Reflecting on the Melt
As you've surely read or heard by now, Arctic sea ice extent reached record lows this month, shattering the previous record set in September 2005. According to the National Snow and Ice Data Center (NSIDC), the five-day mean ice extent for September 16, 2007, was lower by one million square miles (an area roughly equal to the size of Alaska and Texas combined) than the long-term average. The NSIDC is careful to stress that sea ice extent can vary greatly from one year to the next, but also states that the 2007 minimum is "a bold exclamation point on a trend of ice loss that has been ongoing for at least the past fifty years."NASA notes that the increased summer melt is mirrored by an equally alarming decrease in winter ice extent:
The maximum amount of sea ice in the Arctic winter has fallen by six percent over each of the last two winters, as compared to a loss of merely 1.5 percent per decade on average annually since the earliest satellite monitoring in 1979.The alarming sea ice retreat will not impact sea level (although melting of the Greenland ice sheet certainly will), but it will have many other serious repercussions. Among the most obvious and most frightening is the positive feedback loop that a melting Arctic is expected to create; i.e., as the reflective ice surface is replaced by an energy absorbing ocean surface, melting is liable to beget more melting.
The loss of sea ice is also problematic for many species -- and not just polar bears. As Joey Comiso, a research scientist at NASA's Goddard Space Flight Center, explains:
The seasonal ice regions in the Arctic are among the most biologically productive regions in the world. For example, sea ice provides melt-water in spring that floats because of low density. This melt-water layer is considered by biologists as the ideal layer for phytoplankton growth because it does not sink, and there is plenty of sunlight reaching it to enable photosynthesis. Plankton are at the bottom of the food web. If their concentration goes down, animals at all trophic levels would be deprived of a basic source of food.
4 Comments:
Ah, such wonderful news. When will people start listening?
I don't know. The press apparently isn't given the Antartic ice is at record high coverage. But its so much simpler to just react...
The Antarctic picture does appear to be more complex, but I'd call your attention to the stories here and here, that show that Antarctica is melting farther inland and at higher altitudes than in previous decades.
Unlike melting sea icea in the Arctic, melting on the Antarctic ice sheets has serious consequences for sea level.
Scientists had predicted that higher (but still sub-freezing) temperatures in the Antarctic would bring more snow over the south polar region and thus increase the ice mass on the White Continent. That doesn't appear to be the case, however.
Back in the spring of 2006, papers in Science and elsewhere concluded that Antarctica's total ice mass was shrinking significantly.
So, I think this idea that Antarctic ice is increasing is erroneous. But if you have other sources to contradict that, please provide them.
As long as we have news media that puts more emphasis on Britney Spears status and what is or has happened to her child custody matter than we do items of importance, what can you expect. First we had Angelina Jolee or whatever her name was and now this crap. What has happened to our news. I suppose if it isn't glamored up no one is interested in it.
I keep forgetting the short attention span the american public has their lack of concern for things of importantce.
Post a Comment
<< Compass Main