When contemplating the world's environmental problems, it's sometimes hard not to feel like humanity is screwed. But then you attend an event like Future Cities, a panel of sustainability experts held last night at the World Science Festival, and it seems like we might just figure out how to thrive on this planet after all.

First up was Peter Head, director of sustainable urban engineering firm Arup. He talked about a model city now under construction in Dongtan, China. When finished, it will be the world's first sustainable city: an eco-paradise of open space, mixed neighborhoods and convenient transportation.

Head said that the Chinese government has commissioned nine cities altogether. "China decided it had to change," he said. To which I was equally optimistic and skeptical: It's wonderful to think that China's government realizes the importance of sustainability, but when they pay your bills, it wouldn't make sense to say otherwise. But Head later added, "Investment banks take experimental green cities seriously as an investment. They didn't one year ago."

(See Wired's profile of the city at Dongtan here.)

Next came microbiologist-turned-agro-revolutionary Dickson Despommier, intellectual godfather of vertical farming: skyscrapers full of gardens that produce our food and free farmland to return to CO2-sequestering forests. It's a no-brainer solution for a global population that will be 80 percent urban by 2050 and is in desperate need of a climate change fix: Read my interview with Despommier here

Following Despommier was Majora Carter, the South Bronx born-and-raised environmentalist and MacArthur genius grant winner. She talked of the disproportionate pollution burden borne by the poor – a burden that is both physically and mentally damaging, exacerbating a cycle of poverty, crime and frustration. Carter believes that green-collar jobs can break this cycle: she founded SmartRoofs, a green roofing company, and her nonprofit Sustainable South Bronx offers green-collar job training.

Columbia University architecture professor and former MIT Media Lab Smart Cities wonk Mitchell Joachim spoke next. I'm not sure exactly what I think about his talk. Pieces of it – such as the City Car he helped design – were inspiring. Other parts, such as the Peristaltic City, seemed less about genuine sustainability than gee-whiz brainstorming given a green veneer. Then again, gee-whiz brainstorming is an important part of the creative process, and helps colonize territories of the imagination that can later be developed more practically. (And I really, really want to live in a Tree Hab someday.) But stuff like the Ecotarium

\– a cute video of major cities disembarking from land and setting sail for the North Pole – felt frivolous on the same stage with the real-world struggles of Despommier and Carter and Head.

Finally there was green materials guru Blaine Brownell (pictured above), who gave a Willy Wonka-esque demostration of sustainable building products: spherical solar cells, flexible solar cells, zero-energy wallboard, luminescent gravel, kinetic glass, self-healing plastic, structural textiles, air-scrubbing paint and self-cleaning glass.

In short, a whole lot of green ingenuity was on display – and this is just the beginning. Just think how the field will blow up when, as

Peter Head hinted, it gets seriously profitable.

See Also:

WiSci 2.0: Brandon Keim's Twitter and Del.icio.us feeds; Wired Science on Facebook.