We target significant scientific gaps identified in the IPCC AR6 (2021) and support our conclusions by undertaking comparisons with CMIP6 ensemble of models to evaluate the results. The overall aim of the project is to improve our knowledge of individual and cumulative contribution of non-CO2 radiative forcers and their precursors. Our integrated observational and modelling analysis is focusing on the radiative forcing properties of PM2.5/PM10 CCN and their components (e.g. POA, SOA, BC/EC, SIA, dust), O3 (and its precursors NOx, VOCs, SO2, CO, CH4, and N2O in the wider context of the warming potential of all key GHGs.
The main objective of WP1 during the first 18 months was to build a detailed and comprehensive observationally-based dataset on anthropogenic non-CO2 species including climate-relevant gases and aerosol properties that will be used to constrain numerical sensitivity simulations. This was delivered in D1.1 in terms of the database GHOST. Similarly, the main objective of WP2 was the same, but for natural aerosols. These data are described in D2.1.
In WP3 and WP4, the efforts were aimed to improve and evaluate state-of-the-art global ESMs (WP3) and regional climate and atmospheric composition models (RCMs) (WP4), targeting specific critical processes with the largest uncertainties for improving future next generation climate projections over the spread of scales, planned in WP6. For that, adequate scenarios and emissions are necessary, which was studied in WP5, where significant inconsistency between what is used in standard scenarios for global ESMs, and what is needed for regional couples of RCMs and CTMs, were found and solved. However, significant differences were found in these “standard” emission inventories as some kind of by-product.
In WP7 effort started on localization and optimization of standard emission scenarios, with potential engagement of stakeholders.