Environment groups are coming together to protest against plans by the US government to open up a vast area of Arctic sea off Alaska for oil exploration, arguing it poses an unacceptable new threat to polar bears and walruses.

The Minerals and Management Service, MMS, said it would be seeking bids for petroleum licences in the Chukchi Sea on 6 February.

The 46,000-square-mile area, located between Alaska and the coast of the Russian Far East, supposedly holds 15 billion barrels of recoverable oil and a huge volume of natural gas.

It is also home to one of the two main populations of polar bears in US territory, as well as large herds of walrus. “The chances for the continued survival of this icon of the Arctic will be greatly diminished if its last remaining critical habitat is turned into a vast oil and gas field,” argues Margaret Williams from WWF.

“We’ve seen all these studies and reports concerning significant impacts to marine mammals from global warming,” added Betsey Beardsley, of the Alaska Wilderness League. “If you couple that with increased oil and gas development, there’s no telling what impact that would have on marine life.”