Editor's Note

CARBON FOOTPRINT.

The term is hard to avoid these days. Companies are throwing it around as a marketing ploy, determined to show how green their products are. Consumers are encouraged to use the number to rethink how they buy and live. The fate of the Earth, we're told, depends on reducing it.

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So, maybe it's time to ask some basic questions. Such as: What exactly is a carbon footprint? How do you measure it? And how does the carbon footprint of one product compare with another?

The Journal's environmental expert, Jeff Ball, set out to answer those questions in his cover story. By looking at the carbon footprint of six everyday products, Jeff gives us a window into this crucial but often misunderstood concept.

He explains what the numbers mean, and how they are calculated. He reveals why some of the conventional wisdom is false. And he discovers how the way we use products is often more important than the products themselves.

The term, after all, is hard to avoid these days. So you may as well understand what everybody's talking about.