Travel Column: Offsetting Air Travel's Greenhouse Impact

Jonathan Tourtellot and Nandita Khanna
National Geographic Traveler
August 9, 2004
Updated from National Geographic Traveler magazine's
TravelWatch and Smart Traveler sections

Global warming is threatening travel. What's more, travelers themselves are contributing to it. The good news is, they can do something about it.

With another heat wave in Europe, melting glaciers, shrinking Antarctic ice shelves, and revelations that Alaska's permafrost is turning to mush, it's clear that global warming is changing destinations around the world—especially high latitudes, high altitudes, and low seacoasts.

Some ski resorts, noting that heat is incompatible with their basic product, have started reducing their greenhouse gas output by converting to clean solar and wind power. Skiers who would like some day to see their grandchildren enjoy the slopes would do well to favor such resorts.

More significant, most scientists agree that the seas are rising. Low-lying destinations like Venice and the resort-rich Maldive atolls are already building protective dikes.

The tiny Pacific-island nation of Tuvalu has become something of a poster child for sea-level rise, but in fact the effects are far more widespread, as high-water marks slowly advance on the resorts and vacation homes along any low-profile coast.

As it happens, air travelers especially can actually do something about the warming. Say you've just flown the U.S. coast to coast. Each passenger, including you, has just accounted for an additional ton of carbon dioxide and other greenhouse gases per person pumped into the atmosphere.

That's twice as bad as driving the trip in a gas-guzzling SUV. Alone. (Trains, by contrast, emit only a third as much.)

Carbon Offset

"Carbon offset" provides a solution. To make up for the carbon dioxide your trip creates, you can support programs for planting trees, which consume CO2, or energy-saving projects that reduce CO2 emissions elsewhere.

Two years ago Susan Peterson, for instance, began purchasing wind energy certificates through the local utility provider for her Boulder, Colorado, home. Each certificate represents a unit of electricity added to the regional power grid by a wind farm instead of by burning fossil fuels.

In addition to mitigating her domestic energy use, she also now buys U.S. $20 worth of wind certificates monthly to counterbalance the carbon dioxide produced by her frequent air travel.

"Most people want to do something for the environment; they just don't always know what to do," said the 48-year-old sales consultant. "This is small, doesn't cost a lot, and has an impact."

Others share Peterson's point of view. A recent report by the Center for Resource Solutions indicates that certificate sales exceeded 1.9 million megawatt-hours in 2002, doubling from the previous year.

Still, offsetting greenhouse gases from jet travel remains purely voluntary.

Air travel is expected to double in 15 years and already accounts for 3.5 percent of human-generated greenhouse gas. Nor will better engineering be likely to help.

According to Jamie Sweeting of the Center for Environmental Leadership in Business, airliners (unlike cars) seem to be about as fuel-efficient as the state of the art allows. Offset looks like the best solution for long-distance travel.

But industry and government can't expect conscientious passengers alone to bear the burden of taking countermeasures. By agreement, they should build the small cost of offset into all airfares. It's worth it.

With carbon offset, we can fly guilt free. Except when it's a short trip and there's a good train available.

What You Can Do

Purchase wind certificates.
Organizations such as WindCurrent (, NativeEnergy (, and Renewable Choice Energy (www.renewablechoice) allow customers to purchase certificates, sometimes known as green tags to offset emissions caused by automobile or air travel. Some of these sites have CO2 calculators that estimate your impact in tons.

Plant trees. Forests take CO2 out of the atmosphere and lock it away in wood, where it stays until the wood rots or burns. Maryland-based Trees for the Future ( offers a "Cool Car Certificate" that plants 300 trees (the estimated amount of trees it will take to offset one vehicle's emissions in a lifetime) for $30.

You can offset air travel through its "Trees for Travel" program ($1 will offset a round-trip domestic flight, $3 an international one).

The United Kingdom-based Future Forests ( plants trees in more than 80 forests in the U.K., Mexico, India, and the U.S. A global flight calculator determines how many trees you need to plant to offset a flight—two trees, for example, for a New York-to-London round trip, or $30—as a part of the CarbonNeutral flight program.

Support other offset programs. U.K.-based Climate Care ( provides a mix of offset strategies with programs that save energy, that encourage clean energy, and that remove CO2 (sample donation: $11 to offset a New York-to-L.A. round trip).

The Better World Club (, an eco-oriented auto club, offers members who book plane tickets through its in-house travel agency free carbon offsets on two domestic and one international flight each year. Nonmembers worldwide can purchase offsets—$11 for a domestic flight and $22 for an international flight.

Drive a hybrid car. With a fleet upward of 250 cars, EV Rental Cars (, offers eco-friendly cars at eight metropolitan locations including, Los Angeles, Phoenix, San Diego, and Washington, D.C., through its partnership with Budget (

Enterprise Rent-a-Car ( followed suit in May and acquired some 2,700 Toyota Prius models for rent in select U.S. cities.

Switch to low-energy, compact fluorescent light bulbs. Bright and warm like conventional bulbs, they last ten times longer, use a third of the power, and prevent release of half a ton of CO2 by the U.S. power grid. Though pricey to buy, each bulb will still save you at least $30 on your electric bill over its long lifespan. Six bulbs will offset your continental round trip. Ten may well pay you for it.

For more greenhouse-gas news, scroll down.

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