“At some point, we have to leave oil and gas and coal in the ground. And for me, that some point is now — particularly in a vulnerable ecosystem like the Arctic,” said Rob Jackson, a climate scientist at Stanford University.

Interior Secretary Deb Haaland, in announcing Willow’s approval, stressed that the number of drill pads was reduced by 40% from ConocoPhillips’ original proposal, which she said would benefit people and wildlife. But the company still is expected to get most of the oil it wanted, resulting in only an 8% reduction in greenhouse gas emissions, according to government estimates.

For Alaska, the project promises an economic boost after oil production dropped sharply since the late 1980s. Leaders from both parties in the state united behind it. Oil has long been the state’s economic lifeblood, with revenues helping remote communities and villages on Alaska’s petroleum-rich North Slope.

But the state also has felt the impacts of climate change: coastal erosion is threatening Indigenous villages, unusual wildfires are popping up, sea ice is thinning and permafrost promises to release carbon as it melts.

Attorneys representing environmentalists and an Alaska Native group filed a lawsuit Tuesday asking a federal judge to block Willow’s approval. The Sovereign Iñupiat for a Living Arctic, Sierra Club and other groups said Interior officials ignored the fact that every ton of greenhouse gasses emitted by the project would contribute to sea ice melt, which endangers polar bears and Alaskan villages.

The International Energy Agency has said new drilling investments must be halted if nations, including the U.S., hope to reach their 2050 goal of net-zero emissions, meaning only as much planet-warming gas is released into the atmosphere as can be absorbed.

The energy sector accounts for 90% of carbon dioxide emissions worldwide and three-quarters of the total human-made greenhouse gases.

Yet global demand for crude is expected to continue rising, according to industry analysts and the U.S. Energy Information Administration.

Instead of targeting domestic supplies of those fuels — including projects like Willow — energy expert Jim Krane said policymakers should focus on reducing demand.

“If you target supply in the U.S. without any kind of measures to bring demand down, refiners are just going to pull their oil from overseas,” said Krane, of Rice University’s Baker Institute for Public Policy.

Electric vehicles offer a potential substitute for gasoline-powered cars and trucks, but so far they’ve barely dented fossil fuel demand. By 2030, EV is expected to displace 2.7 million barrels of oil a day, according to Enverus Intelligence Research, a data analysis firm focused on the energy industry.

That’s less than 3% of global oil consumption, which in 2030 is anticipated to be about the same as current levels — roughly 100 million barrels a day, said Al Salazar, senior vice president of the research company.

“Demand does not go to zero in a blink-of-the-eye,” Salazar said. “It takes time to turn over the entire light duty vehicle fleet.”

The Willow project is in the National Petroleum Reserve-Alaska, where Republican U.S. senators have noted drilling should be expected.

Greenhouse gases from Willow would equal emissions from about 1.7 million cars, or just over 0.1% of the U.S. total. Interior Department officials for years have cited such relatively small percentages as justification for approvals of coal mines and oil and gas leases.

Jackson said that perspective can’t continue if the worst effects of climate change are to be avoided. The planet is “as far from zero emissions as we’ve ever been” despite the emphasis on renewable energy.

“It’s the same as thinking, well, every new car we put on the road or coal plant we build doesn’t matter because there are millions of other cars and thousands of other coal plants around the world operating,” he said.

Prior to the Willow decision, the administration already had softened its opposition to oil and gas — a departure from the early days of Biden’s presidency. During negotiations over last year’s climate bill the administration agreed to tens of millions of acres of new leasing to get the support of Democratic holdout U.S. Sen. Joe Manchin, of West Virginia.

Provisions in the measure link oil and gas leasing to renewable energy development. Consequently, the administration will offer for sale more than 73 million acres of oil and gas leases for sale March 29 in the Gulf of Mexico. Over several months beginning in May, it also plans to auction some 350,000 acres of onshore oil and gas leases in Wyoming, New Mexico, Montana, Nevada and other states.

Environmentalists say the Gulf sale alone could yield more than 1 billion barrels of oil over 50 years.

“This administration has pledged to oversee a historic transition to clean energy, but actions speak louder than words,” said Earthjustice attorney George Torgun, who represents environmental groups trying to stop further lease sales.

Brown reported from Billings, Montana.