BORTH, WALES — There is a poem children in Wales learn about the sunken kingdom of Cantre’r Gwaelod, swallowed by the sea and drowned forever after. On a quiet night, legend has it, one can hear the kingdom’s church bells ringing.
When the sea swallowed part of Britain’s western coastline this year and then spat it out again, leaving homes and livelihoods destroyed but also a dense forest of prehistoric tree stumps more exposed than ever, it was as if one had caught a faint glimpse of that Welsh Atlantis.
The submerged forest of Borth is not new. First flooded some 5,000 years ago by rising sea levels after the last ice age, it has been there as long as locals remember, coming and going with the tides and occasionally disappearing under the sand for years on end. But the floods and storms that battered Britain earlier this year radically changed the way archaeologists interpret the landscape: A quarter-mile-long saltwater channel cutting through the trees, revealed by erosion for the first time, provided a trove of clues to where human life may have been concentrated and where its traces may yet be found.
“We used to think of this as just as an impenetrable forest — actually this was a complex human environment,” said Martin Bates, a geoarchaeologist at the University of Wales Trinity St. David, who oversees the excavation work in Borth on a beach he played on as a toddler. “The floods have opened our eyes as to what’s really out there.”
Scanning the army of ghostly spikes protruding from the sand here one recent morning, Dr. Bates said it was as if nature were making a point: The recent torrential rains, linked by a growing number of climatologists to human-induced climate change, have provided an ancient laboratory to study how humans coped with catastrophic climate change in the past.
Indeed, across Britain, two consecutive years of exceptional winter weather have left in their wake some equally exceptional discoveries: from unexploded wartime bombs and Victorian shipwrecks to archaeological finds that are nearly a million years old. Scientists have barely kept up. Last winter was the wettest on record, according to the Met Office, the national weather service.
Dog walkers and amateur archaeologists are being sought in ever-greater numbers to help record new sites. In some areas hit especially hard by erosion, locals are equipped with cameras that log digital images with geocoordinates so the artifacts they find on beach walks can be added to national databases.
“Archaeologists can’t be everywhere, but locals can,” said Erin Kavanagh, Dr. Bates’s partner and a fellow archaeologist.
Nicholas Ashton, the curator of Paleolithic and Mesolithic collections at the British Museum, has been organizing “fossil road shows” in which he invites civilians to bring in any potential archaeological finds and have them identified. (One man recently showed up with a six-inch-long hippo tusk and a well-preserved ax, both found locally and both more than half a million years old.)
Having those extra eyes on the ground can make all the difference in coastal areas, Dr. Ashton said, for what the sea reveals, it tends to reclaim almost as soon. He learned this lesson firsthand.
In May 2013, shortly after the first set of storms, Dr. Ashton commissioned Dr. Bates, an old university friend, to work on Britain’s east coast in Norfolk. The beach near Happisburgh (pronounced hays-boro), a longstanding archaeological site, had suffered severe erosion. Dr. Ashton, an expert in early humans, wanted a geophysical survey to map any channels or rivers that might lie beneath about 30 feet of sediment. Some of these channels, he reckoned, might contain evidence of early humans because sources of freshwater would have been natural gathering spots.
It was on their second visit, on May 10, that Dr. Bates noticed some indentions on the otherwise flat horizons of the laminated silts recently laid bare on the beach. The humps and bumps looked familiar. He told Dr. Ashton: “They’re just like the human footprints in Borth.”
Footprints of humans and animals in Borth had been dated to about 6,000 years ago. The site in Happisburgh was 900,000 years old, a time when mammoths and hippos still roamed in these parts. No human bones or prints that old had ever been found in Britain.
Could this be possible?
A frantic race against time began. Every day, the shape of the prints would blur a little more as the coming tide eroded the contours of heels, toes and arches. A team led by Sarah Duffy from the University of York arrived to apply a technique called multi-image photogrammetry, taking about 150 digital photographs of the surface area containing the prints and feeding it into a program that created a three-dimensional model. By the time another team had come to do some laser scanning, it was too late: The prints were barely visible.
Panicked, scientists lifted from the site a 130-pound block of sediment with one faint print on top, to have it analyzed at the National Oceanography Center. It is the only remaining physical evidence of the footprints: Before the month was out, all traces of them had vanished. It was a powerful reminder of both the resilience and the fragility of human life.
“What had been preserved for nearly one million years was taken back by the sea in the space of 10 days,” Dr. Ashton said.
Initially skeptical, he said he knew the footprints were real when Dr. Duffy’s computer images landed in his inbox sometime last June. “I thought, bloody hell, we are dealing with something quite extraordinary here,” he said.
The footprints, the oldest known outside Africa, probably belonged to a family group of Homo antecessor, a cousin of Homo erectus that possibly became extinct when Homo heidelbergensis from Africa settled in Britain about 500,000 years ago, he said. Using foot-length-to-stature ratios, scientists estimate that the male was perhaps 5 feet 9 inches tall, and the smallest child a little less than 37 inches.
Little is known about this early human species. Fossil skeletons in Atapuerca, Spain, from around the same time suggest that they walked upright and looked much like modern humans, though their brains were smaller. If they had language, it was primitive. Living at the tail end of an interglacial era, as winters were growing colder, they may have had functional body hair. So far, there is no evidence that they used clothes, shelter, fire or tools more complex than simple stone flakes...