This paper describes a system whereby carbon emission credits would be rented, rather than sold, when carbon is sequestered but permanence of sequestration is either not certain or not desired. Such a system recognizes that stocks and flows can be alternative descriptions of the same phenomenon, and that a stock need not exist in perpetuity to have an equivalent flow. Hence, temporary carbon offset credits can be traded in markets similar to those used for carbon emissions credits. The author lays out how this approach removes the necessity of using the awkward ton-year approach that has sometimes been suggested.
