The social value of offsets.

It is unclear how much carbon should be stored in temporary and risky offsets to compensate one ton of CO emissions. Here we cast the social value of an offset (SVO), measured in terms of economic damages avoided, as a well-defined fraction of the social cost of carbon reflecting offset duration, and risks of non-additionality and failure. The SVO reflects the value of temporary storage, and overcomes shortcomings in the climate science and economics of previous contributions.