Tourism is becoming increasingly dependent on air transport. Recent scientific work has pointed out the significant and growing contribution of air transport to greenhouse gas (GHG) emissions. Obligations to reduce GHG emissions under the Kyoto Protocol and post-Kyoto instruments might make transport more expensive or even restricted in the future. This paper examines these questions and the issues raised by the increasing number of organisations offering voluntary carbon offsetting schemes as a means of compensating for emissions of GHGs, mostly from transport, which could help to stabilise or reduce emissions. There are substantial differences between the approaches chosen by these organisations in terms of their calculation of emissions, compensation measures, price levels, company structures and evaluation processes. The paper discusses these differences and their consequences for the efficiency and credibility of voluntary carbon offsetting schemes. Within this increasingly contested area, there is general agreement that increased clarity and regulation is required.