A sailing expedition to the North Pole to raise awareness of global warming has been forced to turn back, 590 nautical miles short of its destination, after the yachts found their passage blocked by large quantities of an unexpected frozen white substance. According to Arctic Mission’s website: A meeting of the four skippers was held led by Erik de Jong, with Pen Hadow present, and it was agreed further northward progress would increase considerably the risks to the expedition, with very limited scientific reward. The decision to head south, back to an area of less concentrated sea ice in the...