What Is a Carbon Offset?

Via the David Sizuki Foundation this article about carbon offsets:

A “carbon offset” is an emission reduction credit from another organization’s project that results in less carbon dioxide or other greenhouse gases in the atmosphere than would otherwise occur. Carbon offsets are typically measured in tons of CO2-equivalents, and are bought and sold through a number of international brokers, retailers and trading platforms.

The article goes on to describe the merits of different types of carbon offsets based on how permanent the projects are they invest in and how well they reduce the world's dependence on fossil fuels. It concludes with this advice:

Regardless of the offset type one chooses, it is advisable to purchase offsets that have been verified by an independent third party. Some NGOs and private offsets providers arrange third party verification for the offsets they offer, although the criteria and standards that are applied can vary.