Carbon Offsets

How does travel impact global warming?

Every time you drive or fly, you emit carbon, which contributes to global warming. Worldwide, airline travel contributes to roughly 2% of carbon emissions. While this may not seem like much, each flight you take does have an impact. For example, a flight from New York to London emits approximately 2.8 tons. Compare that to the average American's total annual emissions of about 20 tons, and you can see that flying is carbon-intensive. (Compare it to the average Nepali's annual emissions of 0.1 tons, and the picture becomes even more troubling.)

Where does your money go and how does it "offset" your travel?

There are two sides to the carbon offset equation: On one side, you calculate how much carbon a certain activity emits. Let's use, as an example, a flight from San Francisco to Paris. Your personal share of carbon emissions for that flight equals approximately 4.5 tons.

On the other side of the equation, a hypothetical carbon offset company has identified a potential wind energy project that needs additional funding to be built. They calculate how much wind energy this project will generate over its lifetime and assign a dollar figure to each kilowatt-hour based on the cost of generating it. They reason that every kilowatt-hour of clean energy generated by its project replaces a kilowatt-hour that would have otherwise been generated by a "dirty" energy source, e.g., a coal-fired power plant.

The idea of "offsetting" is that your monetary contribution is responsible for a share of the wind project that equals the amount of carbon you've emitted by your activity. In the case of our flight to Paris, you would pay $60 to help fund the building of a wind farm.

This model has some obvious pitfalls: First of all, the term "offset" might imply that you are "neutralizing" the impact of your travel, and thus it has no impact. This is not the case. Once you have emitted carbon, it is released into the atmosphere and you can't "take it back." What offsetting does is help reduce carbon emissions elsewhere.

Next, the offset model attempts to neatly compress a very complex set of calculations into a tidy equation, when in actuality, it relies on a series of assumptions and estimates. For example, the carbon offset company would have to estimate how many passengers are on an average flight and make predictions as to how much energy a given turbine will produce over its lifetime. In addition, there is a good deal of debate among global warming experts about just how much impact flying has on global warming. So it's important to keep in mind that the numbers generated by a carbon calculator are estimates.

Finally, the relationship between your travel choices and carbon emissions is of course not as cut-and-dry as is assumed by the offset model. After all, if you don't get on that flight to Paris, the plane will still fly. The idea of course is that cumulatively, the less we all fly, the less demand there will be for air travel, and the less additional supply the airlines will deliver. On the other side of the equation, the more market demand we can create for clean energy, the better.

Why doesn't Sierra Club Outings offer "carbon-neutral" trips?

If you've been shopping around for travel, you know that many of our competitors offer so-called "carbon-neutral" trips. As an environmental organization, why don't we? Quite frankly, we think that calling travel "carbon-neutral" is misleading. It's important to remember that offsetting your emissions does not "undo" them. Rather, it reduces carbon emissions elsewhere to "offset" what you have emitted.

Sure, we could just raise our trip prices, take care of the offset payment for you, and call ourselves carbon-neutral. In fact, we'd probably sell more trips and make more money that way. Problem is, we'd be missing a valuable opportunity to educate you about global warming and the impact that your personal choices have. We'd rather let you calculate your emissions and decide how you can reduce your overall carbon footprint by reducing travel or making changes in other aspects of your life.

Isn't this just "greenwashing"?

You've read it in the news: Celebrities are flying all over the globe in private jets, then assuaging their guilty consciences by buying offsets. Airlines and utilities are going "carbon-neutral." Some offset vendors are making obscene profits and contributing less than 20% of revenues to projects. So are carbon offsets nothing but "greenwash"?

Yes, there are offset providers out there who are not delivering on their promises. This is still a relatively new industry, and while there are several organizations that are trying to establish standards for offset quality, the industry is currently largely unregulated. So unless you really look closely at projects and ask lots of difficult questions, it's hard to tell whether the money you spend is actually doing any good.

We are also highly skeptical of anyone who claims that carbon-offsets are a "silver bullet" that will solve the global warming crisis. This simply is not true. As consumers, we will need to make difficult choices in the coming years to reduce our personal carbon footprint. We will also have to pressure our politicians to vote for real, far-reaching legislation that will reduce our dependence on "dirty" energy. Carbon offsets are merely a small part of the solution.

What else can you do to fight global warming?

The Sierra Club is working to reduce carbon emissions by 2 percent a year for the next 43 years, which scientists tell us we all must do in order to curb the worst impacts of global warming. Every individual and institution needs to decide how they will reduce their emissions. For some, this may mean purchasing a more fuel efficient car, for some it may mean canceling some travel, for others it may mean investing in better insulation or more efficient appliances. We are doing our part in the Outings program by reducing on-trip transportation and insisting on sustainable practices by the local establishments we frequent.

While your personal lifestyle choices are important, they need to be coupled with far-reaching political change on a local, national, and international level. Learn more about what we're doing and how you can help.

Please visit our frequently asked questions and trip planning pages for other useful information for planning your trip.