President Joe Biden's administration on Wednesday announced it was banning new oil and gas drilling over a vast region of Alaska that is significant to indigenous communities and home to many animal species.
The move follows a decision by the US government earlier in the year to approve a ConocoPhillips project in the same area.
The new prohibition will cover 4.3 million hectares, or 40 per cent, of the National Petroleum Reserve in Alaska, or NPR-A, an ecologically important region for grizzly and polar bears, caribou and hundreds of thousands of migratory birds.
“Alaska is home to many of America's most breathtaking natural wonders and culturally significant areas,” Mr Biden said in a statement.
“As the climate crisis warms the Arctic more than twice as fast as the rest of the world, we have a responsibility to protect this treasured region for all ages.”
The US Interior Department said it is also cancelling seven remaining oil and gas leases that were authorised under former president Donald Trump in the Arctic National Wildlife Refuge, which lies to the east of the NPR-A, also on Alaska's North Slope.
While Mr Biden's statement trumpeted the latest actions, his administration has come under heavy fire from environmentalists for approving the massive ConocoPhillips oil project in the NPR-A.
The so-called Willow project, estimated to cost between $8 billion to $10 billion, was initially authorised under Mr Trump and later backed by Mr Biden, triggering widespread national protests led by youth activists.
Observers have said the new announcements to protect more of the Arctic may be in part aimed at defraying some of the criticism aimed at Willow.
The new plan would also limit, but not outright ban, drilling in an additional 970,000 hectares of the NPR-A, and support subsistence activities for Alaska's native communities.
It would also ban drilling in about 1.1 million hectares of the Beaufort Sea, “ensuring the entire United States Arctic Ocean is off limits to new oil and gas leasing”.
The NPR-A is the largest tract of public land in the US and was created by former president Warren Harding in 1923. In 1976, Congress directed that extraction of fossil fuels there must be balanced against the need to protect the environment.
Mr Biden pledged during his presidential campaign to halt all new leasing on federal land and water – a promise he failed to keep.
Some observers say his decisions were limited by unfavourable court decisions in the face of challenges led by Republican states, and credit the administration for limiting the scope of new developments.
On the other hand, his administration also oversaw the passage of the Inflation Reduction Act, which committed nearly $400 billion to fighting climate change.
A study published in the journal Science in July said the act would lead to economywide greenhouse gas emissions reductions from 43 to 48 per cent below 2005 levels by 2035.
That however would still fall short of the US target to cut 50 per cent of emissions by 2030.
