That's how author and sustainability guru Paul Hawken responded when I asked him during FORTUNE's Brainstorm Green why a small-is-beautiful guy agreed to work for huge companies like Wal-Mart and Ford. And I like to think that's why nearly 300 business executives, NGO leaders, activists and government types came to our conference on business and the environment earlier this week.

They were a diverse and occasionally disputatious group, which is exactly what we want: We had speakers from Greenpeace and the Rainforest Action Network, as well as Big Oil , the nuclear industry and American Electric Power, the nation's No. 1 emitter of global warming pollution. But while there was disagreement over what path to take, there was broad consensus that business needs to find ways to become more sustainable.

Here are some of my takeaways from the event. One caveat -- the quotes below were taken down on the run and may not be word-for-word perfect but they are close.

Bill Clinton doesn't mind getting his hands dirty. Where do you find the former president these days? Occasionally, mucking around in the waste of cities like Lima, Mexico City and Lagos. "Whenever I think of an urban landfill, I see it not just as an eyesore and a contributor to global warming but a source of great wealth," Clinton said, during the closing plenary. His Clinton Global Initiative on climate change, he explained, is training scavengers in Lima to be recycling workers, given them a salary and health care and encouraging them to become part of a "new industry in glass and metals."

Clinton's speech was a state-of-the-union style laundry list, long on details/solutions. He got all charged up about energy efficiency (hard to do) as he talked about retrofitting the Empire State Building, described extensive efforts to get cities to curb their carbon emissions and explained how he is helping to make college campuses more efficient.

"The most important thing you can do if you are not a member of the U.S. Congress," he told the crowd, "is to show that the change we are all seeking is good economics." He had a couple of odd ideas, suggesting that the states of Nevada and Arizona or maybe a Caribbean nation become "energy independent" to show the world that it's possible. Clinton looked good, by the way -- he wore a pair of Texas cowboy boots and hustled out of the hotel after his speech and a photo session to squeeze in a round of golf.

Some big problems, corporate America can't solve. Fisk Johnson of SC Johnson, Jeff Hollender of Seventh Generation, Bill Valentine of HOK (big architecture firm) and Carl Bass of Autodesk (design company) joined me for a panel called Re-Imagining Consumption. The question put before them was simple but important: How can companies grow their revenues and profits while shrinking their environmental footprint?

I thought we'd get into a conversation about cradle-to-cradle products that companies sell, or new business models like ZipCar. But we veered into a discussion of overconsumption after someone mentioned the oft-cited fact that Americans make up roughly 5 percent of the world's population and consume 25 percent of its resources.

That's obviously a problem, and since companies are invented to solve problems, I ask them if there is a business opportunity there. They couldn't see one, although Bill Valentine said HOK often asks its clients whether they really need a new building, Carl Bass said Autodesk is incorporating sustainability questions into its software, and Fisk and Hollender both talking about "greening" their products and packaging.

The truth us, it's hard to imagine even progressive companies (except for recycling firms) coming up with products, services or new business models around buying less stuff. This tough job is probably best left to parents or religious leaders.

Environmentalists should reconsider nuclear power. I'm told there was a long and animated dinner conversation one night during which two leading thinkers of the sustainability movement -- Janine Benyus of biomimicry fame and Ray Anderson of Interface -- peppered Alan Hanson, an executive from Areva, the big French nuclear power company, with probing questions about nuclear power. I was pleased to hear that because I've thought for some time that environmentalists need to rethink their almost-religious opposition to nuclear power. (I'm going to write about this in more detail next week.)

If the problem of climate change threatens the very existence of human life on this planet (and it does), shouldn't we reconsider nukes? Of course we should. We're going to need baseload power and while a combination of efficiency, renewables and battery storage might get us where we need to go under a best-case scenario, I don't want to bet the planet's future on a best-case scenario. It's likely we'll face a choice between nuclear and so-called cleaner coal. I'm not sure where I come down on that.

During a panel on nuclear power (read David Whitford's account here) that focused on its costs, I learned that Steven Chu, the energy secretary, is an advocate for nuclear while Carol Browner, the climate czar, is an opponent. President Obama has punted on the issue -- he hasn't said much of anything, at least according to our panelists. While Browner's the more powerful figure in D.C., Chu is a brilliant and impressive guy, not to mention the only cabinet member with a Nobel Prize. I'd love to be a fly on the wall when they and Obama get together to talk about nukes.

I'm still not convinced about green jobs. Van Jones, the White House green jobs czar, spoke at Brainstorm Green and he managed to be both inspiring and utterly charming. But he couldn’t come up with a clear-cut definition of a green job. That's not surprising. Consider the farmer who grows corn for popcorn. He's a mere farmer. His buddy up the road who grows corn for ethanol? Green job, I presume.

Clinton, too, has hopped on the green jobs bandwagon: "I've always believed that work is the best social program," he said. "Saving the planet from the threat of climate change will create more jobs, more ideas, more interdependence than anything else we can do."

Hmm. Fred Krupp of the Environmental Defense Fund said the best economic studies about the impact of a cap-and-trade program to regulate greenhouse gases project that the long-term impact on GDP will be very, very slight. But if GHG regulation has even a slight negative effect on GDP, how can it create more jobs?

It's time to stop feeling guilty about business travel. Brainstorm Green was held at the Ritz Carlton in Laguna Niguel, California -- a spectacular place overlooking the Pacific. We had some fabulous meals -- prepared by organic chefs -- and I got up early to run (a little) each day. At night, I opened the door to my hotel room and fell asleep to the sounds of the waves and an ocean breeze.

As it happens, we were at ground zero for the crisis in business travel. Next door was a St. Regis where AIG held a meeting last fall that made national news and led to the cancellations of hundreds of business meetings. Luxury hotels and their working-class employees are suffering. What's good about that?

More important, there was value in getting 300 people together in a relaxing place for a couple of days to talk about things that matter. We learned. We met new people. We built relationships. We showcased leading thinkers and doers, perhaps inspiring others. Maybe a startup that needed money raised some. We may live in an always-connected, everything-linked world, but you can't do those things very well on email or over the phone or in a video conference.

_{Neurons – Image by Dr. Jonathan Clarke, Wellcome Images; CC licensed by Flickr user LoreleiRanveig.}