Biden vowed to ban new drilling on public lands. It won't be easy.

Transforming that promise into reality, however, will be tough.

The incoming administration will face several legal and political hurdles if it seeks to halt new oil and gas permits on federal land and waters, given existing laws and the enormous sums that drilling royalties generate for the federal and state governments - including Democratic-leaning states such as New Mexico and Colorado. But failure to do so is sure to become a flash point with environmental and youth activists within the Democratic Party, who helped elect him and have made climate a priority.

Meanwhile, the Trump administration, in a bid to help its allies in the oil and gas business before it leaves office, has embarked on an 11th-hour leasing spree to help those companies lock in rights to drill. It offered up 79 million acres of leases in the Gulf of Mexico on Wednesday, selling nearly 518,000 acres. And it is rushing to auction off rights to drill in the Arctic National Wildlife Refuge by Jan. 20, Inauguration Day.

In a recent interview, Interior Secretary David Bernhardt said that Biden would not be able to halt new drilling on public lands and waters until his first term ends. "If their intention is to end all leasing and permitting, they will find that that's rife with conflicts, opposed by Democratic governors, and not perpetually legally sustainable."

But Michael Brune, head of the Sierra Club, one of the nation's oldest and most influential environmental groups, said his members expect nothing less than a ban from the candidate they helped elect.

"The Biden campaign made a clear and unequivocal campaign promise to end fossil fuel leasing on public land." Brune said. "That's a big reason why we had Sierra Club members write more than a million letters to undecided voters, make more than 5 million phone calls to undecided voters and send 20 million text messages."

There is little question that energy development on public lands and waters represents a significant share of America's global warming pollution. The fossil fuels that are extracted there and eventually burned to run cars, heat homes, operate factories and generate electricity account for nearly a quarter of U.S. carbon dioxide emissions, according to a 2018 U.S. Geological Survey study.

Still, lawmakers from both parties have welcomed drilling as a source of jobs and revenue for decades. President Barack Obama worked to curtail U.S. coal production on public land, but he praised natural gas production as an important bridge to clean energy. The Trump administration has moved aggressively to expand oil and gas drilling across the country, scaling back protected areas, offering more leases and accelerating federal approval for pipelines and other drilling-related projects.

Fossil fuel gas activity on federal and tribal land and offshore last year generated $11.7 billion in tax revenue, according to the Interior Department's Office of Natural Resources Revenue. Of that total, the U.S. Treasury kept $4.9 billion, more than $2.4 billion went to state and local governments and the rest funded tribes, restoration, conservation and other projects.

But as climate projections have become dire, Democrats have embraced a "keep it in the ground" strategy aimed at ending this activity altogether without the help of a sharply divided Congress. According to a Washington Post survey, every 2020 Democratic presidential candidate pledged to ban fossil fuel leasing with the exception of Montana Gov. Steve Bullock and Sen. Michael Bennet of Colorado, both of whom hail from energy-producing states.

Biden repeatedly brought up the issue on the campaign trail, saying that he would shift the nation away from fossil fuels while allowing fracking to continue on private land in places like Pennsylvania, which happened to be a swing state pivotal to his victory.

At a town hall in New Hampshire in February, he said he opposed drilling in the Arctic National Wildlife Refuge, given the impacts of climate change on Alaska, before adding, "And by the way, no more drilling on federal lands, period. Period, period, period." The crowd clapped enthusiastically.

Frank Macchiarola, the American Petroleum Institute's senior vice president for policy, economics and regulatory affairs, said in an interview that his group is well aware of Biden's pledge. "But we also recognize that that was a campaign proposal, and campaigning is often different from governing," he said.

"Our first order of business is to tell the story of the value of oil and gas production in the United States," Macchiarola said. He added that if Biden sought to impose a leasing ban, "we think there are a significant number of impediments to that, and we would challenge it vigorously." 

Legal experts from across the political spectrum said it will be easier to stop issuing new leases than to halt drilling permits linked to existing leases. Two primary laws govern leasing - the Mineral Leasing Act (MLA) and the Outer Continental Shelf Lands Act (OSCLA) - and both call for auctions at regular intervals. But the Obama administration suspended leasing both onshore and off at times, and the president has the right to remove offshore areas from leasing altogether.

