This summer, for the first time in recorded history, there may be no ice on the North Pole. In a dramatic symptom of climate change, the thick frozen layer at the pole is likely to melt away entirely, turning the top of the world from sea ice to sea water.

The polar ice has been thinning steadily over the years. Where there used to be thick ice, composed of layers formed over multiple years, nowadays the polar region is largely covered with single-year ice, a much thinner and more temporary layer that’s replaced every year. This less durable stuff is significantly more prone to melting away — which is exactly what it’s doing. In 2007, the melt came within 700 miles of the pole. According to polar scientists, the ocean will open up even further this year — probably, depending on weather, all the way to the pole. One of the useful features of a big patch of white ice is that it reflects sunlight and reduces the ambient temperature. Without that icy albedo, the Earth is likely to absorb more heat, creating a positive feedback loop and speeding up the global warming process.

If 2008 stands to be the first year that the pole can be reached by boat, that’s good news for oil-drillers, who’ve always had their access to the rich Arctic deposits blocked by ice. And it’s a boon for the sort of Arctic explorers who are prone to getting their ships stuck in the polar sea ice and having to eat their crew. But it’s a shocking and worrying milestone for the rest of us Earth-dwellers, who’ve always been able to count on solid ice due North.

[Via The Independent]