Carbon offsetting is the practice of purchasing or building carbon sinks which match or exceed an individual or corporation's carbon dioxide emmissions. Carbon offset activities could include buying stocks in a "green" power company, using solar power, and the like. The goal is to keep an individual or corporation's net carbon emissions at zero, in order to stave off the theoretical warming due to the greenhouse effect.
Critics point out that, while carbon dioxide has the largest volume of controllable contributions to theorized atmospheric warming, it has the lowest effect on a per molecule basis of any of the greenhouse gases.[Citation Needed]
It is important to note that, while planting trees is perceived to be a "green" activity, a simple balance over the life and death of the tree will show that this activity does not actually decrease carbon dioxide in the atmosphere. While carbon is consumed by the tree during growth, the exact same amount of carbon is produced during decomposition. The net carbon gain, therefore, is zero over the entire life cycle of the tree.[Citation Needed]
It is estimated that in the first three quarters of 2006, about 130 million dollars were spent offsetting the carbon emissions of companies and individuals, a 300 per cent increase from 2005.  The companies marketing the carbon offset credits are unregulated and there is a lack transparency of where the money for offsets is spent.[Citation Needed]
- Carbon sequestration - the act of preventing carbon dioxide from a process from mixing with the atmosphere