The SSPs provide narratives describing alternative socio-economic developments. These storylines are a qualitative description of logic relating elements of the narratives to each other.[1] In terms of quantitative elements, they provide data accompanying the scenarios on national population, urbanization and GDP (per capita).[4] The SSPs can be combined with various Integrated Assessment Models (IAMs), to explore possible future pathways both with regards to socioeconomic and climate pathways.[4]