Philadelphia — After two decades of concern that the melting ice sheet in Antarctica may fall into the ocean and create catastrophic global flooding, scientists now say the ice is growing thicker.
They are not yet sure how to interpret the reverse in what has been a 10,000-year thinning trend, though they suggest the changes are not directly linked to global warming and human-generated pollutants.
The surprise finding, published in Friday's issue of the journal Science, was made with the help of a Canadian mapping satellite. The satellite used radar to monitor changes in the ice sheet, which is two-thirds of a mile thick and stretches over an area of western Antarctica that is more than half the size of the United States.
Ice leaves the ice sheets by flowing down solid "ice streams", said one of the paper's authors, Ian Joughin of the Jet Propulsion Laboratory in Pasadena, Calif. These flow like very slow rivers, he said, moving about a quarter mile per year and conveying ice from the continent to the coast, where pieces break off and float away as icebergs.
By analyzing satellite images, Joughin found that the ice streams have slowed in the last two decades, and one of the major ones stopped. Currently, snow is piling up on top of the ice sheet faster than the streams are taking it away, he said.
While it was thought to be losing 20 billion tons of ice a year, he said, it's actually gaining 26 billion tons.
No comments
Commenting is turned off for this story.