We recently talked about Greenland melting in 2007. Along similar lines, the New York Times posted an article yesterday titled Arctic Melt Unnerves the Experts. It's well worth a read if you're into grim factoids about the environment, this time talking about the Arctic polar ice cap. There is also a neat time graphic showing the melting patterns in the past few years. In short: as far as anyone can remember, the Arctic's ice melted the most and is scaring the scientists who can't predict it reliably and who need to figure out the full implications.

The implications of losing this much ice are staggering. A few thoughts:

• The Arctic ice sheet may not recover fully if it loses too much ice in a year.
• Polar ice reflects sunlight and so helps the Earth stay cooler. What happens when it's lost is complex. An excellent introduction to the topic is on NASA's Earth Observatory website.
• A receding ice cap opens up shipping lines. We can already do that during the summer, but the routes may become open for longer and starting earlier in the year in the future.
• The receding ice sheet makes it easier to hunt for resources. Will we be seeing oil rigs at the North Pole in a couple of decades? Do we want to?
• What about wildlife that depends on an icy environment?

As ever, a complex topic with bad news sprinkled in for fun.