• Methane emissions are a state problem,

Methane is 24 times more potent than carbon dioxide at trapping heat in the atmosphere over a 100-year period — a range scientists believe is crucial to contain global temperature rises.

When President Donald Trump announced he wants no part of the Paris climate agreement, binding nearly all of the world’s nations to decreasing global warming emissions, Pennsylvania’s role in taking on methane — a powerful greenhouse gas that is the main component of the state's growing oil and gas industry — came into sharper focus.

“Gov. Wolf knows that in the absence of federal leadership on this issue, Pennsylvania must ensure reasonable protections from methane and continues to work toward that goal,” said J.J. Abbott, a spokesman for Pennsylvania Gov. Tom Wolf.

Methane is 24 times more potent than carbon dioxide at trapping heat in the atmosphere over a 100-year period, and 84 times more powerful over 20 years, which is the range that scientists believe is most crucial to contain global temperature rises.

Pennsylvania's relationship with methane is complicated.

It is the reason that oil and gas companies, including international giants like Chevron and Shell, have made large investments in the state.

The draw of the Marcellus Shale ushered in a boom at the turn of the decade and while it was followed by a now thawing downturn, the industry is here to stay for the foreseable future. There are more than 10,000 shale wells in Pennsylvania, and several hundred compressor stations, treatment plants and transmission stations. Not to mention the hundreds of miles of new pipelines being put in the ground.

All of that infrastructure carries methane and all of it leaks to a certain extent.

How much is difficult to know. The state Department of Environmental Protection requires oil and gas companies to submit annual inventories of emissions, but those aren't based on annual measurements. Instead, they're calculated using a formula that plugs in variables including the number of components on a piece of equipment and how much gas is traveling through it.

Direct measurements, done by researchers and environmental groups, tend to show that while in most places methane emissions are low, there are pockets of high emissions — large leaks.

A new state permit for oil and gas wells that would, for the first time, put restrictions on emissions, is currently wrapping up its public comment period.

And while Mr. Wolf promised to also address methane emissions from existing infrastructure — like those 10,000 wells already in the ground — he has yet to propose a mechanism for doing so.

Meanwhile, efforts are underway in Harrisburg to cut the legs from under such measures. A bill has been introduced that wants to ensure Pennsylvania environmental standards are not more stringent than federal rules. Another essentially seeks a legislative veto for any regulation that would cost more than $1 million to implement.

“If Pennsylvania defers to the federal government for protections, well, they won’t be there,” Andrew Williams, director of regulatory and legislative affairs at New York-based Environmental Defense Fund, wrote on May 25.

“Tying Pennsylvania policies to whatever is happening in D.C. hardly serves the interest of Pennsylvania citizens and communities — instead, it’s a bouquet to industry,” he wrote.

Even before Mr. Trump officially unveiled his position on the Paris climate agreement, his Environmental Protection Agency had already gotten to work on stalling and reversing regulations aimed at curbing methane emissions.

Under the leadership of Scott Pruitt, who as Oklahoma's attorney general sued the EPA over many of the regulations he's now reversing, the federal agency has sent a signal to the oil and gas industry that methane emissions are no longer a concern.

In March, it told oil and gas companies that they needn’t comply with the agency’s prior request to submit an inventory of their emissions.

A few weeks ago, the EPA put on hold efforts to mitigate methane seeping out of landfills, the third largest contributor of methane behind agriculture and the natural gas industry in the U.S.

And just on Wednesday, the agency put on hold a measure that was supposed to tighten leaks from new oil and gas wells after industry groups asked the EPA to reconsider the rule which has already gone into effect.