ABSTRACT
This chapter provides an overview of the sector's environmental impacts, and discusses air travel's contribution to emissions of greenhouse gases and policy responses to address the situation. The importance of greenhouse gases has been recognised for more than a century, with Arrhenius publishing a first calculation of global warming related to a potential doubling of atmospheric concentrations of CO2 from anthropogenic sources. The contribution of human activities to climate change is measured on the basis of the so-called basket of six, including the long-lived greenhouse gases carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride. The chapter discusses various environmental aspects of aviation, and their current importance. Many of the issues that became increasingly important with the growth of air travel, including noise, land use needs for airport construction and expansion, or climate change, continue to be of relevance.
