US nonprofit organization with great projects and a low price per ton of carbon offset. Funds reforestation in Louisiana and Nicaraguan Rain Forest: wind, solar and methane power plants across the United States. Flight calculator is midway down the first page at this web site

Wind farms in Oklahoma, Nebraska, Minnesota, and California are supported by this US carbon credit firm, as well as methane power plants in Kentucky and North Carolina.

UK-based firm offering Certified Emission Reductions (CERs) and Verified Emission Reductions (VERs) to all standards including Gold Standard and VCS. Does not develop its own projects, but only invests in those of others which have been audited and certified.

Another UK-based firm, this one offering forestation projects in Europe and energy efficiency projects in Africa. Also offers an unique option, EU emissions credits which may be purchased and retired, making them unavailable to polluters.

Renewable energy projects (wind, solar, methane gas) on small family farms and Native American reservations in the US are featured on this site.

Australian firm funding a wind farm in India, an energy efficiency project in South Africa & methane gas power plants in Mexico, Thailand and South Africa.

Australian firm funding Gold Standard projects in India and China. Donates 5% of net sales to the World Wildlife Fund. Projects audited by Australian government, Ernst &Young.

While the Nature Conservancy doesn’t offer a per flight carbon calculator they do calculate your total carbon footprint and can provide offsets for this amount. With an impeccable reputation and an aggressive program of purchasing land for preservation this organization is a perfect choice for travelers who want to be sure their carbon offset investment is well spent.