GCMs, emission scenarios, and raster grids used in the Commons

List of General Circulation Models (GCMs) used here

Model Description
(Historic Data) Historic climate data (not a model)
CGCM3 Canadian Centre for Climate Modelling and Analysis CGCM3.1 model
Generalized dissimilarity model Generalized dissimilarity modelling (GDM) is a statistical technique for analysing and predicting spatial patterns of turnover in community composition (beta diversity) across large regions.
GFDL GFDL versions CM 2.0 or CM 2.1
HadCM3 Hadley Centre Coupled Model, version 3
Marsh98 A series of predictions for San Francisco Bay marshplain accretion in response to ranges of initial bed elevation, suspended sediment concentration, organic sediment, and rate of sea level rise.
NCAR CCSM NCAR CCSM, National Center for Atmospheric Research Community Climate System Model
PCM NCAR Parellel Climate Model

List of Emissions Scenarios used in the Commons

Scenario Description

A convergent world with the same global population as in the A1 storyline but with rapid changes in economic structures toward a service and information economy, with reductions in materials intensity, and the introduction of clean and resource-efficient technologies. The emphasis is on global solutions to economic, social, and environmental sustainability, including improved equity, but without additional climate initiatives.


A very heterogeneous world with continuously increasing global population and regionally oriented economic growth that is more fragmented and slower than in other storylines. Fertility patterns across regions converge very slowly, which results in high population growth. Economic development is primarily regionally oriented and per capita economic growth and technological change are more fragmented and slower than in other storylines.


A future world of very rapid economic growth, global population that peaks in mid-century and declines thereafter, and rapid introduction of new and more efficient technologies, with the development balanced across energy sources. Major underlying themes are convergence among regions, capacity building, and increased cultural and social interactions, with a substantial reduction in regional differences in per capita income. The A1B subset to the A1 family of scenarios has a balanced emphasis on all energy sources.