Information related to the General Circulation Model CGCM3. Andalusia’s Local Climate Change Scenario updated to IPCC’s 5th Report

The General Circulation Model to which this information refers and to which the method of statistical Downscaling of Analogues applies is the CGCM3. The MCG MRI-CGCM3 (Yukimoto et al. (2012)), for its acronym in Meteorological Research Institute (MRI) — Coupled General Circulation Model, version 3, is an atmosphere-ocean coupled model, through the exchange of energy between the two. It has been developed by the Japan Meteorological Research Institute. The AR5 has used a set of four scenarios that do consider climate policies, the so-called Representative Concentration Paths or Representative Concentration Paths (RCPs), see (IPCC, 2013). These CPRs are defined as scenarios covering time series of emissions and concentrations of the full range of chemically active GHGs and aerosols and gases, as well as land use and cover (Moss et al., 2010). The term “representative” means that each concentration trajectory offers one of the many possible scenarios that would lead to the specific characteristics of radiative forcing. The term trajectory emphasises that only long-term concentration levels are of interest, but it also indicates the path followed over time to reach the outcome in question (Moss et al., 2010). Representative concentration trajectories generally refer to the part of the concentration trajectory up to the year 2100, for which integrated assessment models have generated the corresponding emission scenarios. These are identified by the approximate total radiative forcing for the year 2100 compared to 1750, which is considered to be within a range between 2.6 and 8.5 Wm-2. These values should be considered as merely indicative, as the climate forcing resulting from all factors varies from model to model, depending on the characteristics of the model and the treatment of short-lived substances. In the case of RCP6.0 and RCP8.5, the radiative forcing does not reach its maximum until 2100; for CPR2.6, it reaches a maximum and then decreases; and for RCP4.5, it stabilises towards 2100. This new approach leads us to emphasise that, in the functioning of the climate system, the really important thing is not so much the amount of greenhouse gases emitted into the atmosphere, but the way in which these gases modify the energy balance of the planet. Some of the new CPRs allow us to contemplate the effects of policies aimed at limiting climate change in the 21st century. Each CPR is associated with a high-resolution spatial database of emissions of pollutants (sector-classified), GHG emissions and concentrations and land use up to the year 2100, based on a combination of models of varying complexity of atmospheric chemistry and carbon cycle.