To make up for some of the environmental damage done by when you fly, consider making the trip carbon neutral. This involves calculating how much your flight generates in greenhouse gas emissions and buying a certificate or share in a project that aims to reduce emissions by that same amount.

Many of these carbon offset programs or projects involve tree planting because trees have a huge capacity to absorb carbon from the atmosphere. They’re not the only choices, however; others involve everything from supporting solar and wind power to replacing fossil fuel–burning stoves in developing countries with more sustainable energy sources. There also are programs in which you pay for energy-efficient appliances or energy conservation schemes in developing countries.

Making your flight carbon neutral is certainly a positive step, but there’s a limit to how effective carbon offsetting programs can be; after all, there’s a finite amount of land on which to plant trees. It’s best to include the purchase of carbon offsets as one part of a personal green living strategy that includes reducing flights, too, rather than as a complete solution.

A growing number of airlines and other travel businesses are providing one-stop shopping for carbon offsets, making it very easy to purchase them. You can simply opt in at the time you purchase your ticket. (Some outfits even include the carbon offset in the ticket purchase price.) Other organizations are making independent carbon offset programs available, which is an excellent option if you have specific ideas about what you’d like to support.

When you’re choosing a carbon offset provider, don’t be afraid to ask questions or research the program’s background thoroughly.

Consider selecting a nonprofit organization to ensure that your money and support go to carbon offsetting programs rather than contribute to a business’s profitability. Also make sure that you’re supporting a program that wouldn’t have been possible without the carbon offset scheme. Otherwise, you’re not actually contributing to an additional program; you’re simply paying for something that was going to happen anyway. To make your purchase go further, look for programs that actually reduce the amount of carbon that’s produced in the first place rather than simply trying to take out what’s in the atmosphere. For example, some programs are helping to make charcoal or wood-burning cookstoves in developing nations more efficient — this not only reduces the carbon that the stoves release but also helps to conserve a precious natural resource.

Sustainable Travel International offers a selection of carbon offset programs that independent experts have examined to make sure they meet criteria such as these. Sustainable Travel calculates carbon offsets for your flights; you simply enter your departure and destination airport, and it lets you know what the carbon dioxide emissions related to that flight will be and how much it will cost to offset them. For example, a one-way flight between New York and Paris produces 1.3 tons of carbon dioxide, which costs $20 to offset.