Uncertainty estimation, quality assurance and quality control

Abstract

Carbon stocks and changes should be neither overestimated nor underestimated as far as can be judged (IPCC 2000). The uncertainty is normally high in biological and land-use sectors given the large variation in factors contributing to carbon stocks and changes. Uncertainty in the estimates that make up a carbon inventory is considered as a barrier in land-use sector, particularly in forest sector, to mitigating climate change. The uncertainty in estimated carbon stock and changes in landuse sectors is often estimated to be 25– 70% of the actual values, which has to be considered high. As a consequence, assessing the reliability and accuracy of the estimated carbon stocks and changes becomes a critical requirement, and the goal of any carbon inventory programme should be to minimize such uncertainty. It is always desirable that reported estimates of carbon stocks and changes are accompanied by estimates of uncertainty: most often, this is not so because of the complexities involved in estimating uncertainties; also, not all sources of uncertainty can be quantified. The uncertainties are in many cases so high that project managers or inventory compilers hesitate to estimate and report them.