Study: Arctic getting darker, making Earth warmer

Feb 17, 2014 by Seth Borenstein
This handout photo provided by The National Oceanic and Atmospheric Administration (NOAA) shows Arctic sea ice in 2013. 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. (AP Photo/NOAA)

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, 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 , 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 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 (90,650 sq. kilometers)—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 scientist Waleed Abdalati, who was not part of the research, called the work important in understanding how much is getting trapped on Earth.

Explore further: Arctic sea ice avoids last year's record low

More information: "Observational determination of albedo decrease caused by vanishing Arctic sea ice," by Kristina Pistone, Ian Eisenman, and Veerabhadran Ramanathan. PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1318201111

add to favorites email to friend print save as pdf

Related Stories

Arctic sea ice avoids last year's record low

Oct 04, 2013

This September, sea ice covering the Arctic Ocean fell to the sixth lowest extent in the satellite record, which began in 1979. All of the seven lowest extents have occurred in the last seven years, since ...

A look back and ahead at Greenland's changing climate

Feb 06, 2014

(Phys.org) —Over the past two decades, ice loss from the Greenland Ice Sheet increased four-fold contributing to one-quarter of global sea level rise. However, the chain of events and physical processes ...

Annual Arctic sea ice less reflective than old ice

May 17, 2012

In the Arctic Ocean, the blanket of permanent sea ice is being progressively replaced by a transient winter cover. In recent years the extent of the northern ocean's ice cover has declined. The summer melt season is starting ...

Recommended for you

Sculpting tropical peaks

6 hours ago

Tropical mountain ranges erode quickly, as heavy year-round rains feed raging rivers and trigger huge, fast-moving landslides. Rapid erosion produces rugged terrain, with steep rivers running through deep ...

Volcano expert comments on Japan eruption

7 hours ago

Loÿc Vanderkluysen, PhD, who recently joined Drexel as an assistant professor in Department of Biodiversity, Earth and Environmental Science in the College of Arts and Sciences, returned Friday from fieldwork ...

NASA's HS3 looks Hurricane Edouard in the eye

20 hours ago

NASA and NOAA scientists participating in NASA's Hurricane and Severe Storms Sentinel (HS3) mission used their expert skills, combined with a bit of serendipity on Sept. 17, 2014, to guide the remotely piloted ...

User comments : 7

Adjust slider to filter visible comments by rank

Display comments: newest first

jmlvu
4.6 / 5 (11) Feb 17, 2014
We messed up the environment. Forget global warming, prepare for global fisting.
Sinister1812
4.8 / 5 (5) Feb 18, 2014
We messed up the environment. Forget global warming, prepare for global fisting.


That's true, man. Just look at the other things happening too.
runrig
4.1 / 5 (9) Feb 18, 2014
Yet another example, of where we are underestimating rather than overestimating the effects of AGW. The Arctic being particularly vulnerable to it via ice melt/albedo decreases.
FastEddy
3 / 5 (3) Feb 24, 2014
We messed up the environment. ...

What do you mean "we", stupid. G'ment is the dirtiest industry on the planet.
FastEddy
1 / 5 (3) Feb 24, 2014
Yet another example, of where we are underestimating rather than overestimating the effects of AGW. The Arctic being particularly vulnerable to it via ice melt/albedo decreases.


Never in history has raising taxes changed the weather. And since government is the dirtiest industry on the planet, increasing tax revenues to government would only produce the same: more dirt and more, not less AGW.
Maggnus
5 / 5 (1) Feb 24, 2014
We messed up the environment. ...

What do you mean "we", stupid. G'ment is the dirtiest industry on the planet.
You ever heard of "We the People" stupid? And your stupid comment about taxes is also an example of stupid people taking a stupid position on a subject they are too stupid to understand.
Captain Stumpy
5 / 5 (1) Feb 24, 2014
What do you mean "we", stupid

@FastEddy
Homo Sapiens, people, etc.
see Maggnus explanation above.
G'ment is the dirtiest industry on the planet

personal conjecture and irrelevant
Never in history has raising taxes changed the weather

personal conjecture and irrelevant
since government is the dirtiest industry on the planet, increasing tax revenues to government would only produce the same: more dirt and more, not less AGW

personal conjecture without evidence as well as irrelevant
please provide links/studies/reports/empirical data for support and relevance