Terra - Calculate your footprint when: Driving, Flying, Home energy use, Wedding, Events & Conferences. It shows you your footprint results and their implications as well as how carbon offsets work and green products. Sign up for weekly climate news & conservation tips.

Wikipedia - The online encyclopedia's information on carbon footprint. Includes: Defining a carbon footprint, Reducing a carbon footprint, Kyoto Protocol, carbon offsetting, and certificates, the mandatory market, the voluntary market & more.

Carbon Counter - Provides climate change solutions by purchasing high quality greenhouse gas offsets from projects that reduce greenhouse gas emissions & advancing sound offset policy.

Safe Climate - Carbon footprint calculator that allows you to determine carbon dioxide emissions from major sources: home energy consumption and transportation by car and plane. The basic instructions below are augmented by help on pop-up screens on the following pages.

Nature - Use The Nature Conservancy's carbon footprint calculator to measure your impact on our climate. Learn about climate change and global warming, carbon offset program & climate-saving tips.

Carbon Footprint - Is a measure of the impact our activities have on the environment, and in particular climate change. The sites Mission is to educate and inform how we can all make the right choices both at home and at work. Has a carbon footprint calculator, information on climate change, carbon offsetting & more.

Conservation - A step-by-step interactive guide to reducing your carbon footprint. It will give you quick offsets, tips on living green, you can measure your Eco-Footprint and much more.

Be Green Now - Empowers you to take an active role in neutralizing your carbon emissions and reducing your impact on global warming. Simply follow the tips to begin decreasing the energy you use each day, and offset the rest of your carbon-emitting energy use through our easy-to-use carbon calculator & carbon offsets.

Carbon Aided - Helps business, individuals, charities and NGOs to reduce their impact on climate change. Helping those we work with to: understand and reduce their carbon footprint use robust carbon offsets to neutralize carbon emissions that cannot be avoided or reduced.