The White Cliffs of Dover along the southern coast of the United Kingdom are eroding. And in the past 150 years they have beat a retreat nearly 10 times hastier than they did in the previous 7,000.
The reason, researchers say, is a thinning of the beachfront separating the 90 million-year-old bluffs and the sea.
That’s the conclusion reached by a team of geologists and earth scientists from the U.S. and the U.K. who measured the cliff erosion by tracking chemical signatures in marine sediment. Writing in the journal Proceedings of the National Academy of Sciences, the scientists calculated that over the past few centuries the English Channel has eaten away at the cliffs at a rate of 8.7 inches to just over a foot inland annually. Thousands of years ago, that rate was three-quarters of an inch to 2.3 inches per year.
What has caused the beach to thin over the past 150 years may be a mixture of more powerful storms coupled with human activity. Human modification of the coastline meant, in some sections, there was a smaller beach buffer between the waves and the bluffs.
“The gravels of the beaches of the south coast were muchprized materials for a whole range of construction activities and were extracted in massive amounts over long periods,” University of Dundee geoscientist Rob Duck, who was not involved with the study, told The Guardian.