2007 held the dubious distinction as the year where Arctic sea ice retreated to its geographically smallest extent since record-keeping began in 1979. Just 1.54 million square miles of sea ice remained at the pole at the end of last summer. 2008, in one respect, just barely missed the grade: 1.79 million square miles of ice remained before the autumn cold began to reconstitute the icepack.

Scientists at the National Snow and Ice Data Center here in Boulder, Colorado, however, are heartened not at all by this news: the icecap this summer started off larger yet thinner than 2007's, and a larger total volume of ice melted this year compared to last year. Both the Northern Sea Route along the northern coast of Siberia and the Northwest Passage through Canadian waters were open this summer, and even remained open simultaneously for a short period.

In many respects, this summer's decline was more worrisome than last year's, because this year's ice was markedly thinner and weaker than 2007's. The gradual decline in sea ice extent since 1979 is attributed to climate change.

If there's any good news, it's that Arctic winds and weather also plays a role -- and these contributed to the scarily small icecap this summer. It's generally expected that next year will see significant ice cover gains, resuming a decline that is gradual, not precipitous as the past two years have been. That ice, however, is expected to be thinner and more prone to melting. If the trend established by the past few years held, we'd expect to see ice-free northern summers by 2013; this is unlikely, though, as the trend is skewed sharply downward by 2007 and 2008. However, it's not unimaginable that, sometime in the next two to three decades, the North Pole will be uncovered for the first time in known history.