Artist’s re-creation of the first human migration to North America from across the Bering Sea
[Credit: DEA Picture Library/Deagostini/Getty Images]
Today, sea-level rise is a great concern of humanity as climate change warms the planet and melts ice sheets in Greenland and Antarctica. Indeed, great coastal cities around the world like Miami and New Orleans could be underwater later in this century. But oceans have been rising for thousands of years, and this isn't the first time they have claimed land once settled by people. A new paper published in Geographical Review shows evidence vital to understanding human prehistory beneath the seas in places that were dry during the Last Glacial Maximum. Indeed, this paper informs one of the "hottest mysteries" in science: the debate over when the first Asians peopled North America.
The researchers behind the paper studied "choke points" -- narrow land corridors, called isthmuses but often better known for the canals that cross them, or constricted ocean passages, called straits. Typically isthmuses would have been wider 20,000 years ago due to lower sea levels, and some straits did not even exist back then.
"We looked at nine global choke points -- Bering Strait, Isthmus of Panama, Bosporus and Dardanelles, Strait of Gibraltar, straits of Sicily and Messina, Isthmus of Suez, Bab al Mandab, Strait of Hormuz and Strait of Malacca -- to see what each was like 20,000 years ago when more water was tied up in ice sheets and glaciers," said lead author Jerry Dobson, professor emeritus of geography at the University of Kansas and president emeritus of the American Geographical Society. "During the Last Glacial Maximum, the ocean surface was 410 feet lower than today. So, worldwide the amount of land that has been lost since the glaciers melted is equivalent to South America."
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