Some 500 people drive or fly to the Pop!Tech conference on Maine's scenic midcoast from all over the US, and a few from overseas. They burn a lot of fossil fuels to get here. To make up for that, the conference is sponsoring solar power projects by the Solar Electric Light Fund that it says will save twice the amount of carbon emissions that will be expended by the conference and its attendees.

Climate change and where tomorrow's energy will come from after fossil fuels are spent has to be on any agenda grappling with the great issues. No exception here. As one speaker put it: Al Gore was wrong about climate change and clean energy: It's much more serious a problem than he says.

Tom Friedman, the New York Times columnist and author of "The World Is Flat," used his 20 minutes to basically sound out the themes in his book and columns. They're powerful themes. We have to redefine what we mean by "green," he says. It's not all granola crunching and "girly men," he says, it's not something "vaguely French." Green, Friedman says, is the new "red, white, and blue," patriotic and capitalistic. If we don't solve our oil addiction, he says, we're going to "heat up, choke up, burn up" this planet. The Chinese are already recognizing they can't follow the US model. A Green China, he says, is going to pose a greater challenge than Red China ever did.

Friedman knows how to create memorable images with words, giving his ideas intellectual muscle and mindshare. So do nearly all the presenters, which make them not only thinkers but impressive communicators as well.

Stewart Brand continued the green theme later Thursday by outlining where the environmental movement may be headed. Those with a romantic attachment to Mother Earth will still be on the front lines, but increasingly they're being joined by hard-headed scientists and engineers. New and better data is pushing everything. The scientists and engineers, many of whom still feel uncomfortable being ID'd as "green," are more likely to recognize that humans are already "Terra forming," or changing the natural world using science and technology, to meet their demands. (So we better do it right, he adds.) They're going to be more open to nuclear power if the alternatives are really worse. (Maybe we don't need a 10,000 year solution for nuclear waste, but a few-hundred year solution will do. Presumably the world and scientific knowledge will be much more prepared to deal with it by then.)

One billion people now live in squatter cities, the vast slums that surround cities, especially in the developing world. Two billion more are expected. That's trouble in some obvious ways, but surprisingly, perhaps, there's another side. In the slums, everything is recycled, much less fossil fuel is consumed per person, and underneath the chaos, entrepreneurs come up with innovative ideas to make it all work.

Seeing what's happening clearly is always the first step. But follow-up sessions from people sharing innovative ideas, like environmental journalist Alex Steffen, show there's no excuse not to go beyond hand-wringing. "Junk tagging," for example, is just one idea for an Internet-connected world. Why not point out online the location of one person's junk to everyone? It might be someone else's treasure, he says. Technology can "dematerialize" some of the damage done by an industrialized society. Netflix, the mail-based video company, not only has a profitable business plan: It also eliminates car trips to the video store and the video store itself, along with all the energy and materials that are needed to build and maintain it.

We gain status and identity from possessing objects, but services like car sharing programs in big cities show that the need is really something else, he says. We need to get someplace. Could dishwashers be shared too? Power drills? "We want the hole, not the drill," Steffen says.

Better product design can play a part, too. What if old cellphones could be put in a 350-degree oven for a few minutes and simply pop apart into their constituent parts for easy recycling? With the one billion cell phones expected to be sold worldwide next year, that's a compelling idea. (Get used to recycling going mainstream. "Virgin" raw materials will be used up in the next 30 to 70 years, says materials researcher Blaine Brownell.)

Sometimes no new technology is needed at all, only a better understanding of human nature. Homes use less energy when the electric or gas meter is put INSIDE the house where residents see what's happening. Same thing for cars: Drivers whose cars show how many miles per gallon the car is achieving actually drive in a more fuel-efficient way.

Apparently, knowledge IS power.