The Green Lantern

Are Carbon Offsets Worth It?

Deciding whether to pay off your holiday air travel.

Last month my husband and I flew to Detroit to spend Thanksgiving with his family, and this week we’re flying to Los Angeles to have Christmas with mine. Should we bother with carbon-offset programs to make up for all that time in the air, or are those things just a racket?

In principle, carbon offsets—which pay for projects that reduce or sequester greenhouse-gas emissions—seem like a pretty appealing idea. Sure, they may seem like papal indulgences, allowing the world’s wealthy to imagine they can do business as usual without causing environmental harm. But given that everyone will be responsible for some carbon, offsets can serve to undo some of the inevitable damage caused by daily life. And by fixing a monetary value on emissions, they help to concretize the hidden costs of flying, eating meat, or whatever else you’re up to.

Carbon offsets make sense only if they really do prevent greenhouse-gas emissions. As this Government Accountability Office report (PDF) points out, a carbon-offset program is likely to be worthless unless it fulfills several requirements. First, it must be real and quantifiable, in the sense that a consumer should be able to figure out by exactly how much the program reduces (or otherwise mitigates) emissions. For example, it’s not enough to say that growing a tree will sequester carbon—we need to know how many tons of CO2 are offset per dollar spent on a project. Second, the reduction or mitigation must be permanent and sustainable. Offsets that pay for underground carbon storage may become worthless if the gas can’t be stowed there indefinitely. Last—and perhaps most crucially—the program’s efforts must spur new, useful activity that never would have happened without your money.

It’s easy to find programs that fail to meet these criteria. Money that is used to buy many of the offsets available on international carbon markets goes toward investments in renewable energy—but it isn’t clear that those projects need the money. Most offsets are verified by a third party, but the verification schemes sometimes have a whiff of Enron about them: The provider usually pays to be certified. The Wall Street Journal and Business Week have found that some carbon offsets pay landfill operators to convert methane emissions into electricity, even though the dumps had already started doing so years ago.

As we look for policy solutions to mitigate global warming, the question of which offsets are legitimate is going to become much more important. Most proposed cap-and-trade plans allow for corporations to purchase offsets in order to meet their obligations. Without strict requirements for verification, this could create a system in which the search for the cheapest available option pushes business toward the lowest-quality offsets. On the so-called “voluntary” market for carbon offsets—i.e., the ones targeted at people like you and your husband—there is a bigger incentive for providers to show they are involved in high-quality projects.

The Lantern believes you should indeed buy carbon offsets—but only after you’ve taken a few other steps first. You might attempt to make up for your city-hopping by cutting back in other aspects of your life—try driving less, eating less meat, or buying fewer luxury goods. Next on the list would be to invest some cash into making your daily life more energy-efficient: better insulating your house, for example, or replacing an energy-efficient appliance when the right time comes. And since it is usually more efficient to cut emissions upstream—at the power plant rather than at your house—your time and money would be well-spent pressing elected officials for a comprehensive plan against global warming.

If you’ve done all that, and you still have money to burn, then offsets are worth the dough. The key is to start off skeptical—demand as much information as possible. Any provider you buy from should make very clear who verifies its offsets, what standard they use, and how they determine that your money will actually reduce greenhouse-gas emissions. (There are about a dozen or so different standards used to verify offsets—some stricter than others—but the aptly named Gold Standard is particularly popular among conservation groups. This World Wildlife Fund-funded report [PDF] gives a good overview of the options.)

You should also look for a provider who tells you exactly how your money will be spent. (It’s your call whether you want to put a picture of the Greenville County landfill on your fridge, however.) Among the more easily verifiable projects are those that capture and destroy methane—see this list, for example—or encourage a switch to cleaner fuels. In general, schemes that plant trees or build wind farms engender a little more skepticism from carbon-market experts, while offsets that sequester carbon from the soil or pay for renewable-energy certificates are the black sheep of the industry.

Above all, use common sense. The whole rationale behind carbon offsets is that worthy efforts to stop global warming cost money, so if you find a provider selling at a cut-rate price, be careful. The Lantern would be very cautious about spending his own green on a provider who sells offsets at much less than $10 per metric ton of CO2-equivalent. You may be able to buy atonement for your carbon sins, but it won’t come cheap.

Is there an environmental quandary that’s been keeping you up at night? Send it to, and check this space every Tuesday.