Quoted from: Moore, F., Rising, J., Lollo, N. et al. Mimi-PAGE, an open-source implementation of the PAGE09 integrated assessment model. Sci Data 5, 180187 (2018). https://doi.org/10.1038/sdata.2018.187 

PAGE09 model, the latest iteration of the PAGE model, originally developed in 1993 (refs7,11,12). PAGE09 is an eight-region model that takes income, population and emissions policy as inputs, and models the effect of emissions of four different greenhouse gases - carbon dioxide, methane, nitrous oxide, and a collection of other greenhouse gases (termed ‘linear gases’ in PAGE because of the linear relationship between concentration and radiative forcing).

PAGE09 uses a radiative balance climate model to simulate global and regional temperature changes and sea-level rise. Warming and sea-level rise cause damage in 4 different sectors: market sectors (e.g. agriculture, forestry, tourism etc), non-market sectors (e.g. mortality and ecosystem damages), sea-level rise (i.e. coastal flooding) and a stochastic discontinuity (a one-time tipping point resulting in a large loss of GDP). PAGE also models an exogenously-determined adaptation policy that reduces impacts in three of the sectors for a price. Finally, the costs of reducing emissions below their business-as-usual path (called preventative costs in PAGE) are also calculated. PAGE09 simulates outcomes at variable time-steps starting in the default model at 2008 and ending in 2200.

A key feature of PAGE09 is the inclusion of uncertainty distributions (triangular distributions in the default version of the model) for over 100 key scientific and economic parameters. This allows PAGE to be run probabilistically through a Monte Carlo procedure to generate outcome distributions. More details on PAGE09 are given in Hope (2013)7.