Purging Carbon Dioxide from the air may not be so easy

I had prepared for an interview, not an interrogation. But before I could pose my first question to environmentalist Ian Lumley of the National Trust for Ireland, he had a few for me.

"So, Condé Nast Traveler would be a very large travel magazine, would it?"

"One of the largest."

"The kind that encourages its readers to fly to the Maldives?"

"Well, we do sometimes run stories on the Maldives."

"Jets emit carbon dioxide. Carbon dioxide causes global warming. You're a big part of the problem."

Talk about swift justice. In less time than it takes most people to finish their how-do-you-dos, I'd been tried and convicted of crimes against the environment. The verdict stung all the more because for 20 years Condé Nast Traveler has not only reported on green causes but actively supported them with its annual $20,000 Environmental Award.

Still, I couldn't help wondering if Lumley had a point. Jet engines produce about 3.5 percent of the world's human-generated carbon dioxide (CO2), the greenhouse gas most responsible for climate change. This might not sound like much—especially when measured against auto emissions' 15 percent—but the CO2 generated by air travel has been increasing faster than any other source, and is expected to double in the next 25 years. Even worse, scientists say that releasing greenhouse gases at high altitudes is three times more damaging than discharging them on the ground. In May, the Intergovernmental Panel on Climate Change announced that reducing CO2 emissions by half over the next 40 years may allow us to avert environmental disaster. That news, combined with rising seas and melting ice caps, makes willfully boosting our output of greenhouse gases tantamount to sticking our heads in the sand—or in this case, in an oven.

Which is why companies that promise to undo the environmental damage we cause when we fly are springing up like so many green weeds. In exchange for a small fee, these outfits say they will negate the emissions produced by your flight by contributing to clean-energy projects, such as wind or solar power, or by planting trees, which cleanse CO2 from the air—an arrangement known as carbon offset. The cost ranges from about $10 to $30 per ton of CO2—roughly the amount attributable to one passenger flying round-trip between New York and Los Angeles.

There's an alchemical appeal to the idea that we can pay to keep our atmosphere clean—and our consciences clear—while traveling as we please. But in the real world, the one that's getting hotter by the moment, it's not so simple. It can take 70 years for a single tree to filter the amount of CO2 produced by just one flight. Unfortunately, the polar bears probably can't wait that long. And when trees decompose, they release back into the environment all of the carbon they've absorbed during their lifetime, so this is a temporary solution at best. In fact, until someone creates a machine to vacuum CO2 out of the air, we cannot pay to instantly undo the damage our flights cause any more than we can unpick a flower. Leading people to believe otherwise is not only irresponsible but dangerous: It's a lie that falsely absolves us of responsibility.