of environmental seismology, presents opportunities for making remote, systematic observations of landslides in cryospheric mountainous terrain. I reviewed the literature and evaluated landslide activity in existing imagery to select five ~ 5000-km2 sites where long-term, systematic observations could take place. The five proposed sites are the northern and eastern flanks of the Northern Patagonia Ice Field, the Western European Alps, the eastern Karakoram Range in the Himalayan Mountains, the Southern Alps of New Zealand, and the Fairweather Range in Southeast Alaska. Systematic observations of landslide occurrence, triggers, size, and travel distance at these sites, especially if coupled with observations from in situ instrumental monitoring, could lead to a better understanding of changes in slope stability induced by climate change. The suggested sites are not meant to be absolute and unalterable. Rather, they are intended as a starting point and discussion starter for new work in this expanding landslide research frontier. Keywords Climate change . Landslide . Rock avalanche . Rock fall . Debris flow . Frequency . Magnitude . Mobility . Hazard . Permafrost . Glacial retreat . Air temperature . Satellite imagery . Landsat . Sentinel . NISAR . Seismology . Monitoring Introduction Where should landslide researchers look for changes in slope stability induced by a warming climate? The most straightforward answer, which has been recognized since at least 1990 (e.g., Slaymaker 1990; Haeberli and Beniston 1998; Geertsema et al. 2006; Gruber and Haeberli 2007; Coe and Godt 2012; Huggel et al. 2012; Deline et al. 2015a; Gariano and Guzzetti 2016), is steep-cryospheric terrain in mountainous regions of the world because ice (either in permafrost or glaciers) in these areas is being degraded and reduced by warming temperatures (e.g., Paul et al. 2004; Harris et al. 2009; Huss and Hock 2015; Pastick et al. 2015; Kos et al. 2016; Zemp et al. 2019; Hock et al. 2020). An added benefit to these areas is that landslides are unlikely to be influenced by land use changes brought on by climate change. Land use changes by themselves can alter the frequency and magnitude of landslides (Sidle and Burt 2009; Petley 2010; Crozier 2010; Wasowski et al. 2010). About 10% of the worldwide populace lives in mountainous regions that are susceptible to hazards resulting from a degrading
cryosphere (Hock et al. 2020). The loss of ice in these regions
