3. Flow of Calculations for Quantifying Net GHG Reductions and Removals

Calculation of offset credits requires a chain of measurements, estimates, and modeling exercises. It requires measuring what did happen, estimating what likely happened, and modeling what might have happened. It requires dealing with uncertainty and risk. It differs importantly from conventional inventory processes in that it deals with some things that can be counted and some that cannot. And the California offset program deals with these calculations in a conservative way so that errors are on the side that credits are unlikely to be given for offsets not produced but there are likely to be offsets created for which credit is not given. This section describes the core details of what goes into the calculation process and indicates some of the ancillary data that are required. It does not discuss the physical measurements required to document the amount of carbon actually stored on site in the forest ecosystem as these have been widely discussed and the California requirements are consistent with popularly accepted procedures.