Abstract:

Atmospheric chemistry plays a crucial role in Earth system modelling. It lies at the heart of complex interactions among air pollutants, greenhouse gases, and climate. It impacts air quality and climate forcing and offers insights into global climate change. Tropospheric ozone significantly impacts the Earth system, negatively affecting air quality, human health, and ecosystem productivity. It is also a greenhouse gas, with a radiative forcing estimated in CMIP6 of around 0.4 Wm-2.  The skill of ozone modelling has implications for estimates of radiative forcing, greenhouse gas lifetimes and secondary aerosol formation.  

My aim in this talk is to highlight recent studies on the evolution of tropospheric ozone over the historical period and into the future, including contributions to AR6 assessing tropospheric ozone.  I will also present on recent work examining the effects of elevated hydrogen levels in the atmosphere, and an exploratory study with a new UKESM Earth system model configuration, UKESM-CH4, which incorporates methane emissions, including those from online wetland sources.