Two months ago, a reporter interviewed me for a story about the sustainability of “green” news-whether journalists’ current interest in environmental journalism is the sign of enduring social change or just a passing fad. The reporter’s employer, Environment & Energy Publishing, is now banking on the idea that this eco-consciousness does indeed have legs.

Two weeks ago, E&E, which has produced the popular online news sites Greenwire and E&E Daily for a decade, launched ClimateWire, the sixth installment in its pantheon of publications, which also includes E&ENews PM, E&ETV, and Land Letter. Like its sister pubs, ClimateWire tackles its subject from a multitude of angles, including domestic and international political, business, and scientific efforts to explain, mitigate, and adapt to global warming:

“Our flagship publications, Greenwire and Environment & Energy Daily, will continue to cover climate and other energy and environmental issues as usual,” E&E editor-in-chief Kevin Braun said in a press release. “ClimateWire will add range, depth and insight to our coverage of this critical area-an area that will only grow in scope in coming years, as both a policy issue and an economic reality that will affect just bout everyone.”

Braun elaborated in an interview:

We’ve been kicking around the idea of a publication focused in the energy, air and climate area for probably four or five years now. We weren’t sure what the mix was, where the focus was going to be, but we felt like there was an increasing need to concentrate on those areas specifically. But ultimately, climate started to become such a dominant issue, and it has such a huge impact on the energy policy game and energy markets, that we decided to focus on climate and get the energy stuff in on the back end.

Braun and his business partner, Michael Witt, founded E&E Publishing in 1998 with seven employees, and have steadily built the company ever since. But the swiftest growth has occurred during the last six months, according to Braun, during which time E&E has climbed from a staff of thirty-five to fifty. Still, the outlet is not very well known among general, mass-market audiences. It has around 40,000 “regular readers,” most of whom come from the slightly less than 2,000 institutional subscribers that comprise local, state, and national governments, embassies, major corporations, universities, think tanks, law firms, consultants, lobbyists, and environmental groups.

“I was on my way to being a journalism professor when I left The Wall Street Journal,” said veteran journalist John Fialka, whom Braun hired to run ClimateWire after he left his former employer in January. “I didn’t even know who they were. I began looking at their stuff, and they work hard. They go at it. They specialize and they’ve got bright people. So I decided that’s a team I’d like to join. And the idea of a start-up in a new area-I’d never been an editor before and that sounded like something I should try.”

Fialka says that so far, he has enjoyed the depth of coverage that comes with moving from a mainstream to niche readers. “It’s a fairly elite audience,” he told me. “They know the issue. You can write in more detail for them, and they appear to be hungry for that.”

Actually, E&E Publishing might have launched ClimateWire when the editors introduced the idea a few years ago, but they decided to launch E&ETV and E&ENews PM (both in 2005) first. By the time they’d gotten those projects well established, the next move was obvious. “Climate,” Braun said, “had become a really, really big deal, obviously, in those intervening couple of years - post [United Nations’ climate negotiation in] Bali, and Congress actually trying to move a bill in a fairly serious way - it was the tipping point for us.” Plus, E&E had grown, too, and was finally in “the financial position” to be able to hire people like Fialka. ClimateWire now has its own staff of five experienced reporters, as well as senior contributors from Greenwire and other E&E publications.

“We run fairly detailed analyses on what stories are the most popular; what stories are being read the most; and what types of people are interested in them,” Braun told me. “Climate was just such the dominant issue in terms of popularity. It wasn’t even close.”

Given that demand, E&E Publishing opened single-reporter bureaus in San Francisco last fall, and in New York last month. The company also has stringers in Europe, but Braun hopes to open a fulltime bureau in either London or Brussels and, after that, somewhere in Asia-perhaps Beijing, Hong Kong, or Singapore. Braun is sending a team to cover the summer Olympics in China and scout out permanent locations at the same time.

Curtis Brainard writes on science and environment reporting. Follow him on Twitter @cbrainard.