The Impacts of Climate Change on Aircraft Noise near European Airports

The warmer air resulting from climate change reduces the lift force on a departing aircraft, potentially reducing its climb angle and causing more engine noise near the airport. Here we study this phenomenon at a selection of 30 European airports. We first formulate and verify a low-complexity model of noise propagation around airports. The model includes anisotropic noise propagation, atmospheric absorption, and multi-engine capability. We use the Airbus A320, but the method could straightforwardly be generalised to other aircraft. We refer to the model as an emulator since it mimics the more comprehensive model against which it is verified. The model is used to calculate the area enclosed by the 50 dB contour (A50), which agrees well with the same metric (using the day-evening-night sound level, Lden) from the parent model (A). Using temperature and pressure data from IPCC simulations of future climate, and using a straightforward relation between climb angle and air density, we assess how climate change could affect climb angles by mid-century (2035–2064). An optimised value of A50 is obtained by efficiently covarying (1) the engine noise at 10 m from the engines and (2) the climb angle under `historical’ conditions (1985–2014). The covariation uses Latin hypercube sampling and the optimum value of A50 differs from A by just 0.05 km2. Median values (across 10 climate models) of climb angle reduction in the future warmer climate are around 1–2%, but individual days can show values as high as 7.5%, which corresponds to an increase in A50 of 0.25 km2. When taking the local population density into account, the number of affected residents per airport increases by over 1,000 in the most densely-populated areas. We conclude that climate change could increase aircraft noise near airports in the coming decades, subjecting thousands of additional people across Europe to engine noise from departing aircraft.