Warm North Atlantic Heating Arctic

Flowing between Greenland and Norway, a North Atlantic Ocean current carrying water that is warmer than at anytime in the past 2,000 years may be speeding the decline of Arctic sea ice, scientists report.

Writing in the new issue of the journal Science, the researchers describe temperature variations derived from their study of the carbonate shells of tiny planktonic organisms in the marine sediment in the seabed of the Fram Strait off the coast of Western Svalbard.

Not only is the water the warmest its been in the past 20 centuries, report German scientist Robert F. Spielhagen and colleagues, but the flow known as the Arctic Atlantic Water Layer (AAWL) is carrying more water.

"Both effects -- a temperature rise as well as a volume transport increase -- introduce a larger heat input into the Arctic Ocean," they write. "Although there is no direct contact of the AAWL with the ocean surface in the Arctic, such an increased heat input has far-reaching consequences."

Atlantic Circulation On the Fast-track for Change

Water from the Fram Strait has warmed about 3.5 degrees Fahrenheit in the past century, a rise which Spielhagen called "significantly different from all climate variations in the last 2,000 years." Overall, air temperatures in Greenland have risen about 7 degrees F in the past several decades.

In a statement issued by the University of Colorado-Boulder, the National Snow and Ice Data Center estimates the loss of Arctic sea ice from 1979 to 2009 was an area larger than the state of Alaska.

UC researcher Thomas Marchitto, a co-author of the study, noted that cold seawater "is critical for the formation of sea ice, which helps to cool the planet by reflecting sunlight back to space.

"Sea ice also allows Arctic air temperatures to be very cold by forming an insulating blanket over the ocean," he said. "Warmer waters could lead to major sea ice loss and drastic changes for the Arctic."

The impact of these Arctic changes on weather patterns and climate changes elsewhere across the planet is a major topic of current research.

IMAGES: (Top) Courtesy of Robert Spielhagen (IFM-GEOMAR, Kiel) White shading marks average summer sea ice cover. White arrows mark ice drift motion. Red arrows mark path of warm Atlantic water entering Arctic where is submerges under the cold, ice-covered surface. The seabed sediment site is marked by the yellow spot. (Bottom) Arctic ice conditions at the end of the melt season produced from sea ice observations collected by the Advanced Microwave Scanning Radiometer (AMSR-E) Instrument on NASA's Aqua satellite overlaid on the NASA Blue Marble. Large areas of open water can be seen around the sea ice (white, image center) which stretches across the Arctic Ocean from Greenland to Russia. Credit: NASA/Corbis 2007.