Created: 02/17/2014 2:17 PM WDIO.com
By: SETH BORENSTEIN, AP Science Writer
WASHINGTON (AP) - The Arctic isn't nearly as bright and white as it used to be because of more ice melting in the ocean, and that's turning out to be a global problem, a new study says.
With more dark, open water in the summer, less of the sun's heat is reflected back into space. So the entire Earth is absorbing more heat than expected, according to a study published Monday in the Proceedings of the National Academy of Sciences.
That extra absorbed energy is so big that it measures about one-quarter of the entire heat-trapping effect of carbon dioxide, said the study's lead author, Ian Eisenman, a climate scientist at the Scripps Institution of Oceanography in California.
The Arctic grew 8 percent darker between 1979 and 2011, Eisenman found, measuring how much sunlight is reflected back into space.
"Basically, it means more warming," Eisenman said in an interview.
The North Pole region is an ocean that mostly is crusted at the top with ice that shrinks in the summer and grows back in the fall. At its peak melt in September, the ice has shrunk on average by nearly 35,000 square miles - about the size of Maine - per year since 1979.
Snow-covered ice reflects several times more heat than dark, open ocean, which replaces the ice when it melts, Eisenman said.
As more summer sunlight dumps into the ocean, the water gets warmer, and it takes longer for ice to form again in the fall, Jason Box of the Geological Survey of Denmark and Greenland said in an email. He was not part of the study.
While earlier studies used computer models, Eisenman said his is the first to use satellite measurements to gauge sunlight reflection and to take into account cloud cover. The results show the darkening is as much as two to three times bigger than previous estimates, he said.
Box and University of Colorado ice scientist Waleed Abdalati, who was not part of the research, called the work important in understanding how much heat is getting trapped on Earth.
Online: PNAS journal
(Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)
Family of Duluth Stabbing Victim: 'She was Always Happy'
The family of a Duluth stabbing victim spoke out on Wednesday after the 71-year-old woman's tragic death allegedly by the hands of her own son. Mary's ex-son-in-law, Ted Beaudoin, said he's still in shock.
Duluth Police Identify 2 Suspects in Last Month's Central Hillside Shooting
The Duluth Police Department has identified two suspects they believe were involved with an August 19 shooting on the Central Hillside.
Former Teacher Pleads Guilty to Criminal Sexual Conduct Charge
A former Duluth teacher and adviser pleaded guilty to a third-degree criminal sexual conduct charge on Wednesday. The charge stems from an alleged inappropriate relationship with a student at Harbor City International School back in 2009.
Last Defendant Sentenced in 'Last Place' Case
Joseph Gellerman has been sentenced to three years' probation for his role in the sale of synthetic drugs at the former Last Place on Earth store in downtown Duluth. Gellerman is the son of store owner Jim Carlson, who is appealing after receiving a 17-year sentence.
Wilf: 'We Made a Mistake' on Peterson Decision
Vikings owner Zygi Wilf says the team "made a mistake" by bringing back Adrian Peterson following his indictment on a felony child-abuse charge in Texas. In a reversal announced early Wednesday, Peterson will not play this Sunday.