The National Oceanic and Atmospheric Administration in December denied a listing under the Endangered Species Act for the seals, found off the coasts of Alaska and Russia.
The Center for Biological Diversity and Greenpeace sued in U.S. District Court, claiming the agency ignored the best science available on global warming. Shaye Wolf, a Center for Biological Diversity biologist, said her group had hoped NOAA officials would change its conclusions with a change in presidents.
"We've seen no change here," she said. "The Obama administration is continuing the flawed and head-in-the-sand policies of the Bush years."
NOAA spokeswoman Connie Barclay in Washington, D.C., had no immediate comment on the lawsuit.
Ribbon seals are found in the Bering and Chukchi seas off Alaska and in the Sea of Okhotsk off Russia. Ribbon seals are distinguished by the patterns of their fur that gives them the coloration of a panda bear: white bands or ribbons that encircle the head, base of the trunk and two front flippers over a dark coat.
Federal biologists estimate the population at about 200,000 globally with a Bering Sea population of 100,000 or more. During summer and fall, ribbon seals live entirely in the water, foraging on fish, squid and crustaceans.
From March through June, the seals rely on loose pack ice in the Bering and Okhotsk seas for reproduction and molting, and as a platform for foraging.
Ribbon seals give birth and nurse pups, which can't swim, exclusively on sea ice. Pups can survive submersion in icy water only after they've formed a protective blubber layer.
NOAA officials in December said climate models project annual ice will continue to form for the seals each winter during the critical birthing and molting period.
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