WASHINGTON (AP) -- The Arctic is treading on thinner ice than ever before.

Researchers say that as spring approaches, more than 90 percent of the sea ice in the Arctic is only one or two years old. That makes it thinner and more vulnerable than ever before, according to researchers with NASA and the National Snow and Ice Data Center in Colorado. That’s the type of ice that is more likely to melt in the summer.

Sea ice is important because it reflects sunlight away from Earth. The more it melts, the more heat is absorbed by the ocean, heating up the planet even more. That warming also can change weather patterns worldwide.

Posted 4/6/2009