Tropical Cyclones Wash Away Carbon

Hurricanes and typhoons, normally seen as looming threats from global warming, are actually helping to remove carbon dioxide from the atmosphere.

Each year humans emit approximately 7.2 billion tons of the greenhouse gas, trapping vast amounts of heat in the air and oceans. Tropical cyclones derive their energy from warm seas, and some scientists believe global warming will spawn more frequent and more intense storms unless drastic effort is undertaken to cut emissions.

But Robert Hilton of the University of Cambridge in the United Kingdom and a team of researchers found that when two powerful storms lashed Taiwan in 2004, rains eroded thousands of tons of carbon-rich plant matter and soil. The material was sent coursing out of the island's steep mountain range down the LiWu River and into the deep sea, where it was buried in sediment.

"Over the last 30 years large storms, which only last a few days, dominated the erosion there," Hilton said. "Between 77 and 92 percent of carbon was eroded by these storms."Globally, rivers slough vast amounts of carbon off continents and into the oceans. The Amazon River, the largest in the world by volume, dumps an estimated 13 million tons of carbon into the sea each year.