Landslides Raise Fears for Britain's Cliffs of Dover
for National Geographic News
|June 14, 2001|
An unusually large stretch of Britain's famous white cliffs collapsed
recently. The loss of the quarter-mile (400-meter) section dumped a
hundred thousand tons of chalk into the sea and left many people worried
that natural erosion of the beloved landmark is occurring at an
Meanwhile, west of Dover, another landslide brought down part of the 200-foot-high (60-meter) cliff face, including the famed Devil's Chimney.
Could environmental changes caused by factors such as global warming trigger bigger and more frequent landslides?
Not so, said Steven Judd, countryside manager for the National Trust, the environmental body that owns most of the Dover coast. "I see no evidence to suggest that," he said.
The cliffs recede at an erratic rate, he said: "Averaged out over a few hundred years, the annual rate works out at only one centimeter (half an inch) a year."
Over the past year, however, Britain experienced the highest level of precipitation since record-keeping began 200 years ago. The heavy rains accelerated the erosion process dramatically, causing parts of the coast to cave in spectacularly.
While Judd views the erosion of the cliffs as natural and gradual, the collapse of large sections poses increased risks. Cliff-top structures, including lighthouses, have had to be moved to safer sites inland. And walking trails, which offer dramatic views from atop the cliffs, have been relocated farther from the crumbling edges.
Immortalized in lyrics and verse, the "White Cliffs of Dover" are an icon of English patriotism and nostalgiaa familiar landmark for returning travelers akin to the Statue of Liberty for Americans.
Facing the English Channel at the point nearest to the French coast, the 300-foot-high (90-meter-high) cliffs have also been a bastion to foreign invaders throughout history.
Before the Ice Age, Britain and France were linked by a chalk land mass. Over time, it was eroded away by tidal movements, creating the English Channel. There are matching white cliffs on the French coast.
Hidden deep underground in the white cliffs are miles of tunnels built during the Middle Ages under Dover Castle. They provided protected communication lines for garrisoned soldiers as they prepared to launch surprise attacks against enemy invasions from across the Channel.
During the Napoleonic Wars, the tunnel system was greatly expanded to fortify the castle in readiness for a French invasion. Eventually accommodating up to 2,000 soldiers, it was "the only underground barracks ever built in Britain," according to English Heritage, the official custodian of the English historic environment.
The rich history and wild beauty of the Dover cliffs has made them a popular destination for hikers and travelers. Several million are believed to visit the White Cliffs of Dover and the Seven Sisters in Brighton each year. "The walk along the cliffs, only 60 minutes from London, is very emotive and a truly marvelous experience, with the rolling chalk down land harboring numerous species of flowers, insects, and birds," said Judd.
"The scene is ever changing," he added, "with the colors of the sea varying from iridescent blues through greens and on to milky white where the dissolving chalk from rock falls stains the sea."
Wildlife will benefit from the latest massive cliff falls, according to Judd. "The landslides have opened up vast new nesting sites for sea birds returning annually to formerly overcrowded ledges on the cliff face," he said.
"Birds nesting on the cliffs include large colonies of kittiwake and increasing numbers of peregrine falcons, which were exterminated during World War II as they kept eating carrier pigeons released by secret agents from occupied France," he explained.
Although the risks for visitors are considered minimal, hikers and others are usually advised to remain at least five meters (five yards) back from the cliff edge, said Judd, who noted that visitors are more likely to be blown off the cliffs than to fall off the cliffs. Nonetheless, as an increased safety precaution during periods when rock falls are occurring more regularly, visitors are advised to stay farther back, at least 15 meters (15 yards) from the edge.
(c) 2001 National Geographic Society
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