Eco Etiquette: Is The Carbon Footprint Passe? 5 Global Warming Offenders to Know Now (PHOTOS)

Send all your eco-inquiries to Jennifer Grayson at Questions may be edited for length and clarity.

Somebody said to me that carbon footprint isn't the most important thing anymore, that there are other greenhouse gases out there that are more dangerous. Is this true?


Ah, the illustrious carbon footprint. Esteemed by tree huggers as the true marker of one's impact on the planet and reviled by global warming skeptics as nothing more than phraseology poppycock, the expression has become so embedded in the environmental lexicon that a Google search for the term revealed no fewer than 4,240,000 results (nearly three times the hits for "global warming hoax," FYI).

There are dozens of websites devoted to determining -- and diminishing -- one's own magic number. At, for example, you can calculate the carbon footprint of your wedding, by providing information about out-of-town guests traveling to the event and hotel rooms required. Via the Nature Conservancy site, you can even make monthly contributions to offset a portion of the carbon emissions you aren't able to reduce.

But what does carbon footprint mean, exactly? And is it possible that a mere two years after making it into Merriam-Webster, the phrase could be passé?

I say yes. But before you throw the big green book at me, some brief background:

The carbon part of carbon footprint refers to carbon dioxide (CO2); i.e., a chemical compound that has increased in the atmosphere since the burning of carbon-based fossil fuels like coal and oil began during the Industrial Revolution. It's those intensifying concentrations of man-made CO2 around the planet, as you likely know, that 97 percent of climatologists have linked to global warming.

My objection to the phrase comes down to sustainable semantics: What most people don't realize is that this catch-all term is meant to include the impact of other greenhouse gases that can be even more powerful -- in some cases over 20,000 times more so -- than the common carbon.

Carbon dioxide is used merely as the unit of measure; the carbon footprint of a hamburger, for example, would also likely take into consideration a cow's methane emissions, which would then be converted into the amount of CO2 ("CO2 equivalent") that would cause the same effect on global warming. But by referring to this as carbon footprint alone, I think we're missing the opportunity to raise awareness about those other potent greenhouse gases.

Take a look at these five global warming offenders: