The Obama administration on Wednesday announced its latest move to combat global warming, this time trying to rein in heat-trapping methane gas that escapes from oil and gas fields.
The plan relies on voluntary steps and new rules to reduce leaks from oil and gas production by 40 percent to 45 percent over the next decade. In a way, the proposal is an effort to plug what many viewed as a hole in the overall global warming strategy.
Rules to clean up carbon dioxide from coal-fired power plants have helped shift electricity generation from coal to cleaner-burning natural gas. But without tackling the methane leaks, the climate benefits from the switch are diminished.
Emissions from oil and gas are projected to rise by more than 20 percent by 2025 without any controls. Five things to know about the White House's plans:
AWAITING THE RULES
The new plan is a broad outline of how the administration hopes to curb methane emissions from oil and gas operations.
The main rules are not yet proposed, so it's not fully clear how the 40 percent to 45 percent range of reductions from 2012 levels would be achieved.
The plan says the Environmental Protection Agency this summer will propose the first standards for methane from new or modified oil and gas sites. The Interior Department this spring will propose new standards on venting, flaring and leaks from national gas sites on federal land.
The Interstate Natural Gas Association of America said it 'reserves judgment on the plan until it sees more details.' David Arkush, managing director of Public Citizen's Climate Program, said stronger and faster curbs were needed.
'It's disappointing that the EPA issued a plan to regulate rather than proposing an actual rule,' he said.
WHAT ABOUT EXISTING WELLS?
For now, the plan excludes the hundreds of thousands of oil and gas wells already drilled - and the infrastructure that supports them.
About 30 percent of U.S. emissions of methane come from oil and gas sites; most of those emissions come from wells and infrastructure in place.
The proposal targets only new or modified sites. While the EPA could choose later to regulate existing oil and gas wells, administration officials have not said that's the idea.
New York Attorney General Eric T. Schneiderman, who threatened to sue the agency in 2012 for not regulating methane, said it was 'essential that EPA also act on its responsibility under the Clean Air Act to regulate methane emissions from existing sources.'
ENVIRONMENTAL EFFECTS OF LEAKS
The leaks threaten to undermine the environmental benefits of natural gas compared with coal.
Two studies released last year found that leaks from natural gas fields globally could make natural gas worse for the climate than coal over the next few decades.
The same research found that U.S. oil and gas fields emitted more than the industry does on average in the rest of the world.
Not addressing leaks in the U.S. means that one of the main parts of Obama's strategy to curb global warming - shifting electricity generation from coal to cleaner-burning natural gas - was potentially flawed.
Methane accounts for only 10 percent of U.S. greenhouse gas emissions, but it is 25 times more powerful at trapping heat than the chief greenhouse gas, carbon dioxide, over a century.
LEAKS ARE ON THE DECLINE
Methane leaks are declining even as the U.S. produces more oil and gas than ever.
U.S. oil production is at its highest level in nearly 30 years, and the country is now the world's largest producer of natural gas. Despite the current energy boom, methane emissions from oil and gas production have declined by 12 percent since 2011 and 16 percent since 1990, according to the EPA. The industry says that shows no more regulation is needed.
'Another layer of burdensome requirements could actually slow down industry progress to reduce methane emissions,' said the American Petroleum Institute's president, Jack Gerard.
NATURAL GAS BEST WAY TO ADDRESS GLOBAL WARMING?
Even if the administration meets its goal, natural gas might not be the best solution to address global warming.
An international study released in the journal Nature said using cheap natural gas for electricity could hinder the growth of even cleaner energy sources such as wind, solar and nuclear, and lead to a rise in emissions of heat-trapping pollution from electricity. But this research assumed that current policies would not change.