Comparison of registry methodologies for reporting carbon benefits for afforestation projects in the United States

Abstract

Abstract No mandatory national program currently exists to mitigate climate change in the US Consequently, voluntary programs and mandatory state-level programs are multiplying to allow users to register emission-offset activities, creating multiple often contradictory measurement and recording standards. For the land use sector we examined a hypothetical project: tree planting on rangelands in California. We apply four sets of protocols from the following registries – the California Climate Action Registry, the Chicago Climate Exchange (CCX), the Regional Greenhouse Gas Initiative and the USDOE 1605(b) program – and compare the results to the ‘actual’ net sequestration and also briefly compare them to international protocols such as the relevant Clean Development Mechanism methodology. Carbon in land use can be estimated accurately, precisely and cost-effectively, but to achieve this requires good protocols. As predicted, the consequence of applying different protocols for reportable carbon was significant. The choice of measurement pools, the handling of the baseline and the issue of uncertainty led to a baseline estimate of 0–66,690 t CO 2 -e, and final sequestered carbon totals (after 60 years) that varied between 118,044 and 312,685 t CO 2 -e—a factor of 2.5 difference. The amount reported under 1605(b) is the closest to “actual” with CCX entity reporting the most divergent.