Aviation and climate change: a scientific perspective

Lee, DS and Fahey, D (2016) Aviation and climate change: a scientific perspective. Carbon and Climate Law Review, 10 (2). pp. 97-104. ISSN 1864-9904

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Abstract

Global aviation operations combust fossil fuel and emit gases and aerosol to the atmosphere, altering its composition. In addition, aviation produces linear and spreading contrails that increase global cloudiness, and modify natural background clouds. Atmospheric composition and cloudiness largely control the balance in Earth’s atmosphere between incoming radiation from the Sun and outgoing radiation from the atmosphere and surface. Any imbalance caused by human activities can lead to long-term changes in climate. At present, aviation emissions and cloudiness do contribute to an imbalance (i.e., net positive radiative forcing) in Earth’s climate system that contributes to surface warming and other changes. The magnitude of the imbalance is a few percent of that caused by all human activities since pre-industrial times. Principal emissions that arise from aviation fuel combustion are carbon dioxide (CO2), nitrogen oxides (NOx), hydrocarbons (HC), sulfur species (SOx), black carbon particles (BC), and water vapor (H2O). This paper addresses the scientific understanding of the processes that connect aviation emissions and aviation impacts on cloudiness to climate change, and highlights important remaining uncertainties. Scientific understanding helps guide choices concerning how climate change from aviation operations can be reduced in coming decades.