Carbon offsets are tradable “rights” or certificates linked to activities that lower the amount of carbon dioxide (CO2) in the atmosphere. By buying these certificates, a person or group can fund projects that fight climate change, instead of taking actions to lower their own carbon emissions. In this way, the certificates “offset” the buyer’s CO2 emissions with an equal amount of CO2 reductions somewhere else.
Although carbon offsets have appealing benefits, it is important to keep in mind the challenges and costs of using them, including the difficulty of verifying their environmental benefits. Several studies of offset markets have found evidence of “over-crediting,” or selling offsets that promise more emissions reductions than they actually achieve. Another concern is whether companies and countries are using carbon offsets as a “get out of jail free card” to avoid lowering their own carbon emissions. Nonetheless, if used appropriately, offsets can be a useful tool in the fight against global warming.