ÉCLAIRE - Effects of Climate Change on Air Pollution Impacts and Response Strategies for European Ecosystems - Key Messages for Policy Makers, Year 1

The central goal of ÉCLAIRE is to assess how future climate change may alter the extent to which air pollutants have adverse effects on terrestrial ecosystems. Based on the emerging activities of the first year, it is now hypothesized that, that climate change will worsen the threat of air pollutants on Europe’s ecosystems: Climate warming may cause an increase the emissions of many trace gases, such as biogenic volatile organic compounds (BVOCs), ammonia (NH3) and the soil component of nitrogen oxides (NOx) emissions. These effects are expected to increase ground-level concentrations of NH3, NOx and ozone (O3), as well as atmospheric nitrogen deposition. Climate warming may increase the vulnerability of ecosystems towards air pollutant exposure or atmospheric deposition. Such effects may occur as a consequence of combined perturbation, as well as through specific interactions, such as between drought, O3, N and aerosol exposure. The emerging message from the first year of ÉCLAIRE is that the first of these interactions (climate-emission-concentration-deposition) is likely to be very significant. Unless decisive mitigation actions are taken, it is anticipated that ongoing climate warming will increase agricultural and other biogenic emissions, posing a challenge for national emissions ceilings and air quality objectives related to nitrogen and ozone pollution. Further evidence from the measurement and modelling activities of ÉCLAIRE is needed before any clear statements can be made regarding the second of these interactions (climate-pollution-ecosystem vulnerability). Potentially, the two effects may combine, leading to a substantial worsening of the overall air pollution threat of air pollution under future climate scenarios. The ongoing efforts of ÉCLAIRE focus on working to quantify these relationships more precisely for the different components. The findings highlights the priority for further concrete actions to mitigate air pollution emissions if a further worsening of the air pollution threat to Europe’s ecosystems is to be avoided, including on the Natura 2000 network.