"There are significant, highly cost-effective opportunities for reducing methane emissions from this sector," said Dan Utech, Obama's climate and energy adviser. "We're confident we can do this in a cost-effective way."

How much will the regulations cost the energy industry? The White House said it won't have specific estimates until later.

"Grassroots opposition to fracking has helped make this issue a national priority, and it deserves the credit for pushing the White House to take action," she said in an email. "While the proposed regulations acknowledge the major climate threat posed by fracking, they give a free pass to many existing sources of methane pollution, like leaky transmission and distribution infrastructure."

Linda Capato, of environmental group 350.org, told Al Jazeera that the new proposal is a "small step forward" because it neglects to target existing sources of methane pollution.

The White House set a new target for the U.S. to cut methane emissions by 40 percent to 45 percent by 2025, compared to 2012 levels. To meet that goal, the Environmental Protection Agency will issue a proposal affecting oil and gas production, while the Department of the Interior will also update its standards for drilling to reduce leakage from wells on public lands.

Relying once again on the Clean Air Act, the rules join a host of others that President Barack Obama has ordered in an effort to slow global warming despite opposition to new laws in Congress that has only hardened since the midterm elections. Although just a sliver of U.S. greenhouse gas emissions, methane is far more powerful than carbon dioxide at trapping heat in the atmosphere.

The Obama administration laid out designs Wednesday to issue the first regulations to cut down on methane emissions from new natural gas wells, aiming to curb the discharge of a potent greenhouse gas by roughly half.

Proposal falls short

Methane, which leaks during production of natural gas, has grown as a concern for environmentalists amid the ongoing boom in drilling for oil and natural gas in the U.S. Yet these rules will target new or modified natural gas wells, meaning thousands of existing wells won't have to comply. The Obama administration left open the possibility it could regulate methane from existing wells in the future while asking the energy industry to take voluntarily steps to curb emissions in the meantime.

Though long in the works, the methane plans come at a particularly sensitive moment for Obama's environmental agenda. Republicans, incensed that Obama has made use of executive action to sidestep Congress on climate and other issues, have made rolling back those actions one of their first orders of business now that they control both chambers of Congress.

Obama's intention to eventually force industry to cut methane emissions has long been part of his broader strategy on climate change, and Wednesday's announcement may prove to be incremental.

Last year, the White House said the EPA would study how methane is released during drilling and determine whether it needed new regulations. That the administration has now decided it does need more regulations will surprise few. But the key details — how the regulations will affect industry's bottom line and how deeply they'll reduce greenhouse gases — won't come until the government formally proposes the rule. That won't come until later this year, with plans to finalize it in 2016 — the last year of Obama's presidency.

Officials couldn't say how far the rules will go toward meeting Obama's goal to cut overall greenhouse gas emissions up to 28 percent by 2025, other than that the contribution would be "significant." But environmentalists argue that cutting methane is key to curbing climate change, and some scientists have said that without methane controls, the country's shift from coal to natural gas will have less of an environmental benefit. "This is a landmark moment," said Fred Krupp of the Environmental Defense Fund.

But 350.org's Capato takes a different view, advising the White House to follow the lead of New York, which recently banned fracking.

"Even if the regulations were more sweeping, they still wouldn't justify the ongoing expansion of fracking, a risky practice that endangers our communities, water and climate," she said. "Governors, and other public officials, should follow the example set by New York and ban this dangerous practice once and for all."

She added, "The only way to seriously address climate change is to leave fossil fuels in the ground — when you're in a hole, the first rule is: stop digging."

Meanwhile the oil and gas industry has insisted such rules aren't necessary because the industry is already working to reduce methane leakage. After all, methane is natural gas, so the less that leaks during production, the more of it that companies have left to sell.

"We're doing a good job," said Howard Feldman, the regulatory director at the American Petroleum Institute. He noted that existing pollution rules on smog-forming pollutants have had the added benefit of cutting methane. "We don't think it's necessary to go after methane in any way, shape or form."

Al Jazeera and The Associated Press