The primary drivers of future energy demand in MESSAGE are projections of total population and GDP at purchasing power parity exchange rates, denoted as GDP (GDP|PPP). In developing the In addition to total population, the urban/rural split of population is relevant for MESSAGE-Access version of the model which distinguishes rural and urban population with different household income in developing country regions.
Recent examples of demographic and economic projections used in MESSAGE include the scenarios developed in the Global Energy Assessment (GEA database) as well as the scenarios based on the so-called the Shared Socio-economic Pathway Pathways (SSPSSPs) scenarios, which provide population projections and GDP |(PPP) projections provided by the Organisation for Economic Co-operation and Development (OECD) are used. These projections were developed for the SSP project using the OECD Env-Growth model and MESSAGE currently uses version 9 (dated March 25, 2013). Individual projections are provided for each of the five SSP scenariosat the country level (SSP database).