It is much harder to deny a company the right to drill on a tract that is already leased. And it can take decades to cancel leases outright: Lawyers have been fighting for nearly 40 years over whether the U.S. government has the right to cancel oil leases that the Ronald Reagan administration awarded on land sacred to Montana's Blackfeet Nation.

The Trump administration has offered more than 100 million acres in onshore and offshore leases since taking office. More than 4 million acres have been sold in the Lower 48, and another 1 million on Alaska's North Slope.

"They're trying to lock in as many leases and as much climate pollution as they can before the Biden administration takes control," said Taylor McKinnon, a public lands campaigner for the Center for Biological Diversity, an advocacy group.

Some experts have begun to outline how the Biden administration could achieve "net-zero emissions" even if it continued to allow some oil and gas drilling.

Nada Culver, senior policy counsel at the National Audubon Society, recently co-authored a law review article that noted that Interior's Bureau of Land Management is required by law to protect "atmospheric values," and the agency could use that to impose new requirements on leases and permits.

Alex Daue, assistant director for energy and climate at The Wilderness Society Action Fund, said these requirements could include plugging up abandoned wells that are leaking greenhouse gases and financing restoration projects that could absorb carbon from the atmosphere and store it. "Public lands represent one of the Biden administration's best opportunities to tackle climate change," he said.

When it comes to curbing new leasing, New Mexico may pose the biggest challenge for the new administration. The Democratic-leaning state accounts for 57% of oil production on federal land and nearly a third of onshore gas extraction, according to a recent industry analysis, which projected New Mexico could lose $1 billion a year in federal revenue if all drilling activity ceased. Pumpjacks bobbing across the desert landscape funnel money to local governments and school districts through royalty payments and other drilling fees, even as politicians cite heat waves and prolonged drought as reasons to tackle climate change.

Democratic Gov. Michelle Lujan Grisham, a Biden ally, said this summer she would ask for an exemption from any leasing ban. Three New Mexico Democrats - Rep. Deb Haaland and Sens. Tom Udall and Martin Heinrich - are all in the running to be Biden's interior secretary, and they have differing views on whether to prohibit new drilling on public lands and waters.

Both Udall and Heinrich have expressed reservations about a total ban. In a recent interview, Udall called for setting a goal of "carbon-neutral" public lands, where the emissions from fossil fuel extraction could be offset by reforestation and other activities that remove carbon from the atmosphere. "That's where we should be headed," he said.

"Go into the departments that have the expertise and have the scientists and tell them this is your goal," Udall added. "How do we get there? What do we need to do? And then you can reapproach this in a concrete way and get it done."

But Haaland, who would be the first Native American to run the department that oversees federal and tribal lands, is more open to a straightforward ban. In September, she told reporters, "We don't need drilling everywhere."

Methane, a greenhouse gas that can be more than 80 times more potent than carbon dioxide, frequently escapes from oil patches in New Mexico and elsewhere. Haaland was referring to methane leaks when she added: "If I had my way, it'd be great to stop all gas and oil leasing on federal and public lands, because those lands belong to all of us; they don't just belong to one sector."

Regardless of who Biden selects to chart the nation's policies on fossil fuels, the intraparty fissures are already on display. The Biden team faced swift reprisal from environmental activists this week after naming Rep. Cedric Richmond, D-La., his campaign co-chair, as a senior White House adviser.

The oil and gas industry has viewed Richmond as one its chief advocates within Biden's inner circle.

Mike Sommers, head of the American Petroleum Institute, said before the election that the Biden campaign had been "pretty closed off to outside organizations" but that Richmond had "helped communicate messages" from the petroleum industry.

But Varshini Prakash, head of the youth-led Sunrise Movement that campaigned for Biden, said in a statement that hiring the Gulf Coast congressman who has raised money from oil and gas interests for a White House job "feels like a betrayal."

"Biden assured our movement he understands the urgency of this crisis; now, it's time for him to act like it."