Then there's Jim Sears, a systems engineer whose Boulder, Colorado–based A2BE Carbon Capture startup is working with scientists from New Mexico's Sandia and Los Alamos national labs, among others, on the DARPA solicitation. (Sears has worked with NASA and the National Institutes of Health, and he helped perfect the Hump-O-Meter, a device worn by cows that detects sexual activity, so that it would be strong enough to "withstand the rigor of the blissful moment.") For full-scale algae-fuel production, Sears has designed closed systems of 50-by-450-foot clear plastic photobioreactors (think water-bed bladders full of algae). With 16 to 32 million acres of photobioreactors spread around the world, Sears believes, some 3.66 gigatons of CO₂ could be consumed each year. That's one-seventh of the way toward halting the world's emissions at 1990 levels by 2050. Sears's project, like the others here, is planned largely for nonarable land using mostly brackish water.

No one, of course, believes that algae can take us all the way home. "No matter how gaga or depressed you are about biofuels," says Daniel M. Kammen, the founder of Berkeley's Renewable and Appropriate Energy Laboratory, "solar, wind, and, whether you like it or not, nuclear and hydro are going to be much bigger pieces in the end. If the forecasts coming out of my lab are correct, it would be crazy to truck liquid fuels around in 20 or 30 years."

Still, it's encouraging that tin-hat solutions like algae and garbage, things that seemed downright wacko not so long ago, are being seen as serious parts of the energy revolution. "The changes that I think we're going to see between the year 2000 and 2030," says Douglas Kirkpatrick, a program manager for DARPA's Strategic Technology office, "will be very similar in magnitude to the changes we saw between 1900 and 1930. In 1900, man had yet to fly, and the common mode of transportation was the horse."

In other words, he's saying, be patient. The future is coming—we just have to get it out of the trash. Me, I've got a gallon of algae biodiesel on the way from a catfish farm in Alabama. And I've upped my chocolate intake considerably. Never underestimate the possibilities of a little belly fat as a renewable resource.