Ice in the Arctic moves through cycles each year. During the winter months, ice accumulation begins in October and November and continues through March. March is typically the month where we see the winter maximum sea ice extent. During spring and summer, the ice that grew during the winter months begins to melt, and ice accumulations shrink. This is a process that continues every year. The growth of ice is always expected in the winter months. However, it is the overall trends that are alarming. During the past decade, sea ice extent has slowly decreased (see image below). The sea ice extent for September 2011 was the second lowest recorded, with 4.33 million square kilometers. The lowest sea ice extent ever recorded was in 2007. The 2011 minimum was 31 percent smaller than the 1979-2000 average. The Northwest Passage southern route, Northwest Passage northern route, and the northern sea route across the Siberian coast are typically closed with ice, meaning the route is not ice-free. Ice extent at these passages is determined with passive microwave imagery. Since 2010, all three passages have been ice-free.
Note: snow and ice have a high albedo, which means that a lot of solar energy from the sun is reflected back into space. Surfaces with high albedo slow melting because the energy added into the system is typically reflected away into space. However, with the ice melting, ocean water has been exposed. Ocean surfaces are darker, and darker surfaces have lower albedos, meaning more solar energy is being absorbed. The more energy that is being absorbed means an increase of heat to further intensify the melting of the ice cap.
The melting ice in the Arctic has huge ramifications for wildlife and living species. For instance, phytoplankton production has increased to around 20 percent from 1998 to 2009 across the eastern Arctic Ocean. Phytoplankton are simply microscopic plants that live in the sunlit top layers of water. They use sunlight and nutrients to grow, and a lot of their nutrients come from melting ice that produces freshwater. Vegetation has increased since satellite observations have been made from 1982 to 2010. An increase in vegetation shows less ice and higher land temperatures across the Arctic. Polar bears are also affected by the melting of sea ice. The 2011 report states that “7 of 19 of the world’s polar bear sub-populations are found to [be] declining in number, with trends in two linked to reductions in sea ice.” Polar bears use sea ice to hunt, mate, travel, and den. Smaller ice caps mean less prey for the polar bears, which could affect their growth, production, and overall survival in the Arctic.
The melting of the ice caps results in changes in the weather as well. The Arctic Report Card states that “unusually strong north and south winds in fall and winter resulted in an Arctic-wide pattern of impacts, with warmer than normal temperatures of several °C over Baffin Bay/west Greenland and Bering Strait, and cooler temperatures over NW Canada and northern Europe.” The report also states that “with future loss of sea ice, such conditions as winter 2009-2010 could happen more often. Thus we have a potential climate change paradox. Rather than a general warming everywhere, the loss of sea ice and a warmer Arctic can increase the impact of the Arctic on lower latitudes, bringing colder weather to southern locations.” Remember the giant storm that hit Alaska on November 8, 2011? The lack of ice in the Alaska region was a huge concern because it would increase the storm surge from the approaching cyclone. If ice was already there, then storm surge and coastal flooding would not have been as significant.
Where does all of the scientific information for the Arctic report come from? I find the following very important because it has been peer-reviewed with many researchers at the helm:
The Arctic Report Card reflects the work of an international team of 121 researchers in 14 countries and is based upon published and ongoing scientific research. Peer-review of the scientific content of the report card was facilitated by the Arctic Monitoring and Assessment (AMAP) Program. The Circumpolar Biodiversity Monitoring Program (CBMP), the cornerstone program of the Arctic Council’s Conservation of Arctic Flora and Fauna (CAFF) Working Group, provides leadership on the biodiversity elements of the report card. The Report Card is led by an inter-agency team from NOAA, the Cold Regions Research and Engineering Laboratory and the Office of Naval Research. Support for the Arctic Report Card is provided by the NOAA Climate Program Office through the Arctic Research Program.
Bottom line: Persistent warming has caused dramatic changes in the Arctic Ocean and the ecosystem it supports. Melting ice caps support more phytoplankton, algae and vegetation. Meanwhile, it can disrupt and hurt polar bear populations. Melting ice caps can affect the winters in the Northern Hemisphere, with warming temperatures in the Arctic and colder air pushing south. Of course, weather patterns have a huge influence of where the cold air moves south. For instance, the pattern we are currently in has been providing cold air west of the Mississippi River and mild weather across the eastern third of the United States. The report shows a persistent decline in the thickness and summer extent of the sea ice cover and the addition of a warmer and fresher upper ocean. Sea ice extent was the second lowest recorded in September 2011, and the trends show that changes will continue through time. For more information regarding the 2011 Arctic Report Card, check out NOAA’s page here.
Matt Daniel is weekend Meteorologist for 13WMAZ (CBS) in Macon, Georgia, and founder of the blog Athens GA Weather. He's a self-described "big weather and music geek" and has produced weather content for CNN, MSN Weather and EarthSky. He has a passion for helping to keep people safe when severe weather strikes and says if you don't have a NOAA Weather Radio ... you should get one.