Assessing the impact of aviation on climate

Abstract

We present an assessment of the marginal climate impacts of new aviation activities. We use impulse response functions derived from carbon-cycle and atmospheric models to estimate changes in surface temperature for various aviation impacts (CO 2 , NO X on methane, NO x on ozone, sulfates, soot, and contrails/induced cirrus). We use different damage functions and discount rates to explore health, welfare and ecological costs for a range of assumptions and scenarios. Since uncertainty is high regarding many aviation effects, we explicitly capture some uncertainty by representing several model parameters as probabilistic distributions. The uncertainties are then propagated using Monte Carlo analysis to derive estimates for the impact of these uncertainties on the marginal future climate impacts. Our goal is to provide a framework that will communicate the potential impacts of aviation on climate change under different scenarios and assumptions, and that will allow decision-makers to compare these potential impacts to other aviation environmental impacts. We present results to describe the influence of parametric uncertainties, scenarios, and assumptions for valuation on the expected marginal future costs of aviation impacts. Estimates of the change in global average surface temperature due to aviation are most sensitive to changes in climate sensitivity, the radiative forcing attributed to short-lived effects (in particular those related to contrails and aviation-induced cirrus), and the choice of emissions scenario. Estimates of marginal future costs of aviation are most sensitive to assumptions regarding the discount rate, followed by assumptions regarding climate sensitivity, and the choice of emissions scenario.