Arctic Report Card for 2011

The National Oceanic Atmospheric Administration (NOAA) just released their Arctic Report Card for 2011. The Arctic Report Card states that “[p]ersistent warming has caused dramatic changes in the Arctic Ocean and the ecosystem it supports.” Decreasing ice in the region can impact the Northern Hemisphere’s weather, and it is also resulting in a decline in polar bear activity. The minimum extent of arctic sea ice in September 2011 was the second lowest recorded since 1979. Scientists have used real-time data and analyzed the overall trends in the Arctic when putting together the research behind the disappearing ice. It is the overall trends that have scientists concerned about the arctic ice in the past decade.

Maximum sea ice extent in March 2011 (left) and minimum sea ice extent in September 2011 (right). Image Credit: National Snow and Ice Data Center Sea Ice Index
Map showing the September ice extent in 1989, 2007, 2008, 2009, 2010, and 2011. The magenta line indicates the median September ice extent for the period 1979-2000. Image Credit: National Snow and Ice Data Center Sea Ice Index:

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 overall sea ice extent has decreased over the past decade in March and September. Image Credit: NOAA Arctic Report Card

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.

Seven out of the 19 sub-populations of polar bears are declining. The image shows abundance estimates and assessments of status and trends for the 19 acknowledged sub-populations of polar bears. Image Credit: Obbard et al. 2010

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.

Mean Arctic-wide surface average temperatures from 1961-1990 have been on the increase, based on land stations north of 60° N. Image Credit: CRUTEM 3v dataset

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.

December 8, 2011

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