Bloomberg: The shrinking of Arctic sea ice to its second-smallest size on record signals greater changes in the Earth’s climate as it opens previously frozen shipping routes. The polar ice, which melts from March to September each year and expands again as winter approaches, was only smaller in 2007, according to satellite data collected since 1979 and released today by the U.S. National Snow and Ice Data Center. The trend of reduced ice dates to even before 1979, according to measurements from …