This is an incomplete post salvaged from the internet archive.

-by John

This is a common question, and it begs varied responses because the issue is highly contextual. The idea generally revolves around the fact that carbon dioxide and the other Green House Gasses (GHG) persist and spread throughout our atmosphere for at least 100 years. Because their presence is diffuse, the location of GHG emission is not important. Net quantity is the issue, and the theory of offsetting essentially posits that by funding emission reductions somewhere else, one counters their own direct or indirect emissions arising from sources such as cars or electricity. This manifests itself in many ways, and there does not appear to be consistency in the metrics. Offsetting organizations offer a diverse portfolio, from wind power, to energy efficient development, to bovine methane power, to forest sinks.