Nine billion people: Business bonanza or Armageddon?

Think on the bright side. Nine billion people is a lot of people to sell stuff too. But can the world handle it?

At Fortune's Brainstorm Green conference Wednesday, business and environmental leaders were cheery.

"I definitely vote for opportunity," said Glenn Prickett, chief external affairs officer for the Nature Conservancy. "I don't think you can be in the conservation community and not be an optimist."

"We all must think of it as MORE

Let them eat organic

You see them at the supermarket - plump, ripe red tomatoes that look so healthy and tasty. But then you realize they're organic, and likely to cost twice what the shabby slicing tomatoes do. So back on the shelf they go.

Yet buying organic is not only good for the body, it's good for the earth. So how to bring more organic food to more consumers at a cheaper price?

Expand research MORE

Water: The most undervalued resource

Water...it sustains all life.

Yet consider this: Worldwide, 80 countries suffer from water shortages, including highly productive agricultural areas in northern China, the western United States, and northwest India.

Four thousand children under the age of five die each day from water-born diseases. Almost 40% of all the water used in agriculture - the biggest consumer of water by far - is wasted.

But only 1% of venture capital money is going into MORE

Fish you can feel good about eating

Lots of people love seafood. But most people know the oceans are overfished, and no one wants to be an eco-jerk. So which types of fish are OK to eat, and which should we avoid?

The answer: generally small fish that reproduce quickly and don't eat meat are OK. That means catfish, tilapia and carp, among others.

"It has to be low on the food chain," Sylvia Earle, explorer in residence at MORE