Air quality and climate - WCSSP case study
Research led by the Met Office as part of the CSSP China project, has used a global Earth system model to investigate the impact of future changes in air pollutants on air quality and the climate.
Poor air quality is one of the largest environmental risks to public health. The World Health Organisation estimates that exposure to outdoor air pollutants are associated with 4 million premature deaths every year around the world. Research led by the Met Office, as part of the Climate Science for Service Parternership (CSSP) China project, is investigating the impact of future changes in air pollutants on air quality and the climate.
The links between air quality and climate
Air pollution is linked to the Earth’s climate. Several of the drivers of air pollution, such as the combustion of fossil fuels, are also sources of greenhouse gas emissions. Some pollutants can also influence the climate, for example ozone traps heat in the lower atmosphere, adding to the already enhanced, human-induced greenhouse effect. In contrast, tiny air pollution particles which are also known as aerosols, can have a cooling effect on the climate by reflecting sunlight back out to space.
Through the CSSP China project, researchers are studying how changes in atmospheric compounds could influence air quality and climate. The researchers focused on compounds such as methane and ozone which are known for being short-lived because they are produced and removed in the atmosphere over much shorter timescales when compared to the long-lived greenhouse gases such as carbon dioxide.
Using a global earth system model, the researchers compared a selection of future mitigation scenarios to understand how changes in these compounds influenced the rate of climate warming and air quality.
“We found that simultaneously reducing concentrations of methane and aerosols would lead to the largest benefit to both future climate, air quality and human health, particularly across Asia”, Dr Steven Turnock, Met Office Senior Scientist.
However, the relationship between these atmospheric pollutants and climate and air quality is complex. The researchers found that if only aerosols are reduced, then this leads to a benefit to air quality but could result in detrimental impacts on climate. The results of the study provide useful insight which could be used to inform future policy decisions and mitigation planning.
Other air quality research part funded by CSSP China has impacted policy reports including the WMO Air Quality and Climate Bulletin and the European Commission’s report on Global trends of methane emissions and their impacts on ozone concentrations.
“Our findings highlight that reducing different short-lived atmospheric pollutants can have different impacts, particularly regionally, and that measures to benefit both future climate, air quality and health need to be carefully designed”, commented Steven.