Short-lived climate forcers (SLCFs) are aerosols and chemically reactive gases. Due to their physical interactions in the atmosphere, SLCFs play a fundamental role in regional and global climate change. In this talk, I will share examples of how we use different methods and exploit different data sources to address the interaction of aerosols and climate. The tool box includes observational data and model simulations for different spatio-temporal scales, e.g., own data collections on board of research vessels and experiments with Earth system models. I will highlight some of our results for three selected topics. The first topic will illustrate effects and uncertainties of aerosols in experiments with CMIP models as used in the assessment report by the Intergovernmental Panel on Climate Change. Secondly, I will discuss challenges in advancing our understanding of desert-dust aerosols. Thirdly, I will touch on the implication of aerosols and circulation patterns in the transition to weather-dependent power systems.

Some of our research links to ideas for the Aerosol Chemistry Model Intercomparison Project phase two (AerChemMIP2), which I currently plan as one of its three co-chairs. AerChemMIP2 will facilitate a better understanding of the relative contributions of individual SLCF emissions to atmospheric composition change, radiative forcing, and the climate response from the pre-industrial to present-day as well as for projected future emission scenarios in CMIP7. Our AerChemMIP2 experimental protocol builds on methodological knowledge, e.g., gained through other Model Inter-comparison Projects (MIPs) endorsed by CMIP6, and closely aligns with the CMIP7 core experimental design and its listed MIPs. New experiments in AerChemMIP2 will address some of the challenges in understanding Earth system changes, e.g., the role of desert dust and biomass burning aerosols for climate change, for which the community can exploit new observational inventories and model capabilities. The role of SLCFs is a persistent uncertainty in our understanding of Earth’s climate response to human interventions. Output from AerChemMIP2 strives to provide a basis for finding answers. 

The demand for adequate forcing data, e.g., for SLCFs is also increasing in communities outside of CMIP7. This has lead to the demand for regularly updated forcing data in other fields, such as for seasonal to decadal climate predictions. As provider of a CMIP7 forcing data set, I recently followed the invitation to join the Lighthouse Activity for Explaining and Predicting Earth System Changes of the World Climate Research Programme. I am excited to contribute to a better understanding of the fundamental physical understanding of climate change, to share the state of our climate change knowledge in my courses, and to create new joint projects at Heidelberg University and beyond.