Today! Free Starbucks Coffee if You Bring a Reusable Mug

[Photo: Starbucks]

In honor of Earth Day, participating Starbucks will fill your reusable coffee mug with brewed coffee for free. You even have your choice of hot or iced! They ran the same promotion last year and saved over a million disposable cups.

So we wondered: Is it really that good for the environment? What's the carbon footprint of a cup of coffee, or a million free ones?

A plain old cup of coffee (without cream or sugar) has a carbon footprint of , which, if they give away one million of them, is the same as the emissions generated by four cars over the course of a year. Which sounds like a lot? Especially considering some of those people wouldn't have gone to Starbucks without the freebie deal.

But it's also a million disposable cups, lids, and sleeves that aren't being thrown away, which is an ostensibly good thing. The coffee chain has additional initiatives in place to reduce their footprint. So, happy Earth Day, everyone!

· Bring in Your Travel Mug April 22 - Get a Free Brewed Coffee [Starbucks / Facebook]
· All Starbucks Coverage on Eater [-E-]