4. Modelling future climate

‘Modelling future climate’ examines the modelling of future global climate. There is a whole hierarchy of climate models, from relatively simple box models to extremely complex three-dimensional general circulation models (GCMs). Each has a role in examining and furthering the understanding of the global climate system. At the heart of the climate models is the carbon cycle, central to estimating what happens to anthropogenic carbon dioxide and methane emissions. The biggest unknown in the models is the estimation of future human global GHG emissions. It is worth noting here the shared socioeconomic pathways (SSPs) and representative concentration pathways (RCPs), a set of narratives and driving forces that model the possible shape of the global economy and global emissions in the future. The latest IPCC projections on future global temperature, precipitation, and sea level based on the different SSPs make for interesting reading.