Ozone Pollution

Key messages:

  • Air pollution from ozone is changing in many areas under +2°C global warming, but the amplitude of changes, which is between the range of 0 to 1.5 ppb, remains small
  • Changes due to a +2°C global warming are small compared to changes expected from air pollutant emission reduction in 2050
  • Air pollutant emission reductions are projected to continually improve air quality and reduce health issues until 2050

Why is the content of this map important?

Ozone air pollution affects human morbidity and mortality. Higher temperatures and modified weather patterns potentially affect the way ozone is formed and its concentration. It is therefore important to understand the effect of a +2°C global warming on ozone concentrations, and how related changes compare with those obtained from emission abatement policies.

Which sectors are affected by this result?

Ozone concentration affects human health and ecosystems. A higher ozone concentration leads to a higher mortality risk. High ozone concentration also affects vegetation, forests and crop yields (irrigated/rainfed). 

What is shown on the maps?

The maps show the simulated ozone concentration values for (i) the reference period and (ii) the future climate period when a +2°C global warming is reached. Ozone concentrations are in parts per billion (ppb). For the future period, changes in air pollutant emissions are also taken into account, so changes are due to both, emission and climate change. By contrast, maps showing the climate change signal for a +2°C global warming show only the effect of climate change.

Details and further information:

Using four suites of global, regional climate, air quality and health impact assessment models (CHIMERE, EMEP, MATCH, MOCAGE), we have found that a climate under a +2°C global warming modifies the near-surface atmospheric composition of air pollutants in Europe. This is due to several reasons such as changes in weather variables (temperature, precipitation, water vapour, atmospheric flow, boundary layer turbulence) and to biogenic emissions (dust, sea salt, biogenic volatile organic compounds). We have identified areas where changes are robust, where 3 of the 4 models give a change with the same sign. However the changes remain small.

Additional information:

For air pollution, four different model chains, from global to regional climate and chemistry-transport models (CTM) have been used. These CTMs are: CHIMERE, EMEP, MATCH and MOCAGE.

Two types of experiments have been conducted: (1) simulations with an air pollutant emissions reduction scenario and climate change. (2) simulations with constant air pollutant emissions and climate change.

To represent climate change simulations have been conducted for the +2°C global warming period following the RCP4.5 scenario. To represent changes in air pollutant emissions data for current (2005) and future (2050) air pollutant emissions were taken from the ECLIPSE v5 Current Legislation emissions database.

The ensemble consists of 4 simulations for each of the experiments.


Robert Vautard

Centre national de la recherche scientifique (CNRS-IPSL), France