Plant a tree. Better yet, plant a hundred trees.

A single average tree will absorb one ton of carbon dioxide over its lifetime. Shade provided by judiciously planted trees can also reduce your air conditioning bill by 10 to 15%. The fruit provided by many trees will be a source of joy, nourishment, satisfaction, knowledge, reverence for creation, and will avoid all the chemicals and fossil fuels which are part of the production and supply chain for the fruit you would otherwise consume.

The Arbor Day Foundation has information on planting and provides trees you can plant with membership.