Every year since 1978, scientists have been measuring the extent of Arctic sea ice at the end of the summer, and then comparing the ice cover from year to year. News hasn't been overwhelmingly positive of late, and while we are still waiting for this year's minimum we already know that 2009 is the third lowest year for Arctic ice extent since scientists began recording it in 1978. Over the past 20 to 30 years sea ice extent has decreased by an astounding 45,000 km each year, with 2007 holding the title for the lowest extent ever recorded, and 2008 the second lowest. Click here for National Snow and Ice Data Center images of fluctuating Arctic sea ice throughout the years. This link shows similar data from NASA.
Eric Post, associate professor of biology at Penn State University, led an international team of scientists in a survey of the Arctic ecosystem, looking at the biological response to global warming on a variety of levels ranging from changes in plants, insects, birds, mammals (including humans) and fish. The team's results will be published tomorrow in Science.
"It seems no matter where you look -- on the ground, in the air, or in the water-- we're seeing signs of rapid change,"Post said. And the changes, for the most part, are not good. Some species, such as polar bears and ringed seals, give birth in caves under the snow and in recent years have lost so many pups to early melt that they are now headed, perhaps irretrievably, to extinction.
Post's team also found animals and insects moving northward as their usual habitats warm, and decimating plant life in their wake. Winter moth, musk oxen and reindeer are eating shrubs that act as carbon sinks and help retain a thick snow cover. As the shrubs are thinned, less carbon is stored and snow melts -- contributing even further to the warming.
Caribou are also struggling, proving unsuccessful at syncing their calving cycle with the rapidly changing plant cycles. Baby caribou are born at times when there's no longer enough food around, the opportune feeding time already past. Reduction in the caribou population also further changes the hunting cycles and methods of Inuit hunters whose culture is intertwined with ice and animal behavior.
Can anything positive be gleaned from this horrible news?
If anything, it is a heartening sign that scientists have their eyes (and increasingly, the public eye) turned toward changes in the Arctic. Changes in the Inuit population's ability to hunt, as well as a dramatic shift in native culture, is increasingly being viewed as a human rights issue, and a melding of human rights with climate change brings new voices and funds to the issue. And although sea ice minimum has always been measured in September, it is perhaps a small stroke of luck that it coincides with the Senate's debate over the climate bill...we can only hope our senators are paying attention!