Manipulating biotic carbon sources and sinks for climate change mitigation: Can science keep up with practice?

The potential for natural C sinks to be manipulated by human means to mitigate climate change has been discussed in the environmental literature for more than a decade. There now appears to be little doubt that changes in global land-use and land management practices could significantly slow the accumulation of CO₂ in the atmosphere. As a result, some forward-thinking companies and governmental bodies are acting now upon the biotic mitigation literature by developing actual mitigation projects. It is now national policy in the United States to encourage such activities. The future of C offsets, however, is unclear, due in large measure to lagging scientific knowledge. Large-scale private action likely will await regulatory signals that action will be accepted as a legitimate mitigation measure, perhaps providing retroactive regulatory credit, a source of tradeable emission entitlements, or credit against yet-to-be-established C taxes. The practical potential of most biotic mitigation approaches is unknown, and the entire concept remains subject to political challenge domestically and abroad. The ability to predict C benefits of individual mitigation projects is often tenuous and subject to debate. To allow expansion of C offset practices as quickly as possible, and hopefully to fund projects with many ancillary environmental and economic benefits, policymakers and project developers desperately need physical and social science data to be provided in a useable form.