When Dave Muirhead started a courier service in Charleston in January, he wanted his company to be a local pioneer for environmentally friendly business practices. He decided to take two courses of action: he bought a hybrid car and began purchasing carbon offsets.

From every delivery made by his company, Greenlight Delivery, Muirhead paid to have a tree planted either in Honduras, California, or part of the Tennessee River Valley that was damaged by Hurricane Katrina. The idea, Muirhead says, was to achieve carbon neutrality, as the CO2 consumed by the trees during photosynthesis would equal out, or offset the carbon given off by his two delivery vehicles.

“I think you can have a sustainable life, a profitable future, and at the end of the day you can still feel good about yourself,” he says.

The idea behind carbon offsets is simple — an individual or a company cancels out their carbon emissions by paying a company to invest in projects, like reforestation or renewable energy, that will reduce the amount of CO2 in the atmosphere. The overwhelming majority of carbon offsets are purchased by large corporations, but the popularity of voluntary offsets like the one used by Muirhead is growing, driven in part by increased media coverage.

Despite the recent hype, not all environmental experts are on board.

“I don’t think offsets are particularly useful,” says Joseph J. Romm, a prominent environmental blogger at Climateprogress.org and a senior fellow at The Center for American Progress, a liberal think tank.

Critics like Romm have pointed out several problems with carbon-offset projects, particularly those like the one used by Charleston’s Greenlight Delivery which rely on planting trees. As noted by Adam Stein in the environmental blog Grist (www.grist.org), trees grow slowly and can take as long as 40 years to reach their full carbon-sequestering potential. By that time, writes Stein, we could “either be living in hurricane-proof seaside bunkers in the Rockies or flying around in hydrogen-fueled jet cars.”

Romm’s basic problem with offsets is that they present a way for individuals to buy a guilt-free conscience on the cheap and avoid confronting what’s really needed, namely, a “fundamental change in the game.” That’s the sort of thing that requires a lot of work and takes a long time to happen — advocacy groups have to be formed, politicians have to be brought on board, laws have to be passed, regulations have to be put in place, and the nation’s entire energy sector have to be shifted away from fossil fuels. It’s not that Romm sees voluntary carbon offsets as bad; he just doesn’t see them as part of the solution to global warming.

“If you’ve gone to a lot of trouble to reduce your own emissions, and you find a way to get money to some useful projects, I don’t have a problem with that,” he says. “But I don’t think there is any difference between that and say, donating money to a major environmental organization that is working to change state and national laws.”

Muirhead, then, is doing his part on several fronts. By purchasing a hybrid car, he invested in a technology that could help change the energy sector, and his eco-conscious business approach could also serve as an example to other companies in the Charleston area. The trees Muirhead helps to plant may not help save the world as Romm says, but a tree is a tree, and they will help the environment in their own way.

What Romm reminds us, however, is that we can’t avoid global warming by writing a few checks or planting a few trees. In the end, we will have to engage the political process.

“Ultimately, individual action is great, but it’s not going to solve this problem,” he says.

For more information about Greenlight Delivery, visit www.greenlightdelivery.com.