History sinks beneath the waves

Rising sea levels brought about by climate change have been shown to threaten catastrophic destruction to communities and entire nations around the globe. But a new study suggests that a great deal of human archaeological history may also be lost. 

Focusing on the Atlantic and Gulf coasts of the south-eastern United States, the study published in the open-access journal PLOS ONE says sea-level rise may affect “vast numbers of archaeological and historic sites, cemeteries, and landscapes” in these regions.

Just in the remainder of this century, if projected trends in sea-level rise continue, the researchers, led by David Anderson from the University of Tennessee, predict that more than 13,000 recorded archaeological sites in the US south-east alone may be submerged, including more than 1000 listed on the National Register of Historic Places as important cultural properties. Many more sites and structures that have not yet been recorded will also be lost.

To estimate the impact of sea-level rise on archaeological sites, Anderson’s team analysed data from the Digital Index of North American Archaeology (DINAA), a research organisation that aggregates archaeological and historical information developed over the past century from numerous sources, providing resources for public and academic purposes.

Anderson explains that the work of organisations such as DINAA is essential to preserve knowledge and information once the physical structures and materials are lost. 

“Sea-level rise in the coming years will destroy vast numbers of archaeological sites, buildings, cemeteries, and cultural landscapes,” he says. “Developing informatics capabilities at regional and continental scales like DINAA is essential if we are to effectively plan for, and help mitigate, this loss of human history.”

The report says such research is essential for making accurate forecasts and public policy decisions about the consequences of rapid climate change, extreme weather events, and displaced populations. 

“These are factors that could shape our civilisation profoundly in the years to come,” the authors state.

The threat to a country such as Australia is equally profound, a CSIRO and Antarctic Climate and the Ecosystems Cooperative Research Centre study for the Department of Environment and Energy points out.

Looking to 2100, it says that, on average, Australia will experience a roughly 300-fold increase in flooding events, meaning that infrastructure of high economic, social and environmental value that is at present flooded once in a century will be flooded several times per year, assuming a sea level rise of 50cm.

The concern is, of course, widespread. In February, in the journal Quaternary Science Reviews, Italian researchers published a report titled Sea-level rise and potential drowning of the Italian coastal plains: Flooding risk scenarios for 2100.

It says the expected sea-level rise by 2100 will change dramatically the present-day landscape, potentially flooding up to about 5500 square kilometres of Italy’s coastal plains at elevations close to present-day sea level.

The subsequent loss of land will affect the environment and local infrastructures, the report says, while also urging decision-makers to “take into account these scenarios for a cognisant coastal management”.