Clouds and Climate Transitioning to Post-Fossil Aerosol Regime (CleanClouod)

The CleanCloud project investigates how interactions between aerosols and clouds (aerosol–cloud interactions, ACI) will change in the course of the global transition towards a post-fossil society. As anthropogenic aerosol emissions decline, natural aerosol sources are expected to gain increasing importance. In this context, ACI processes in the post-fossil era are likely to differ substantially from pre-industrial conditions, as both the climate and the properties of source regions have changed.

CleanCloud is a Horizon Europe Cluster 5 project involving 20 European research institutions with expertise in remote sensing, laboratory and in situ measurements, aerosol and cloud chamber experiments, and high-resolution modeling of aerosol, cloud, and climate processes. The aim of the project is to better quantify and understand the regional and temporal effects of ACI processes and to assess their evolution during the transition to the post-fossil era.

The main objectives of CleanCloud are to:

• expand process understanding of aerosol and cloud processes and of the relevant aerosol types under future climate regimes,
• reduce uncertainties in climate models through improved representations of ACI, thereby enabling more accurate short- and long-term climate predictions,
• further develop the modeling of ACI through the use of machine learning and the integration of observational data and models,
• deepen the understanding of convective cloud systems, their life cycles, and the role of aerosols in their development and in extreme events,
• support the calibration and validation of satellite-based aerosol and cloud observations and promote their integration into climate models,
• strengthen the exchange between science, policy, and society in order to effectively transfer the latest findings from atmospheric and climate research into policy decision-making processes, and
• provide new scientific foundations for the IPCC and other international climate assessments and increase public awareness of climate issues.