Associated Press: The Arctic is treading on thinner ice than ever before. Researchers say that as spring begins, more than 90 percent of the sea ice in the Arctic is only 1 or 2 years old. That makes it thinner and more vulnerable than at anytime in the past three decades, according to researchers with NASA and the National Snow and Ice Data Center in Colorado. “We’re not set up well for summertime,” ice data center scientist Walt Meier said Monday. “We’re in a very precarious situation.” Young …