President Joe Biden's administration has announced it is banning new oil and gas drilling over a vast region of Alaska that is significant for Indigenous communities and home to iconic animal species.
The decision on Wednesday follows a controversial move by the US government earlier in the year to greenlight a ConocoPhillips project in the same area.
The new prohibition covers 10.6 million acres, or 40 percent, of the National Petroleum Reserve in Alaska [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," 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.
'War on Alaska'
Alaska political leaders — including some Democrats — have long pushed to allow oil and gas drilling in the refuge in part because of its economic impact on Indigenous communities in an area with few other jobs.
Many of those same voices pressed Biden to approve the Willow project for the same reason.
The state's two Republican senators blasted the White House, saying Biden was undermining US energy security.
"These decisions are illegal, reckless [and] defy all common sense," said Senator Lisa Murkowski.
Democrat Mary Peltola, a member of the House of Representatives, also said she was "deeply frustrated" at what she described as a failure by the Biden government to listen to local desires.
Alaska Republican US Senator Dan Sullivan denounced Biden's actions as the latest volley in what he called a "war on Alaska."
Though 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 $8-10 billion, was initially authorised under Trump and later backed by 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 2.4 million acres of the NPR-A, and support subsistence activities for Alaska Native communities.
It would also ban drilling in approximately 2.8 million acres of the Beaufort Sea, "ensuring the entire United States Arctic Ocean is off limits to new oil and gas leasing."
America’s largest tract of public land
The NPR-A is the largest tract of public land in the United States and was created by former president Warren Harding in 1923.
In 1976, Congress directed that the extraction of fossil fuels there must be balanced against the need to protect the environment.
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 [IRA], which committed nearly $400 billion to fighting the climate crisis.