Abstract:
Two-way feedbacks between atmospheric composition changes and climate dynamics have gained increasing attention due to its critical role in weather and climate prediction. In this talk, I will provide a broad overview of the field’s development and highlight where chemistry-climate interactions are considered most significant. I will present a range of examples based on advanced modeling and newly developed observational climate data records to illustrate chemistry–climate coupling across timescales from S2S weather patterns to long-term climate trends. These include the influence of dynamical processes and abrupt events—such as sudden stratospheric warmings and the Hunga Tonga eruption—on stratospheric composition anomalies and their feedbacks on meteorological and climate phenomena. I will also discuss the impacts of stratospheric ozone depletion and recovery on climate radiative forcing and atmosphere–ocean dynamics. Finally, I will present a storyline approach to future air pollution and how air pollution impacted methane (and thus climate) over the recent past. Collectively, these findings emphasize the critical feedback loops between atmospheric composition and climate dynamics via radiative processes and underscore the need for realistic representation of composition anomalies in weather forecasting systems and climate models.
Short bio:
Prof. Dr Michaela I. Hegglin holds an MSc in Environmental Science (2000) and a PhD in Atmospheric Science (2004) from ETH Zurich in Switzerland. After seven years at the University of Toronto as Postdoc and Research Associate she moved in 2012 to the Meteorology Department at the University of Reading where she progressed through the ranks and was promoted to Full Professor in 2022. Since March 2022 she took on the position as Director of the Institute of Climate and Energy Systems – Stratosphere (ICE-4) at the Research Centre Julich, Germany, and holds a Full Professorship at the University of Wuppertal.
Michaela’s main expertise lies in Earth observations, atmospheric chemistry and transport, upper troposphere and lower stratosphere processes, stratospheric ozone, air pollution, chemistry-climate coupling, and Earth-system model evaluation. She has occupied numerous leadership roles within Future Earth, the World Climate Research Programme, and the World Meteorological Organisation/United Nations Environment Programme (WMO/UNEP) Scientific Assessments of Ozone Depletion, and is currently Principal Investigator of the European Space Agency’s Water Vapour Climate Change Initiative.