What then must we do?

Mohandas Gandhi exhorted those interested in social change to "be the change you want to see in the world." His injunction is widely quoted because it reminds us that systemic change can be initiated by the actions of one committed individual. It implicitly cautions us not to wait for our political leaders to remedy injustice.

Gandhi's message, a touchstone for generations of activists, seems to have fallen out of use. When it comes to addressing the singular threat of global warming, few people, even among those who consider themselves environmentalists, fully identify with the solutions that could help us avert the catastrophic symptoms of global warming.

Many of us who consider ourselves "green" dutifully replaced our incandescent light bulbs with compact fluorescents, replaced unnecessary car trips with walking and buy locally-grown food whenever possible. But in most cases, we also travel on airplanes with impunity. In this act, our carbon footprint, which most of the time we so carefully tend, grows enormous.

It turns out that air travel, one of the shiniest emblems of modern cosmopolitanism, is a very dirty habit. Calculate your carbon footprint at any of a number of internet sites, and you'll see that even a couple of airplane trips per year can lead to more carbon emissions than a whole year's worth of driving (BP's carbon footprint calculator is a good place to start).

Princeton bankrolls international travel for undergraduates on the premise that there are many things about the world that cannot be learned in Firestone Library or Fine Hall. The educational value of such exploration is surely very high, but so is the cost to future generations and the masses of poor people around the world most vulnerable to the changes wrought by global climate change. If taking a plane from Newark to Harare, Zimbabwe places me on a causal chain from carbon emissions to rising sea levels which very well might lead to the displacement of millions of marsh-dwelling Bangladeshis, is it really worth it after all? There may be virtue in self-identifying as world travelers and global citizens but there is none in what it takes to make us these things.

Of course, a truly green lifestyle comprises more than a refusal to step on an airplane. Barclay Satterfield of Greening Princeton reminded me that small improvements, such as upgrading to energy efficient appliances and light bulbs, really do add up if we make a lot of them. Checking off these small things is something that everyone can do, but none of us can make a real claim to environmentalism if we make the eco-friendly choices when it suits us but refuse to give up the dirtiest privilege of all. If we who call ourselves environmentalists are comfortable with the sacrifices that most of us now make — sacrifices which are easier to make than giving up air travel — then we should get used to the idea that the worst predictions about climate change will likely come to pass and that we did not do everything we could to stop them.

I won't pretend not to be distressed at the thought of giving up expeditions to other continents. But I have the feeling that the end of our globetrotting days might be the beginning of something better entirely. If we give up air travel for pleasure, we can take up the kind of lives in which we don't need it nearly so much. We can build communities and find work from which we do not need to take vacations to other hemispheres. Ultimately, the rejection of air travel is an expression of hope, a belief that we can save this world if only we make the necessary sacrifices. Thomas Bohnett is a Wilson School major from Princeton Junction. He can be reached at tbohnett@princeton.edu.