摘要：Activities that remove CO2 from the atmosphere and store it in forest and agricultural ecosystems can generate CO2-offset credits that can thus substitute for CO2 emissions reduction. Are biological CO2-uptake activities competitive with CO2 offsets from reduced fossil fuel use? In this paper, it is argued that transaction costs impose a formidable obstacle to direct substitution of carbon uptake offsets for emissions reduction in trading schemes, and that separate caps should be set for emissions reduction and sink-related activities. While a tax/subsidy scheme is preferred to emissions trading for incorporating biologically-generated CO2 offsets, contracts that focus on the activity and not the amount of carbon sequestered are most likely to lead to the lowest transaction costs.
