When all the other fossil fuels are lined up in the room, natural gas wants you to think of it as the good guy.

So when America's Natural Gas Alliance CEO Marty Durbin, in an interview with the Washington Examiner, conceded humans play a role in contributing to climate change, it wasn't a tectonic shift. But it was seen as a change by a leader of an industry that is walking a fine line on the nexus of fossil fuels and climate change.

"I think you've got both natural and man-made causes of. So yeah, I think man-made activity does contribute to that," Durbin said.

Durbin has often touted the benefits that natural gas brings to reducing carbon emissions compared with coal, though without direct mention of humanity's impact on climate change. So some environmental groups were left wondering if Durbin had undergone a conversion or merely sensed an opportunity for his industry to better align itself with the Obama administration.

"His current job is to promote the gas industry. It smells money in the decline of coal, thanks in part to climate concerns," said Frank O'Donnell, president of Clean Air Watch. "It is also a comment that links gas to the Obama administration's rhetoric and seeks to strengthen that political alliance."

Or, for a different take from the former No. 2 at the American Petroleum Institute: "Irrespective of his past, he has stumbled onto the truth. Good for him and ANGA," said Bill Becker, executive director of the National Association of Clean Air Agencies, whose members include state and local officials.

An overwhelming scientific consensus says humans are causing climate change, largely by burning greenhouse gas-emitting fossil fuels. In the U.S., power plants account for 40 percent of emissions.

Republicans and many in the fossil fuel industry, however, reject or are skeptical of that consensus. So Durbin's comments marked progress, some environmental groups said.

Jamie Henn, spokesman for climate advocacy group 350.org, had a mixed reaction. While he called the remarks a shrewd move to buddy up to the Obama administration, which has championed natural gas as a climate-friendly alternative to coal, he also indicated they were a welcomed development.

"Another sign that climate denial is becoming increasingly untenable — and that the gas industry is making a big play to be the clean fuel of the future," said Henn, whose group would rather see all that natural gas stay in the ground because, after all, it's still a fossil fuel, in an email.

To that end, the fuel, which is half as carbon-dense as coal, has become a staple in President Obama's climate strategy.

The fuel's abundance, thanks to a hydraulic fracturing-propelled domestic energy boom, has lowered prices and compelled electric utilities to use more of it. That helped reduce carbon emissions 3.4 percent in 2012 from 2011, according to the Environmental Protection Agency.

The growing clout — or policy alignment, depending on the viewpoint — of the natural gas industry could be seen in the drafting of carbon emissions rules for new and existing power plants, which form the cornerstones of Obama's climate agenda.

Industry and electric utilities lobbied the Environmental Protection Agency to distinguish between facilities with its rule for new power plants, fearing not doing so would crimp construction of natural gas-fired ones. Ultimately, the EPA separated coal from natural gas.

Still, natural gas' emergence in the U.S. is relatively recent.

Just as the hydraulic fracturing boom was taking off in 2008, coal accounted for 48 percent of electricity generated in the U.S., with natural gas amounting to 21 percent of the total mix, according to the U.S. Energy Information Administration. Last year, coal was down to 39 percent of electricity generation, with natural gas rising to 27 percent.

Despite the inroads the industry is making, Durbin spoke of the need to forge better relationships.

"The CEOs of those companies have known their counterparts in the coal industry for over a century," he said of electric utilities. "Those relationships don't really exist with the natural gas industry."