National Geographic: Data released this week by a team of explorers who trekked through the Arctic for three months this spring shows the North Pole will be an open sea during the summer months within 20 years. The Catlin Arctic Survey team, led by explorer Pen Hadow, measured the thickness of the ice as they sledged and hiked through the northern part of the Beaufort Sea in the geographic north Pole. Their findings show that most of the ice in the region is first-year ice that is only around six …