The RCPs used in CMIP5 allowed a number of policy-relevant assessments to be made in AR5, providing an important link across the three IPCC working groups (climate science, impacts-adaptation and mitigation). However, the RCPs did not refer to a detailed description of the socio-economic pathways by which each RCP might be realized, nor did they span a plausible range of future emissions for aerosols and other short-lived species. Furthermore, some inconsistencies exist in the RCPs between climate, land-use and anthropogenic, as well as natural emissions. A number of these shortcomings are planned to be addressed in a new generation of scenarios (Van Vuuren et al., 2013) targeted for CMIP6 (Meehl et al. 2014). Referred to as ScenarioMIP, this effort brings together scientists from Integrated Assessment Modeling (IAM), Earth System Modeling, climate impacts-adaptation and mitigation research to develop a set of policy-relevant emission scenarios sampling a range of plausible future development pathways. These will form the basis for a new set of ESM projections in CMIP6. CRESCENDO IAM teams will contribute to the development of this new scenario set and ensure the resulting data is suitable for forcing ESMs.
To increase the utility of ESM projections for climate impact assessment, a sufficient number of simulations are required so a degree of statistical significance can be assigned, both to the simulated Earth system changes and to the resulting impacts. To address this CRESCENDO will generate an ensemble of multi-ESM, multi-member, multi-scenario projections using 2 different resolution versions of the project ESMs (with the lower resolution version being computationally faster). CRESCENDO groups will ensure at least 2-resolution versions of their ESMs are available during the project.
- Meehl, G. A., R. Moss, K. E. Taylor, V. Eyring, R. J. Stouffer, S. Bony, and B. Stevens (2014). Climate Model Intercomparison: Preparing for the Next Phase, Eos, Trans. AGU, 95(9), 77.
- Van Vuuren, D.P. et al. (2013). A new scenario framework for Climate Change Research: scenario matrix architecture. Climatic Change, 122(3), 373-386.