Developing Long-Term Reconstruction of Sea Level, Shoreline, and Human Settlement Change on the Northern Coast of British Columbia

Coastal societies occupy dynamic landscapes and are a part of ecosystems vulnerable to climate change. Present-day climate change is having an exacerbating effect on our coasts in the form of increasing ocean surface temperatures, sea-level rise, and increased storm events. However, many Indigenous societies thrived sustainably and resiliently in coastal settings for millennia. On the Northwest Coast of North America there is archaeological evidence for remarkably stable and persistent occupation of certain locations, even when these places transformed with changing sea levels (and, resultingly, changing local ecosystems) (Cannon 2002, 2003; Letham et al. 2017; McLaren et al. 2015; Moss 2011). Though today we face climate change at an increasing rate, understanding long-term histories of coastal changes, and the ways in which past communities were resilient is important for developing baselines for studying contemporary changes and assessing future challenges (Kirch 2005; Van der Noort 2013). This research focuses on deep-time human-environment interactions on the Northwest Coast: what are the long-term histories of RSL and shoreline change since the end of the Last Ice Age, and how and why are certain societies resilient in the face of coastal change? In partnership with Ban et al.’s MEOPAR-funded research in collaboration with the Gitga’at First Nation, Letham is employing geological and archaeological methods to reconstruct histories of RSL change from deglaciation to the present and investigating several large ancient village sites where occupation persisted through RSL changes of up to 5-10 vertical meters.