Climate change threatens archaeological heritage of coastal Georgia

A new study published February 28, 2024 in the open-access journal PLOS ONE by Matthew D. Howland of Wichita State University and Victor D. Thompson of the University of Georgia reports that thousands of historic and archaeological sites in Georgia are at risk from tropical storm surges, a number that will increase with climate change.

Due to rising sea level and increasingly severe tropical storms, human-caused climate change poses a major risk to coastlines, threatening not only living populations but also historic and archaeological sites. Mitigating damage requires accurate assessments of risks, but most predictive models focus on projected sea level rise while most physical observations focus on storm surge events. In the PLOS ONE study, Howland and Thompson use the Sea, Lake and Overland Surges from Hurricanes (SLOSH) model developed by the National Weather Service to estimate risks of storm surges along the coast of the US state of Georgia.

"The Georgia coast’s cultural heritage spans millennia, from the earliest Native American villages of Ancestral Muskogean people to its colonial missions and later plantations," said Thompson, Distinguished Research Professor and Director of the Laboratory of Archaeology in the UGA Franklin College  "These cultural sites are increasingly being impacted by storms and sea level change which threaten the material link to the broader histories of Native peoples, the enslaved, and their place in American history."

The low-lying coastal plain of Georgia hosts thousands of Native American cultural sites, historic colonial sites, and more, representing the physical cultural heritage of the region. This study finds over 4,200 such sites are potentially at risk of inundation from the storm surge of a Category 5 hurricane at present-day sea level. By the year 2100, nearly 5,000 sites could be flooded by severe hurricanes, with over 2,000 threatened by even relatively weak tropical storms. These numbers are more than ten times the estimates from previous models accounting only for sea level rise.

These results underline the importance of accounting for storm surge events along with rising sea level when assessing risks to coastal sites. The authors hope these projections will help cultural heritage managers to facilitate protection and mitigation efforts in Georgia, and they note that a similar modeling approach could be applied to coastal environments around the world.

“This study shows that the archaeological resources of the Georgia coast are at great risk of damage from potential storm surge at any time," Howland, assistant professor in the Fairmont College of Liberal Arts and Sciences at Wichita State and former Post-doctoral researcher in Thompson's lab. "Up until now, archaeologists have generally underestimated the threat to coastal cultural heritage since they have been thinking of long term averages of sea level rise rather than the kind of dramatic disaster events that can happen in Georgia and the Atlantic Coast, like Hurricane Michael in 2018.”
 

The complete study, "Modeling the potential impact of storm surge and sea level rise on coastal archaeological heritage: A case study from Georgia," is available online.
 

Image: Fig 1. from the Howland/Thompson study. Erosion at the South End site on Ossabaw Island, Georgia, caused mainly by storm surge from Hurricane Michael.