WASHINGTON — 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 sea ice in the Arctic often melts in the spring and summer. If it survives for two years, then it becomes the type of thick sea ice that is key. But the past two years were warm, and there's more young, thin ice at the top of the world.
In normal winters, thick sea ice — often about 10 feet thick or more — extends from the northern boundaries of Greenland and Canada almost to Russia. This year, the thick ice cap barely penetrates the bull's-eye of the Arctic Circle.
The amount of thick sea ice hit a record wintertime low of just 378,000 square miles this year, down 43 percent from last year, Meier said. The amount of older sea ice that was lost is larger than the state of Texas.
"That thick ice really traps ocean heat; it keeps the planet in its current state of balance," said Waleed Abdalati, director of the Center for the Study of Earth from Space at the University of Colorado and NASA's former chief ice scientist. "When we start to diminish that, the state of balance is likely to change, tip one way or another."
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, said NASA polar regions program manager Tom Wagner. That warming also can change weather patterns worldwide and it alters the ecosystems for animals such as polar bears.