Green Options

August saw the fastest retreat of arctic sea ice on record, according to new NASA data. During that month, sea ice melted at a rate of 32,700 square miles per day, compared with 24,400 square miles per day in 2007. The rate of decline is even more dramatic when compared with the 30-year average rate of decline, 19,700 miles per day.

The accelerated seasonal retreat of sea ice surprised NASA scientists, who expected a more moderate retreat on the tail of a la Niña year. Moreover, the data show that one cold year, when sea ice levels are able return to normal, is not enough to counter the long-term melting of the arctic.

Sarah Palin has said many times that the polar bear habitat is safe, and there’s no need to classify them as a “threatened” species.  Yet today comes word that as the Arctic sea ice melts, polar bears are finding less and less food sources and are beginning to cannibalize one another.

According to the National Snow and Ice Data Center (NSIDC),

Following a record rate of ice loss through the month of August, Arctic sea ice extent already stands as the second-lowest on record, further reinforcing conclusions that the Arctic sea ice cover is in a long-term state of decline. With approximately two weeks left in the melt season, the possibility of setting a new record annual minimum in September remains open.

A record was set for Arctic sea ice melt in 2007.  Much was made of the sea ice “recovery” over the ensuing winter of 2007/2008.  However, while the Arctic sea ice returned to an extent similar to that of the winter prior to the record melt, much of the new ice was very thin.  Thus even though 2008 has been a cooler year than 2007 (partially due to a strong La Nina cycle), the new, thinner ice has proven to be more susceptible to melting, as the graphic following the jump illustrates.

This post is by Lisa Moore, Ph.D., a scientist in the Climate and Air program at Environmental Defense.

All year long we’ve been monitoring developments in climate science, and posting about the important new developments. I thought now would be a good time to look back over 2007 and summarize what we’ve learned.

Here are ten noteworthy science stories we covered in 2007:

1. The Sun is (really, really) not responsible for global warming. This paper wasn’t breaking news, just an extremely thorough review of the science showing why the sun can’t be blamed for global warming. The folks over at RealClimate said it best: “That’s a coffin with so many nails in it already that the hard part is finding a place to hammer in a new one.”

2. American Southwest climate is becoming drier. Global warming has caused a long-term shift in rain patterns. An author of the study said, “You can’t call it a drought anymore, because it’s going over to a drier climate. No one says the Sahara is in drought.”