Our sleek, glass-box buildings of today tend not to take climate into consideration. Were ancient buildings more energy efficient?

As with an ordinary tattoo, Heather Clark said, the dye would be injected beneath the skin of someone with diabetes.

"Some people experiment with drugs and get addicted, and others do not, and I think you don't know ahead of time," cautions Joanna Fowler.

Carl Imhoff on president Obama pledged three billion dollars in U.S. stimulus funding to transform the old electric grid into a Smart Grid.

Catherine Badgely believes that organic farming can help farmers increase their local productivity, and the well-being of their own local communities.

Greenbaum is president of the Health Effects Institute, an independent research organization heavily funded by the EPA studies greenhouse gases.

Renewable energy may be the ideal, but it doesn't happen overnight. "In the meantime, we must start managing the CO2 emissions from fossil fuel emitting power stations, refineries, steel plants, and so on. And carbon capture and storage is the only technology that allows us to do that," says John Barry.

"There's a very tense, polarizing debate between people who believe big agribusiness and organics are enemies of each other," says Jon Foley, "The world needs both and we need the lessons from both."

Listen to Peter Moeller talk about a sea sponge he discovered that could help fight antibiotic-resistant bacteria.

Elke Anklam talks about the possible pros and cons of using nanotechnology in food products. The FDA is assessing their safety.