European atmosphere in 2050, a regional air quality and climate perspective under CMIP5 scenarios

Abstract

To quantify changes in air pollution in Europe at the 2050 horizon, we designed a comprehensive modelling system that captures the external factors considered to be most relevant and relies on up-to-date and consistent sets of air pollution and climate policy scenarios. Global and regional climate as well as global chemistry simulations are based on the recent Representative Concentrations Pathways (RCP) produced for the Fifth Assessment Report (AR5) of IPCC whereas regional air quality modelling is based on the updated emissions scenarios produced in the framework of the Global Energy Assessment. We explored two diverse scenarios: a reference scenario where climate policies are absent and a mitigation scenario which limits global temperature rise to within 2 &deg;C by the end of this century. <br><br> This first assessment of projected air quality and climate at the regional scale based on CMIP5 (5th Climate Model Intercomparison Project) climate simulations is in line with the existing literature using CMIP3. The discrepancy between air quality simulations obtained with a climate model or with meteorological reanalyses is pointed out. Sensitivity simulations show that the main factor driving future air quality projections is air pollutant emissions, rather than climate change or long range transport. Whereas the well documented "climate penalty" bearing upon ozone over Europe is confirmed, other features appear less robust compared to the literature: such as the impact of climate on PM_2.5. The quantitative disentangling of each contributing factor shows that the magnitude of the ozone climate penalty has been overstated in the past while on the contrary the contribution of the global ozone burden is overlooked in the literature

Moving towards ambitious climate policies: Monetised health benefits from improved air quality could offset mitigation costs in Europe

“…There is a slight increase (1%) between 2005 and 2050 in the reference scenario which is explained by a joint effect of global warming and long-range transport of pollution from outside Europe (Colette et al, 2013a) which counterbalances the effects of the European atmospheric policy (Fig. 1b).…”

“…Thus these scenarios represent the most up-to date basis for analysing air pollution related issues, particularly at a regional scale. These scenarios were used before in Rao et al (2012) or Colette et al (2012Colette et al ( , 2013a, although these studies were limited to air quality and/or health impacts and did not include any cost-benefit analysis.…”

“…The climate and air quality modelling chain is only briefly summarised here, and the reader is referred to Colette et al (2013a) for further details. For the assessment of European air quality we use a set of scenarios at the 2050 horizon, with consistent estimates for greenhouse gas and air pollutant emissions at global and regional scales: emission scenarios for Europe developed under the Global Energy Assessment (GEA 3 ) in combination with global chemistry simulations and climate fields from the air pollution cost savings (77%) in Europe.…”

Impact of a future H 2 transportation on atmospheric pollution in Europe

“…The possible effects of climate change on air quality are complex: for example, it is generally predicted that a warmer climate could lead to a slight increase in pollution levels, while an increase in precipitation can lead to pollution decrease (e.g. Colette et al, 2013;Fiore et al, 2012;Isaksen et al, 2009;Jacob and Winner, 2009). Model studies have shown that the climate impact on future air quality is in general much smaller than the impact of change in emissions.…”

Projections of summertime ozone concentration over East Asia under multiple IPCC SRES emission scenarios

“…Tagaris et al (2007) estimated that the summertime DM8H ozone levels over the United States could decrease by 20% (regionally varying from À11% to À28%) by the combined effects of climate change and emission reductions. The projection of air quality and climate at the regional scale over Europe in 2050 was performed under 5th Coupled Model Intercomparison Project (CMIP5), and the main factor that drives future air quality projections was found to be air pollutant emissions rather than climate change or intercontinental transport of pollution (Colette et al, 2013).…”