His voice won’t be heard during arguments in the Supreme Court’s major global warming challenge this month, but Matthew Pawa has been a leading voice in crafting the public nuisance approach to climate change litigation for nearly a decade.

Pawa represents three land trusts in American Electric Power v. Connecticut — actually two lawsuits against five utilities producing the largest amounts of carbon dioxide in the nation. New York Solicitor General Barbara Underwood, counsel to six states and New York City, will make the case for both groups on April 19.

A graduate of the University of Pennsylvania School of Law, Pawa cut his legal teeth as a prosecutor in Burlington, Vt., but he always intended to go eventually into environmental litigation.

“I loved my job as a prosecutor,” he said. “It was one of the best jobs I’ve ever had. But I had always been interested in environmental law and environmental protection. I majored in environmental science in college. It just took me some time to figure out how to do it in a way that allowed me to work on the kind of cases I wanted to do.”

After what he called “phenomenal” experiences at Crowell & Moring and Cohen Milstein Sellers & Toll, Pawa opened his own firm in Newton Centre, Mass. Aided by a grant from the Civil Society Institute, a Newton-based think tank interested in climate change, he began exploring the basis for climate change litigation.

“I started to have discussions with folks around country who were interested in pursuing this,” he recalled. In the fall of 2001, two months after opening his law firm, he received a call from the Connecticut attorney general’s office to come and talk about global warming. “It was unbelievable.”

Pawa’s clients in the Supreme Court case are the Open Space Institute, the Open Space Conservancy, and the Audubon Society of New Hampshire. He is also co-lead counsel in another public nuisance climate change suit: Village of Kivalina v. Mobil-Exxon Corp., undergoing briefing in the U.S. Court of Appeals for the 9th Circuit.

The Land Trusts’ properties provide rare habitat for various animals and plants, including ecologically sensitive areas of coastline, riverfront land, wetlands, and hardwood forest, he tells the Supreme Court in his brief opposing the power companies.

“For example, a property at Bellamy River in Dover, New Hampshire, includes an estuary that provides wintering ground for bald eagles, as well as habitat for migratory birds and numerous fish species,” he writes. “Another property, the Sam’s Point Preserve in Ulster County, New York, includes the only extensive community of dwarf pine trees on bedrock known to exist.”

The trusts’ properties, because of location, are particularly vulnerable to present and future effects of global warming, such as flooding from rising sea levels.

The path to the Supreme Court through the public nuisance avenue has been “hard,” he conceded. “We started looking at this in 2001-2002. Global warming was not as nearly as huge a problem as it is now. Trying to understand the science and a complex area of law, trying to put together a case that would survive the onslaught of motions by the best attorneys in the country — it has been very hard.

“At the same time, we’ve been very gratified by the progress of the case so far,” he added.

Pawa and others expressed disappointment that the Obama Administration is on the side of the utilities in the case. “We had always hoped that the larger interests of the United States as a whole would call for a different approach,” he said. “That’s not the case, so off we go. We have to overcome the institutional force of the solicitor general’s office now.”

But that opposition and the recusal of Justice Sonia Sotomayor from the case (viewed by many on Pawa’s side as a disadvantage) have not discouraged Pawa.

“We always felt we had a strong case,” he said. “We understood what the defenses would be and we crafted a case that would survive all of those challenges. We won before a panel of two, well-respected judges, who can’t be accused of being activists. “We feel we can win this in front of any judge who can keep an open mind and pay attention to the law.”

And he keenly recognizes what hangs on the outcome. “Just the fate of the world,” he chuckled. “Not much.”

Marcia Coyle can be contacted at mcoyle@alm.com.