What is my breakfast orange juice doing to our planet?

It isn't good news unless my orange juice is organic. The biggest single cause of greenhouse gas emissions across the entire orange grove to juice glass industry? The artificial fertilizer that insures a big and profitable crop. That's the result of a study paid for by PepsiCo, one of the world's biggest orange squeezers.

Taking the first step, Pepsi's Tropicana division wanted to find out where the emissions were created. Said the company chief, "The main thing is helping us figure out where the carbon is in the chain."

PepsiCo is among the first that will provide consumers with an absolute number for a product's carbon footprint, which many expect to be a trend. The information will be posted on Tropicana's Web site. The site already has the company's pledge to pursue sustainability.

Other corporations making public efforts to curtail their carbon footprint: IBM, Nike, Coca-Cola, BP, Google, Yahoo and Dell. The latter three promise to become "carbon neutral."