Skip to main content
U.S. flag

An official website of the United States government

Publication Date
5 March 2013

Pre-industrial to end 21st Century Projections of Tropospheric Ozone from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)



The aim of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) is to better evaluate the role of atmospheric chemistry in driving climate change through both gases and aerosols. To achieve this, ACCMIP used scenarios of chemical emissions to the atmosphere, between 1850 and 2100, to study the self-consistent impact of the emissions on: the chemical state of the atmosphere; atmospheric processes; and the climate. This complements the Coupled Model Intercomparison Project (CMIP) efforts, which generally specified chemical concentrations.

This paper describes present day tropospheric ozone and its changes between 1850 and 2100 through the analysis of 15 global models (including the LLNL super-fast chemistry mechanism implemented in the CESM model) that participated in ACCMIP. The ensemble mean compares well against present day observations. Future changes were modeled using emissions and climate projections from four Representative Concentration Pathways (RCPs). Model agreement on the magnitude of the change is greatest for larger changes. Spatial patterns of ozone changes are well correlated across most models, but are notably different for models without time evolving stratospheric ozone concentrations. A unified approach to ozone budget specifications and a rigorous investigation of the factors that drive tropospheric ozone is recommended to help future studies attribute ozone changes and inter-model differences more clearly.

“Pre-Industrial To End 21St Century Projections Of Tropospheric Ozone From The Atmospheric Chemistry And Climate Model Intercomparison Project (Accmip)”. 2013. Atmospheric Chemistry And Physics, 2063-2090. doi:10.5194/acp-13-2063-2013, 2013.
Funding Program Area(s)