James Gustave "Gus" Speth, Dean of the Yale School of Forestry and Environmental Studies, has been at the forefront of the American environmental movement for nearly as long as there's been such a thing. After co-founding the National Resources Defense Council in 1970, while in his final year at Yale Law School, he went on to chair President Jimmy Carter's Council on Environmental Quality from 1977 to 1981; found the World Resources Institute, a green think tank, in 1982; act as a senior environmental adviser to President Clinton's transition team; and head the United Nations Development Program from 1993 to 1999, when he left to assume the Yale post. Besides guiding the environmental leaders of tomorrow, Speth, who drives a Prius and has a bank of photovoltaic panels in his Connecticut yard, has authored three books in that time, including his potent dissection of our failure to address the issue of climate change, Red Sky at Morning. Through generational and political shifts in the environmental movement, Speth's voice, which retains the distinctive tones of his native South Carolina, has been a constant source of reason and measured optimism, as well as the occasional laugh. He took time out from a day of hosting Sir Nicolas Stern, the British economist who has calculated the economic ramifications of global warming, to speak with Outside about his career, environmental politics, and some of his favorite outdoor spots.

OUTSIDE: Thanks for speaking with me. I hope not to take up too much of your time.
SPETH: We can always talk again. It just turned out that the schedule today got screwed up by mistake—this famous report on the climate issue [the Stern Review on the Economics of Climate Change (2006)], the guy who did it, Nicolas Stern, arrived at Yale and is giving presentations all day today, and so I've been tied up with that, since it's kind of my area.

Obviously you're a pretty busy guy, but I was curious what the leisure time balance is in a job like yours and what you enjoy doing in your spare time.
Well, since our children were old enough to do anything—actually, no, since before they were old enough—we dragged them into the Everglades and Okefenokee and the Boundary Waters canoe area, [laughs] and when they got big they swore they'd never get back in another canoe, which didn't turn out to be true. But we've always had an affinity for outdoor activities. I've found that the national parks are really great if you get off of the highways and walk a few feet-more often than not, there's nobody there. We hiked all the way to the Great Falls of the Yellowstone, for instance, and I think we were the only people there looking at it. We've been everywhere. Last summer we went up to a place that was fantastic, I thought, Newfoundland, and climbed Gross Morne Mountain and hiked the hills on the western side of the island, and it was beautiful. There were more moose than people. One of our favorite places was a little Canadian provincial park called Assiniboine, which is tucked away sort of near Banff and Jasper, a wilderness park, and it was really spectacular. And we've been to the tropics and down to Patagonia a couple of times, always trekking. So the answer is, basically, my wife and I really love hiking.

You've worn a lot of different hats over the course of your career. Do you consider yourself primarily an environmentalist, an administrator, an educator, an activist, all of them?
Well, I think if you look at what I've done, the environmental theme has been consistent throughout. Less so during my six years in the UN when I was more focused on development than the environment, but we had the UN's largest program in sustainable development and environmental development, and we built it up, so there's been a very consistent focus on environmental issues. I'm a proud environmentalist.

When you co-founded the NRDC, you were still in law school. Did you have in mind then that environmental advocacy would be this lifelong calling?
I guess I saw it as a long-term thing, but I didn't know I'd stick with it for the whole time. And I think the reason that I've been able to do that is that I've worn this green hat in a lot of different roles. The NRDC is an advocacy group, and then we built the think tank in Washington, the World Resources Institute, and then the Carter administration, and then the UN, and now here [at Yale] for eight years, I can't believe it.

Is it safe to say that at the outset you didn't have any idea that someday you'd be dean of the Yale School of Forestry?
No, no. [laughs]