SEATTLE – Some companies are starting to show customers a product's cost to the environment -- right next to the price tag.

Shoe manufacturer Timberland is putting something called a "carbon label" on select styles of footwear. It's a "green" index that looks similar to the nutrition label on food.

"We talk about things like the amount of renewable energy we purchase, how much energy goes into manufacturing a pair of Timberland shoes," said Besty Blaisdell, Timberland environmental steward.

The process creates a "carbon footprint." It's a number that tells you how much carbon dioxide is generated to produce that shoe from start to finish.

"So imagine, cows on a field to finished product, meaning the shoe is off the conveyer belt and into the footwear box at our factory," Blaisdell said.

Seattle marketing expert Michelle Barry believes manufacturers need to teach consumers what "carbon labels" mean.

"At the end of the day consumers are having a difficult time even understanding this whole idea of carbon or carbon emissions," said Barry, of the Hartman Group.

The average American household of two puts out more than 20 tons of carbon dioxide each year, mostly from using electricity and driving. A gallon of gas alone releases 20 pounds of carbon dioxide into the atmosphere. Producing a sneaker releases 88 pounds of carbon dioxide. A clog? Sixty-six pounds.

Other companies are starting to use eco labels. Pepsi is trying them on potato chips in Europe and some British retailers are slapping them on shampoos.

There are other things consumers can do to shrink their carbon footprints day-to-day:

-Use less electricity at home and work.

-Drive less and make your next car diesel.

-Fly less.

-Reduce consumption of red meat.

-Eat produce grown close to home, so it doesn't have to be shipped so far.