Shopping around for carbon offsets

What are carbon offsets? Umbra Fisk describes them like this:

"Wouldn't it be great if you could calculate how much carbon you emit, and somehow remove that carbon from the atmosphere? You can't, but you can offset (maybe a better term would be compensate for) your carbon emissions by supporting projects that will reduce overall global carbon emissions. For example, you can give money to an organization building windmills, and the organization in turn guarantees that the wind power generated with your funds will replace your equivalent carbon emissions. You use an emissions calculator provided by the company, and the company has a set fee per ton of "offset" carbon."
(Umbra's full article: http://www.grist.org/advice/ask/2007/10/15/index.html).

I recently received a CleanAirPass (one particular carbon offset brand) as a gift. Theoretically, the little sticker inside my windshield means that I have sufficient carbon credits to render our family vehicle 'Carbon Neutral' for one year. Neat idea, but I haven't yet wrapped my head around the exact benefit to the planet. More thinking required on this.

Regardless, it appears to be worthwhile to do some shopping around when considering carbon offsets. Some organizations are better established than others, and it's important to find an organization with a philosophy you can live with. To help you shop, (further from Umbra's article):

"The Voluntary Carbon Offsets Information Portal, of the Tufts Climate Initiative and the Stockholm Environment Institute, is a nice clear compilation of basic information about carbon offsets, their purpose, and when to consider using them. They describe the criteria by which you should judge any company selling offsets, and evaluate and recommend 13 specific companies. Take what you've read in Gristmill and read the VCOIP information, and you may be able to make an offset shopping decision about which you feel solid."

For an additional rating of carbon offset companies (complete with a whole crapload of methodology), check out Clean Air-Cool Planet's Consumer's Guide to Retail Carbon Offset Providers.

If you really want to make a difference, choose not to own a car at all. But if you're not quite ready to do that and, like me, you need to find a way to mitigate the eco-guilt that comes with owning a car, perhaps carbon neutralizing yourself is the way to go.