Arctic Region Warms into New Climate State
In 2006, the National Oceanic and Atmospheric Administration began monitoring the Arctic region, creating an annual report card to mark rapid change occurring there. Five years in and the news isn’t good.
The 2011 Arctic Report Card shows that the entire region is changing dramatically. Ice, both on land and at sea, is melting at record pace. That is upsetting the Earth’s albedo, allowing more of the sun’s energy to be absorbed by dark, open water and not be reflected back to space as it bounces off snow and ice.Sepetember 2011 saw the second lowest sea ice extent measured. The lowest was in 2007. Every year the sea ice melts more multiyear ice, which is thicker and hardier disappears. In the winter seasonal sea ice forms but it is quick to melt away the following year.
According to the report card, “The 2011 minimum is the second lowest, only 0.16 million km2 greater than the 2007 record minimum.” Overall, the 2011 minimum reached on September 9 was 31% (2.08 million km2) smaller than the 1979-2000 average. The report says, “The last five summers (2007-2011) have experienced the five lowest minima in the satellite record, and the past decade (2002-2011) has experienced nine of the ten lowest minima.”
All of the newly exposed water is allowing atmospheric carbon dioxide to sink into the Arctic waters and it is changing the chemical makeup of the ocean. As a result, the Chukchi and Beaufort seas have lower pH values. In other words the waters are becoming more acidic, which makes it difficult for tiny sea animals that rely on calcium carbonate shells to survive. The higher acid level makes shell formation more difficult.
The report card says, “The increased amount of open water enhanced the uptake of CO2 from the atmosphere and the freshening of the upper ocean decreased alkalinity, inorganic carbon and calcium ion concentrations.” The melting sea ice exposed more water to the open air, allowing more atmospheric carbon dioxide to sink in the ocean, making the ocean more acidic. The report notes, “Although CO2 concentration in surface waters in 2010 and 2011 was not as high as in 2008, these waters have continued to be undersaturated with respect to aragonite.” By monitoring the aragonite levels scientists can determine if phytoplankton is having trouble forming shells.
In addition to watching the ocean and the atmosphere change, NOAA also monitors shorter term weather patterns and tracks the impact they have on the Arctic region as a whole. And the last few years, pressure over the North Pole shifted, pushing the coldest Arctic air far south to the United States and Europe while warmer air filtered over Greenland, rapidly speeding up the melt rate of glaciers there.
For the first time, the 2011 Arctic Report Card measured changes in Greenland. As a result of the North Atlantic Oscillation (NAO) switching from positive to negative, caused unusually warm weather during Winter 2010-2011 and last summer. Those weather conditions in turn sped up the melt rate from the Greenland ice sheet.
The report says, “The area and duration of melting at the surface of the ice sheet in summer 2011 were the third highest since 1979.” According to satellite data, the Greenland ice sheet melted to its third lowest point since 1979 when record keeping began. Only 2010 and 2007 exceeded that ice loss.
NOAA principal deputy under secretary of commerce for oceans and atmosphere Monica Medina says, “This report, by a team of 121 scientists from around the globe, concludes that the Arctic region continues to warm, with less sea ice and greater green vegetation.”
Using a familiar image of a stoplight, NOAA classified the five chapters of the report card according to level of change. The findings show that Atmosphere, Sea Ice & Ocean, Hydrology & Terrestrial Cryosphere have experienced significant change while Marine Ecosystems and Terrestrial Ecosystems have experienced some change. No coverage area received a greenlight, meaning little or no change.
The Report Card tracks the Arctic atmosphere, sea ice, biology, ocean, land, and Greenland. This year, new sections were added, including, greenhouse gases, ozone and ultraviolet radiation, ocean acidification, Arctic Ocean primary productivity, and lake ice.
It concludes, “Sea ice and ocean observations over the past decade (2001-2011) suggest that the Arctic Ocean climate has reached a new state, with characteristics different than those observed previously.”
And, “In 2011 there was continued widespread warming in the Arctic, where deviations from historical air temperatures are amplified by a factor of two or more relative to lower latitudes. This phenomenon, called Arctic Amplification, is primarily a consequence of increased summer sea ice loss and northward transport of heat by the atmosphere and ocean.”