A little further on, on the shores of a Virginia estuary where a fort of the same name was built in 1607, an archaeologist is carrying out her excavations surrounded by sandbags.
All these remains “that we have not yet been able to study could be destroyed”, alarms Michael Lavin, director of collections at Jamestown Rediscovery, the association in charge of the site on the American east coast.
On May 4, the National Trust for Historic Preservation, a leading heritage institution, placed Jamestown on its annual list of the country’s eleven most endangered historic sites.
Faced with rising sea levels and the intensification of meteorological disturbances, a race against time has begun.
“We must act, and now,” insists Michael Lavin, 47. To get to his office, he had to ford the path, submerged.
“We have almost always known this place to be dry,” David Givens, the director of archeology who, like his colleague, has worked here for more than 20 years, told AFP. The flood of the day rose to one meter, a height of water which will be the permanent norm by the end of the century, according to an average projection.
“It’s a perfect illustration of rising sea levels, climate change and how it affects us,” continues the archaeologist. Sea levels at the mouth of the James River have already risen 45 centimeters since 1927.
The concern here is all the greater as the site is a concentrate of American history: in addition to English settlers, it welcomed Amerindian tribes for 12,000 years and, in 1619, saw the first African slaves in British North American territories.
– Bones “like sponges” –
At the foot of the old church, Caitlin Delmas scrapes the ground with her trowel. Around the archaeologist are installed sandbags and tarpaulins, deployed with each downpour. “It adds stress because we have to keep everything dry.”
Here, “almost everywhere you dig, you find something exciting,” she marvels. In 2013, the study of the bones of a young woman found there made it possible to establish, a rare fact, that she was the victim of cannibalism during a famine suffered by the colonists during the winter of 1609-1610.
But future similar discoveries may never be known: recently unearthed bones were “like sponges”, unusable due to too much dry-wet alternation.
“It’s like a war, with sandbags and trenches”, underlines David Givens, “because it is a permanent fight for us”.
“Over time, these archaeological sites will be inaccessible, eroded by seawater and flooding,” adds the 53-year-old archaeologist. “And that’s what scares me the most.”
“Cultural sites have always been affected by storms, wind, rain”, but “these forces are accelerating, intensifying, recombining” due to global warming caused by human activities, summarizes specialist Marcy Rockman, first to have considered the question within the American national parks.
In the wide estuary facing Jamestown, a handful of barges transport blocks of granite waiting for more favorable weather to reinforce the existing dike, the same one built at the beginning of the 20th century to already protect the site from the erosion.
This project at more than 2 million dollars is only a first step: against the floods, studies have been launched, and “it will cost tens of millions of dollars” warns Michael Lavin.
In Jamestown that day, the tide eased the receding waters, leaving carp splashing above the never-really excavated old cemetery, which will soon turn into a swamp if nothing is done. “Human remains are data collectors of the past,” says chief archaeologist David Givens. “It is urgent to study this”.
“We in Jamestown only have a five-year window to really limit the impacts of climate change,” warns Katherine Malone-France, chief conservation officer at the National Trust for historic preservation, in her Washington office.