The Biden administration approved a major and controversial oil drilling plan in Alaska, known as Willow, just one day after unveiling protections for more than 16 million acres of land and water in the region.

The $8 billion plan, led by Alaska’s largest crude oil producer, would produce about 600 million barrels of oil over 30 years and generate around 278 million metric tons of carbon emissions, according to estimates from the U.S. Department of the Interior.

Under the plan, ConocoPhillips will be allowed to develop three well pads within the National Petroleum Reserve-Alaska, a 23 million-acre area that is the largest expanse of public land in the U.S.

The approval of Willow is one of the president’s most consequential climate decisions. Environmental groups have long condemned the plan, arguing it undermines the administration’s pledge to combat climate change and reduce greenhouse gas emissions. The project’s emissions would be about equivalent to what 66 new coal-fired power plants produce in a year.

Proponents of Willow, including the state’s congressional delegation and some Alaska Native tribal governments and residents of Alaska’s North Slope, have said the plan would create about 2,500 jobs, deliver up to $17 billion in revenue for the federal government and boost U.S. domestic energy security.

Prior to the president’s decision, the Interior Department’s Bureau of Land Management released an environmental analysis last month that proposed lowering the number of drilling sites from five to three under the project. The Interior said it had “substantial concerns” about Willow, including its direct and indirect emissions and its impact on local wildlife.

In addition to lowering the number of drill sites, the Interior said Monday that ConocoPhillips would relinquish rights to about 68,000 acres of existing leases in the National Petroleum Reserve-Alaska to the government, a decision it said would create a buffer from exploration and development in the region outside the project.

Ryan Lance, ConocoPhillips chairman and chief executive officer, in a statement, said the approval “was the right decision for Alaska and our nation.”

“Willow fits within the Biden administration’s priorities on environmental and social justice, facilitating the energy transition and enhancing our energy security, all while creating good union jobs and providing benefits to Alaska Native communities,” Lance said.

In an apparent effort to offset criticism about the project’s climate impact, the administration on Sunday declared the Arctic Ocean off limits to oil and gas leasing and said it will also impose regulations to protect nearly 13 million acres in the National Petroleum Reserve-Alaska.

While climate groups praised the administration’s plans to protect the Arctic, they strongly condemned Willow and vowed to challenge the project in court. 

“It’s insulting that Biden thinks this will change our minds about the Willow project,” said Kristen Monsell, a senior attorney at the Center for Biological Diversity. “Protecting one area of the Arctic so you can destroy another doesn’t make sense, and it won’t help the people and wildlife who will be upended by the Willow project.”

Christy Goldfuss, chief policy impact officer at the Natural Resources Defense Council, called the decision to approve Willow a “grievous mistake” and said the group will continue its fight to stop the project.

“It green-lights a carbon bomb, sets back the climate fight and emboldens an industry hell-bent on destroying the planet,” Goldfuss said. “It’s wrong on climate and wrong for the country.”