The figure on the right shows the yearly total area coverage of sea ice in the Arctic Ocean (y-axis), as a function of month of the year (x-axis). 2008 has had more sea ice coverage than in 2007, especially in the summer months, but is significantly below average. Image from the National Snow and Ice Data Center.
There is absolutely nothing worse than getting into a black painted car with a black interior in the afternoon of a hot, sunny summer day. Just crack open the door and waves of heat strikes roll over you as the hot air escapes the vehicle. Black cars become hot because the sunlight striking the car is absorbed by the black paint. In contrast a silver or white car is cooler, because the sunlight striking the car is reflected away back towards the sky.
The same thing happens to the Earth’s air temperature. It’s really warm above dark objects that absorb sunlight and cooler above light objects that reflect that sunlight. And that is one of the many reasons why the ice covering the Arctic and Antartic regions is so vital, when sunlight strikes the ice, it is reflected back to space, cooling the Earth’s climate significantly.
This is why scientists are making such a fuss about the decrease in sea ice in the Artic Ocean. Sea ice acts as a reflective agent for the Earth moderating the climate. As the Earth warms in the next few years, the amount of ice will decrease as it melts, which in turn will further increase the temperature of the Earth as less sunlight is reflected and more is absorbed. Scientists refer to this as a “positive feedback” because an increase in one variable causes the system to respond by further increasing that variable.
This summer sea ice was found in greater abundance than was found in the summer of 2007. Summer is the point of the year that sea ice is at a minimum, and thus when the positive feedback is at its strongest. While having more sea ice this year is a good thing, it probably means very little in the long run, as the amount of ice found is still much less than what was observed for most of the 20th Century.
The annual summer retreat of the sea ice cloaking the Arctic Ocean appears to have ended with the ice not quite matching last year’s extraordinary recession, polar scientists said Tuesday.
Still, the scientists, at the National Snow and Ice Data Center in Boulder, Colo., said that the ice in the Arctic this summer was 33 percent below the average extent tracked since satellites started monitoring the region in 1979 and that the trend continued toward an ice-free Arctic Ocean within a few decades.
As people who’ve been through a winter or two will tell you, some years are colder than others and Arctic climate is no different. This year, was a bit colder than last year, but the long term trend is robust. Sea ice is declining rapidly during the summer, and soon there will likely be no summer ice to speak of.
Dr. Meier said that small variations from one year to the next were less significant than the long-term trajectory, which remained toward progressively more open water. “It’s hard to see the summer ice coming back in any substantial way,” he said.
Decreases in sea ice have impacts beyond that of just climate. While some of our nation’s greatest politicians, who are obviously experts in the field of climate science may not agree with recent finding regarding the findings showing that Polar Bears and other Arctic species may struggle in an environment suddenly devoid of ice, scientists note that this is also a major concern:
Federal biologists have said that this long-term ice retreat is the main reason they had concluded that polar bears, which hunt seals from the ice, deserved protection under the Endangered Species Act. The Bush administration listed the species in May as threatened with extinction.
Global warming from the buildup of human-generated greenhouse gases almost certainly contributes to the Arctic ice retreats, according to a host of Arctic specialists. But many say natural variations in Arctic winds and cloud cover probably had a role in shaping the particularly large ice losses in the past two summers.
It will be interesting to keep an eye on sea ice in the summer months during the next few years. Maybe we should put a pool together to pick the first year without any sea ice? It’d be like fantasy baseball, but fantasy climate. This could be a money winner…
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