We are losing sea ice cover in the Arctic at a rapid pace that has even surprised scientists. According to the National Snow and Ice Data Center (NSIDC), the March 2009 arctic sea ice extent was 590,000 square kilometers below the 1979-2000 average. Over the past 6 years, arctic ice cover and thickness has been plummeting, and many of the leading scientific experts who study sea ice predict a seasonally ice-free Arctic Ocean may be realized as early as 2030. This dramatic loss of sea ice is the result of the rapid climate change occurring in the Arctic.
To make matters worse, the loss of sea ice is almost certainly speeding up warming in the Arctic. Sea ice reflects about 50-90% of the sunlight that hits it. This is in contrast to the open water, which only reflects about 10-15% of the sunlight that strikes it. With less ice more solar radiation is absorbed by the ocean, which otherwise would have been reflected back into space. With the loss of sea ice cover a lot more sunlight is being absorbed and heating the Arctic Ocean.
In addition to the decline of sea ice cover, remaining ice is thinner. Much of the older thicker sea ice has been replaced by younger thinner sea ice. During March 2009 about 10% of the Arctic sea ice was made up of thicker multi-year ice – down 30% from the recorded average for March. Multi-year ice is ice that has not melted over several years and tends to get thicker each year, making it less likely to melt during the summer. The loss of the older thicker ice makes it more likely that an unusually warm summer will melt more of the ice cover and result in a further precipitous decline of sea ice cover.
About four million people live in the Arctic, and they are the first to feel the impacts of rapid climate change. Communities are threatened by coastal erosion, as the sea ice that used to protect their shores from storm waves is no longer there. The thinning ice is also making travel much riskier for Arctic peoples who use it to travel from place to place.
The loss of sea ice is predicted to be devastating to arctic ecosystems. For example, algae (marine plants) growing within channels and on the bottom of sea ice serve as the base of an ice associated food-web. Many Arctic marine mammals (seals, walruses, and polar bears) seabirds and fish hunt, breed, and feed on or under the sea ice. The loss of sea ice cover is a threat to many species, the health of Arctic ecosystems, and opportunities for the subsistence way of life of Arctic peoples.
Changes in sea ice cover are likely to be felt around the world. For example, the Arctic plays an important role in the functioning of the global climate system, acting as a refrigerator for the planet. As sea ice declines the Arctic will warm rapidly, and this warming is predicted to affect weather patterns across the northern Hemisphere.
The rapid loss of Arctic sea ice is raising a huge red flag about climate change, and the dramatic impacts that may be coming to our own backyards if we don’t act soon. As all of us have a stake in the health of the planet, we all have a stake in the health of the Arctic.