Climate Central: The skin of sea ice that covers the Arctic Ocean has reached its maximum extent for 2013, the National Snow and Ice Data Center announced Monday, and the annual melt season has begun. As of March 15, ice covered 5.84 million square miles of ocean, the sixth-lowest since satellite observations began in the 1970's, and 283,000 square miles lower than the 1979-2000 average. Reflecting the influence of global warming, the 10 lowest sea ice maximums have all occurred over the past 10 years.
Last summer's...