The assessment of greenhouse gases (GHGs) emitted to and removed from the atmosphere is high on both political and scientific agendas internationally. As increasing international concern and cooperation aim at policy-oriented solutions to the climate change problem, several issues have begun to arise regarding verification and compliance under both proposed and legislated schemes meant to reduce the human-induced global climate impact. The approaches to addressing uncertainty discussed in this volume attempt to improve national inventories or to provide a basis for the standardization of inventory estimates to enable comparison of emissions and emission changes across countries. Several authors use detailed uncertainty analyses to enforce the current structure of the emissions trading system while others attempt to internalize high levels of uncertainty by tailoring the emissions trading market rules. In all approaches, uncertainty analysis is regarded as a key component of national GHG inventory analyses. Topics of interest include: -national greenhouse gas emission inventories -bottom-up versus top-down emission analyses -signal detection and analysis techniques -verification and compliance issues -role of uncertainty in emissions trading schemes -compliance and emissions trading under the Kyoto Protocol. Assessment of uncertainty can help improve inventories and manage risk. Through recognizing the importance of identifying and quantifying uncertainties, great strides can be made in the process of Accounting for Climate Change.