Humans said have huge impact on erosion

updated 7:14 p.m. ET Dec. 1, 2006

SYRACUSE, N.Y. - Mother Nature may be a force, but nothing like humans when it comes to causing erosion, says a Syracuse University scientist.

Humans cause erosion at a rate 10 to 15 times faster than any natural process, according to new research by Bruce Wilkinson, a sedimentary geologist.

Scientists have long identified humans as the primary agents altering the shape of the Earth's surface. Wilkinson said his study gauged the rate of man-made erosion and compared the speeds and differences under which natural and human-related erosion occur.

By using data gathered from around the world and the universal soil loss equation, Wilkinson determined that global erosion is occurring at a rate of about 75 gigatons a year — a gigaton is equal to a billion tons.

"To put that into context," Wilkinson said, "current annual amounts of rock and soil moved over the Earth's surface in response to human activities are ... an amount of material that would fill the Grand Canyon of Arizona in about 50 years."

Wilkinson presented his findings at the 118th annual meeting of the Geological Society of America, held in late October in Philadelphia. His paper, titled "The impact of humans on continental erosion and sedimentation," will be featured in the January-February issue of the Geological Society of America's GSA Bulletin.

Roger LeBaron Hooke, a prominent researcher now at the University of Maine in Orono, first wrote a decade ago about the impact of humans as the most potent force in shaping the planet.

At that time, Hooke estimated humans moved about 45 gigatons of sediment annually, but he looked only at construction and mining, but did not include agriculture.

Hooke "basically agreed" with Wilkinson's results, although he said the study underplayed the impact of precipitation in natural erosion.

Before humans began moving earth, wind, water and glaciers accounted for most erosion.

But nature was in no hurry. The movement of sediment took millions of years.

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