January 14, 2009
Wednesday

Esook Trading Post appears as a few dots on United States Geological Survey maps of northern Alaska, but if you travel to its location today, you'll be standing in the ocean. The sea has eaten the former structures and graves that made up the turn-of-the-last-century place of business about 120 miles west of Prudhoe Bay. The demise of Esook Trading Post is a story somewhat typical of the northern coast of Alaska, where the sea is consuming land at rates among the highest in the world.

Benjamin Jones went to look for Esook Trading Post not too long ago. A research geographer with the USGS Alaska Science Center in Anchorage, Jones knew of the trading post and was curious to see if anything was left of the site, which once included five buildings and several graves with wooden markers.

Looking back over historical photos and other records, Jones found that another researcher had calculated that the trading post site had lost more than 1,200 feet to the Beaufort Sea from 1949 to 1981, when the last structure was about 60 feet from the ocean. Based on erosion rates, the last building probably disappeared in the mid-to-late 1980s, Jones said, and he didn't see any more grave markers during a snowmachine trip there in spring 2008.

The moral of this story? Don't build too close to the coastline of northern Alaska, where thawing ground makes for some of the most dynamic real estate on the planet. In a recent paper published in the journal Geophysical Research Letters, Jones and his colleagues wrote that on a section of Beaufort Sea coastline north of Teshekpuk Lake, erosion rates increased from about 20 feet per year during the 1950s to the late 1970s to about 40 feet per year during the last five years. They found the changes by comparing different eras of aerial photography of the area. Reasons they gave for the possible increase of disappearing coast included declining sea ice, warmer ocean temperatures, rising sea level, and weakening of permafrost bluffs.

"Taken together, these factors may be leading to a new regime of ocean-land interactions that are repositioning and reshaping the Arctic coastline," Jones and his coauthors wrote.

Though the acceleration of erosion rates at some areas of the northern Alaska coast may be due to forces related to a warming climate, the disappearance of the coastline has been happening for thousands of years, Jones said. Erosion of coastlines is natural, and northern Alaska is especially interesting because ice lenses and frozen ground cement much of the coast. And because the summers are so short there.

"One interesting thing to think about is that all of this erosion occurs in three to four months," Jones said.

While few people in the world will ever see Alaska's northern coast, it is the site of some of America's largest known deposits of fossil fuels. Rapid erosion since 2002 brought the sea to an oil test well drilled in the late 1970s, and the ocean will soon meet another test well near Drew Point, Jones wrote. It seems that anyone with plans to place structures in the area would do well not to ignore the impressive speed at which portions of the northern coast can become northern ocean.

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