ABSTRACT
The rapid growth in emissions from the aviation industry presents a number of challenges if we are to avoid climate change greater than 2°C above pre-industrial levels. As discussed elsewhere in this volume, absolute volumes of emissions from aviation will be significant under constrained, cumulative emissions budgets and opportunities for technological improvements are limited. Rather than internal abatement, carbon trading and voluntary carbon offsetting have been presented as alternative mitigation strategies and aroused much controversy in the process. This chapter focuses on voluntary carbon offsetting which in its simplest terms is an economic exchange between two participants: a transaction with money moving in one direction and emissions rights, quantified in tonnes of CO2 equivalent (tCO2-eq), in the other. The rationale is that rather than reduce emissions at source, a polluter may pay for reductions to be made elsewhere, usually at lower cost, on the assumption that both the initial party’s emissions and the secondary party’s reductions can be calculated and made equivalent. An example might be an airline passenger flying New York–Amsterdam paying a contribution towards the installation of a new hydroelectric dam in China that displaces coal-generated electricity from the local grid. Tree-planting schemes that are intended to sequester CO2 from the atmosphere and store it biologically are also commonly developed.
