abc
QUICK LINKS:

Study: Arctic Getting Darker, Making Earth Warmer

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 This material may not be published, broadcast, rewritten or redistributed.)

NOAA photo

Front Page

  • Superior Police: Officer's Use of Force Justified

    The Superior Police Department says an internal investigation has found an officer's use of force was justified in an arrest seen on a controversial dashcam video.  However, the officer was given a 10-hour unpaid suspension for "vulgar and unprofessional" communication during the arrest.

  • Johnston Investigation Concludes Five Allegations Substantiated

    An investigation into allegations that a Duluth school board member threatened the district's superintendent and other board members concludes that five of six claims are warranted. A 67-page report details the allegations against school board member Art Johnston released to Eyewitness News on Friday.

  • Denfeld High School Debuts In-School Food Pantry, Clothes Closet

    A new program at Denfeld High School in Duluth aimed at making sure students don't go hungry or without clothes, made its debut on Friday. The Hunter Hut food pantry and clothes closet is the first of its kind in an eight-county radius because it gives students the chance to shop for free groceries and clothing right at school....

  • Rice Lake Township Makes Moves To Become a City

    After the City of Duluth brought up the idea of annexing Rice Lake Township, township leaders are continuing their efforts to turn the township into a city. 

  • Washburn Co. Sheriff: Concrete Damaging Tires on Hwy. 53

    The Washburn County Sheriff's Office says five vehicles have suffered tire and wheel damage due to concrete problems on U.S. Highway 53.  Sheriff Terry Dryden said county highway workers are checking to see what can be done.

 
Advertisement