Climate change threatens to destroy over 20,000 historical sites, archaeologists say
30 November 2017 | Adaptation
Thanks to climate change, a predicted rise in sea level along the Atlantic and Gulf coasts of the southeastern U.S. over the next century or two is currently modeled at a seemingly modest one to two meters. This change in the coastline, however, threatens tens of thousands of known archaeological sites, standing historic and prehistoric structures, and other cultural properties, according to archaeologists.
Writing today in PLOS One, a team composed of nine archaeologists from around the U.S. detail their model of cultural resources most at risk should the sea level rise predicted to result from anthropogenic global climate change bear out. The researchers used data accessible through the Digital Index of North American Archaeology (DINAA), a database whose current coverage is best in the swath of land from Maryland to the Texas-Louisiana border.
Along this coastline, the archaeologists discovered that 5,762 archaeological sites are already at or below sea level, while a total of 32,898 are at or below 5 m above sea level. "Assuming current projections hold," David G. Anderson of the University of Tennessee, Knoxville and colleagues write, "and the sea level rises approximately one meter by the end of the century, a total of 19,676 currently recorded archaeological sites will be submerged." Especially problematic is the "loss of a substantial portion of the record of both pre-Columbian and historic period human habitation of the coastal margin of the southeastern United States."
Site incidence as it relates to potential loss from sea-level rise, grouped by elevation in meters above present mean sea level.
Archaeological sites are not the only casualties of sea level rise. The researchers note that "the dead as well as the living will also be impacted." Historical cemeteries are not recorded in the same way that archaeological sites are, so the archaeologists can only estimate the impact of climate change on graveyards: close to 7,000 are mentioned in the DINAA data over 15 southeastern states, representing the lower bound of the number of cemeteries at risk.
One of the states projected to be hardest hit by climate change is Florida, simply because of the amount of coastline. Fortunately, the state is also home to the Florida Public Archaeology Network, whose mission is to promote and facilitate conservation, study, and public understanding of the archaeological heritage of Florida. FPAN's Northeast Regional Director, archaeologist Sarah Miller, is also the program manager for Heritage Monitoring Scouts (HMS) of Florida.
Miller praised the data produced by Anderson and colleagues, noting that "baseline numbers are essential to defining the problem." But the public, she says, is often inundated with numbers without being given opportunities to help. HMS Florida is a "citizen-science initiative by FPAN to monitor close to 4,000 archaeological sites at risk from sea level rise," Miller explains. "In just over a year, 296 citizen-science volunteers signed up across Florida. At this rate, we have the potential to document and assess these archaeological sites within ten years' time."
But Florida is only one state. Anderson says that "the cooperation of large numbers of people and organizations - a truly team effort - is needed if we are to protect our history." He and his co-authors argue that "one way to do that, an important first step, is to have a good handle on what may be threatened or lost. Projects like DINAA provide tools useful for public education, resource management, and research projects."
Although DINAA is only focused on the southeast, Anderson and colleagues have already begun to reach out to preservation authorities in every state. "Aggregating and integrating these data," co-author Eric Kansa, Program Director for Open Context, says, "requires expert labor. It doesn't just happen, and it takes time to reach a 'critical mass' of relevant data that can enable new research." What's unique about DINAA, though, is that it is all open source. "We would love to see people build alternative user interfaces that meet different needs for different applications and different communities," Kansa insists. "Collaboration between data experts and public engagement experts will also be critical."
When asked what the models will look like if and when additional states' data are compiled into DINAA, Anderson commented that "the picture is unlikely to look very good anywhere, since people have been living in coastal areas for millennia." Peninsular Florida will be particularly hard hit by sea level rise, but large coastal states like Texas and California will likely also see climate change that will be catastrophic to historic and prehistoric archaeological sites. However, depending on the rate of sea level rise, the archaeologists note, climate change may only submerge these resources, and the extent of damage, destruction, or loss is still uncertain.
Mitigating damage to the cultural history of the United States will therefore take effort at numerous levels. Miller notes that programs such as Florida's HMS exist in other countries and are emerging in other states now. "In the near future," she says, "I hope there will be more regional and national coordination of outreach efforts by archaeologists to pool the limited resources for public engagement into increased community action."
Ultimately, Anderson and colleagues write in their PLOS article, "what will be needed is a commitment, like that last seen in the Great Depression, to document that which will be lost if the effects of sea level rise are not mitigated. Tools like DINAA are the future of archaeological research, and it is not a question of if they will be developed, but when."