The following case study is part of a forthcoming NPS handbook on climate change entitled “Climate Change and Cultural Resources: Impact Assessments and Case Studies.” The original author is Caitlin Smith.
In the far corner of northwestern Alaska, Cape Krusenstern National Monument stands testament to some of the oldest evidence of human occupation of the North American continent. The Cape Krusenstern beach ridge complex is the most extensive in Northwest Alaska. Over 100 well preserved beach ridges reveal an unparalleled sequence of detailed evidence of an estimated 5,000 years of Inupiaq Eskimo use of the coastline relative to changes in the coastal environment and in regional patterns of climate change (Giddings and Anderson 1986). The ridges represent a valuable cultural resource at risk to coastal erosion, rising sea levels, and slumping due to permafrost thaw at rates unprecedented since human occupation of the continent (Lawler and Wesser 2010, 2).
The beach ridges of Cape Krusenstern began forming approximately 5,000 years ago during decade- to century-long periods of fair weather, and were then eroded during periods of coastal storminess. Through this action, the ridges record past fluctuations in sea level, wave energy and wave direction which helps anthropologists understand patterns of human history. The beach ridge complex forms a ‘horizontal stratigraphy’ where archeological remains date to progressively younger time periods beginning at Krusenstern Lagoon moving toward the beach (Giddings and Anderson 1986).
The ridges reveal that several stormy colder periods occurred at regular intervals at 1600-1200 BC, 100 BC-AD 300, AD 800-1050 as well as AD 1450-1800, while warm periods dominated at 2400-1600 BC and AD 300-700. Coastal sites were more intensely inhabited during the warmer periods as evidenced by archeological remains correlated to radiocarbon dated beach ridge climate data. However, the Thule culture developed during a stormy interval correlated with cooler temperatures and glacial advances, possibly accounting for their unique technological advances (Mason and Gerlach 1995, 102).
The effects of climate change are more pronounced in Alaska than any other state in the U.S. (IPCC 2007, regional impacts). Scientists anticipate increases in annual and seasonal temperatures, melting glaciers and permafrost, as well as associated changes to regional hydrology, drainage and geomorphology (Jezierski and Loehman 2010, 8) that may impact Cape Krusenstern’s cultural landscape. In particular, sea level rise and a renewed period of coastal storminess associated with climate change threaten to erode or submerge many of the precious records and resources contained in the beach ridge complex. Slumping and landslides resulting from melting permafrost also threaten to compromise the integrity of archeological sites. Recent studies at Cape Krusenstern found seven fresh landslides that result from permafrost thaw (Lawler and Wesser 2010, 2).
Cape Krusenstern’s beach ridges will continue to record this and future climate changes as they have in the past. Documentation and excavation efforts are underway to record and salvage archeological remains at Cape Krusenstern before such change irrevocably damage or washing away thousands of years of human history.
1. Anderson, Shelby. Cape Krusenstern Human-Environmental Dynamics Project- Two Hundred Years: on the beach of their time, Department of Anthropology, University of Washington/National Park Service: 2008, http://www.nps.gov/cakr/historyculture/places.htm.
2. Giddings, J. L. and D.D Anderson, Beach Ridge Archaeology of Cape Krusenstern. 1986 ed. National Park Service, Publications in Archaeology No. 20, U.S. Department of the Interior, Washington, D. C.
3. Jezierski, Caroline, Rachel Loehman, and Amanda Schramm, Understanding the science of climate change: Talking points – impacts to Alaska Boreal and Arctic. Natural Resource Report NPS/NRPC/NRR—2010/224. National Park Service: 2010, Fort Collins, Colorado.
4. Lawler, Jim and Sara Wesser, National Park Service, Alaska Region Inventory and Monitoring Program, Climate Change Resource Brief for the Arctic Network: Bering Land Bridge National Preserve, Cape Krusenstern National Monument, Noatak National Preserve, Kobuk Valley National Preserve, and Gates of the Arctic National Park and Preserve, 2010, p.1-2.
5. Mason, Owen K. and S. Craig Gerlach, “Chukchi Hotspots, Paleo-Polynas, and Caribou Crashes: Climatic and Ecological Dimensions of North Alaska Prehistory”, Arctic Anthropology vol. 32, no. 1, 1995, p. 101-130. NPS.gov, Cape Krusenstern National Monument, History and Culture, The Beach Ridges of the Cape, last modified September 22, 2010 http://www.nps.gov/cakr/details.htm