I've been thinking of purchasing emission offsets to counter global warming, but I read recently that the industry is unregulated and your offsets might not be doing as much good as you hope. Is there a reliable way to do it? --Allie K., Bellingham, Washington

Actually, there is. In February, the Center for Resource Solutions (CRS) launched its Green-e Climate program for all types of carbon offsets so consumers can know for sure that they're getting what they pay for.

Carbon offsets, for the uninitiated, are a way to help you compensate for the global warming emissions you cause. In a nutshell, you "offset" the damage you've done by helping to fund a green project that will prevent one ton of greenhouse gases from being emitted for each ton that you, in effect, have caused.

For example, I try to limit my air travel, since two cross-country, round-trip flights cause more emissions than a year of driving my high-mileage car, according to the emissions calculator at nativeenergy.com. But when I need to fly, I make up for the emissions by purchasing carbon offsets that go toward constructing new wind turbines. Other offsets you can buy support solar panels and reforestation efforts.

Before February, the industry was essentially unregulated, and if you bought carbon offsets you were pretty much taking it on faith that the money would go to something good. CRS created Green-e Climate so consumers wouldn't have to go into the transaction blindly. "When you buy something from an offset provider, we want to make sure you're getting what the provider says you're getting," says Lars Kvale, who manages the program.