New Scientist: It might be one of the coldest regions on the planet but the Arctic is warming twice as fast as the rest of the globe – and now we know the reasons why. Two new studies show that the greenhouse effect is stronger above the North Pole, and that the waters of the Arctic Ocean are acting like a radiator to heat the region’s atmosphere. The warming of the Arctic has been explained before as being due to a positive feedback loop: as the ice cap melts and disappears, more of the dark ocean …