Recent climate warming and scenarios for further warming have led to expectations of rapid movement of ecological boundaries. Here we focus on the circumarctic forest–tundra ecotone (FTE), which represents an important bioclimatic zone with feedbacks from forest advance and corresponding tundra disappearance (up to 50% loss predicted this century) driving widespread ecological and climatic changes. We address FTE advance and climate history relations over the 20th century, using FTE response data from 151 sites across the circumarctic area and site‐specific climate data. Specifically, we investigate spatial uniformity of FTE advance, statistical associations with 20th century climate trends, and whether advance rates match climate change velocities (CCVs). Study sites diverged into four regions (Eastern Canada; Central and Western Canada and Alaska; Siberia; and Western Eurasia) based on their climate history, although all were characterized by similar qualitative patterns of behaviour (with about half of the sites showing advancing behaviour). The main associations between climate trend variables and behaviour indicate the importance of precipitation rather than temperature for both qualitative and quantitative behaviours, and the importance of non‐growing season as well as growing season months. Poleward latitudinal advance rates differed significantly among regions, being smallest in Eastern Canada (~10 m/year) and largest in Western Eurasia (~100 m/year). These rates were 1–2 orders of magnitude smaller than expected if vegetation distribution remained in equilibrium with climate. The many biotic and abiotic factors influencing FTE behaviour make poleward advance rates matching predicted 21st century CCVs (~103–104 m/year) unlikely. The lack of empirical evidence for swift forest relocation and the discrepancy between CCV and FTE response contradict equilibrium model‐based assumptions and warrant caution when assessing global‐change‐related biotic and abiotic implications, including land–atmosphere feedbacks and carbon sequestration.

Coseismic landslides represent a major cascading hazard associated with high-magnitude earthquakes in mountainous environments (Fan, Scaringi, Domènech, et al., 2019; Fan, Scaringi, Korup, et al., 2019). The widespread landsliding observed in many recent large continental earthquakes has led to substantially higher death tolls when compared to earthquakes without landslides (Budimir et al., 2014), disruption to infrastructure (Aydin et al., 2018; Bird & Bommer, 2004), and the mobilization and transport of large volumes of sediment (M. Y. F. Huang & Montgomery, 2012; Wang et al., 2015). Increased interest in understanding the spatial distribution, impacts, and timing of coseismic landslides in recent decades has resulted in the production of a growing number of coseismic landslide inventories (Tanyas et al., 2017). In contrast, despite growing evidence for the persistence of enhanced landslide rates and the consequent long-term impacts of coseismic hillslope damage in the years to decades after a major earthquake (e.g., Dadson et al., 2004; Hovius et al., 2011; Marc et al., 2015; Parker et al., 2015), our current understanding of the post-seismic evolution of landslides is limited. As a result, we remain incapable of anticipating the spatio-temporal evolution of landslide hazard after a large earthquake, which frustrates our ability to inform response, recovery, and reconstruction (e.g., Robinson et al., 2017; Williams et al., 2018), and limits understanding of the long-term role of earthquakes in the overall mountain sediment cascade. A standard approach to tracking post-seismic landsliding is to develop multi-temporal landslide inventories, usually by mapping from airborne or satellite imagery. This is a time-consuming and potentially expensive Abstract Coseismic landslides are a major hazard associated with large earthquakes in mountainous regions. Despite growing evidence for their widespread impacts and persistence, current understanding of the evolution of landsliding over time after large earthquakes, the hazard that these landslides pose, and their role in the mountain sediment cascade remains limited. To address this, we present the first systematic multi-temporal landslide inventory to span the full rupture area of a large continental earthquake across the pre-, co-and post-seismic periods. We focus on the 3.5 years after the 2015 M w 7.8 Gorkha earthquake in Nepal and show that throughout this period both the number and area of mapped landslides have remained higher than on the day of the earthquake itself. We document systematic upslope and northward shifts in the density of landsliding through time. Areas where landslides have persisted tend to cluster in space, but those areas that have returned to pre-earthquake conditions are more dispersed. While both pre-and coseismic landslide locations tend to persist within mapped postearthquake inventories, a wider population of newly activated but spatially dispersed landslides has developed after the earthquake. This is particularly important for post-earth...