President Joe Biden's administration on Monday approved an oil drilling project on Alaska's North Slope.
The Interior Department approved US energy company ConocoPhillips's request to drill for oil at three sites in the federally owned National Petroleum Reserve in Alaska's pristine western Arctic.
During the 2020 presidential race, Mr Biden had vowed not to approve any new leases for oil and gas projects on federal lands and his administration had been under intense pressure by environmental groups in recent days not to approve the so-called Willow Project.
Alaska lawmakers and other backers of the project had lobbied strongly for its approval, defending it as a source of several thousand jobs and a contributor to US energy independence, with production of 180,000 barrels of oil per day at its peak, or about 576 million barrels over 30 years.
Environmental groups expressed disappointment at the Interior Department move.
“We are too late in the climate crisis to approve massive oil and gas projects that directly undermine the new clean economy that the Biden administration committed to advancing,” said Earthjustice president Abigail Dillen.
“We know President Biden understands the existential threat of climate, but he is approving a project that derails his own climate goals.”
Ben Jealous, executive director of the Sierra Club, said: “The harmful effects of President Biden's decision cannot be overstated.
“Willow will be one of the largest oil and gas operations on federal public lands in the country, and the carbon pollution it will spew into the air will have devastating effects for our communities, wildlife and the climate.
“We will suffer the consequences of this for decades to come.”
The Donald Trump administration approved the Willow Project at the tail end of the former president's term, but it was blocked by a judge for further review.
The Bureau of Land Management, in an environmental impact analysis in February, approved three drilling sites, while striking down one and deferring consideration of another.
Mr Biden has described global warming as an existential threat and promoted the development of renewable energy sources.
Temperatures in Alaska have been rising faster than in other parts of the planet and environmental groups have warned that the oil extraction project would only make things worse.
The Willow Project will add more than 250 million metric tonnes of carbon emissions to the atmosphere over the next 30 years, the Sierra Club said, equivalent to the annual emissions of 66 coal plants.
Greenpeace has described it as a “carbon bomb”.
A petition on Change.org seeking to halt the project garnered more than three million signatures and a #StopWillow campaign on TikTok drew tens of millions of views.
Alaska's two Republican senators and the state's sole member of the House, Mary Peltola, a native Alaskan and a Democrat, met Mr Biden earlier this month to urge him to approve the project.
Ms Peltola, in an opinion piece published in The Hill, said Alaskans “aren't blind to the impacts of climate change” but the Willow Project can serve as a bridge, as the country transitions away from fossil fuels and towards renewable energy sources.
“At the same time, we can reduce America's dependence on foreign sources of oil — which makes us all safer in a world that has grown more unpredictable after Russia invaded Ukraine,” Ms Peltola said.
Mr Biden has pledged to cut greenhouse gas emissions in half by 2030 compared to 2005, with the goal of achieving a net-zero emissions economy by no later than 2050.