Abstract. The impacts of climate change and changes in ozone precursor emission on ozone exposure (AOT40) of the vegetation in Europe were investigated. In addition, meteorological conditions influencing stomatal uptake of ozone were analysed to find out if climate change is likely to affect the risk for ozone damage to vegetation. Climate simulations based on the IPCC SRES A1B scenario were combined with ozone precursor emission changes from the RCP4.5 scenario and used as input to the Eulerian Chemical Transport Model MATCH from which projections of ozone concentrations were derived. Provided that the climate projections are realistic and the emission reductions of the emission scenario are undertaken, the ozone exposure of vegetation over Europe will be significantly reduced between the two time periods 1990–2009 and 2040–2059. This decline in AOT40 is larger than the reduction in average ozone concentrations. The reduction is driven by the emission reductions assumed by the RCP4.5 emission scenario, rather than changes in the climate. Higher temperatures in a future climate will result in a prolonged growing season over Europe as well as larger temperature sums during the growing season. Both the extended growing season and higher temperatures may enhance ozone uptake by plants in colder parts of Europe. The future climate suggested by the regional climate model will be dryer in terms of higher vapour pressure deficit (VPD) and lower soil moisture in southern Europe, which may reduce ozone uptake. VPD and soil moisture was not projected to change in north and north-west Europe to an extent that would influence ozone uptake by vegetation. This study shows that substantial reductions of ozone precursor emissions have the potential to strongly reduce the risk for ozone effects on vegetation, even if concurrent climate change promotes ozone formation.
Modeling of Stomatal Conductance for Estimating Ozone Uptake of Fagus crenata Under Experimentally Enhanced Free-air Ozone Exposure