There are a number of climate models that forecast changes in ocean parameters over the next century. One class of model used for this purpose is the coupled general circulation model. The Canadian Centre for Climate Modeling and Analysis (CCCma) runs such a model, the Centre’s most recent version is its third generation coupled general circulation model (CGCM3). The Centre runs the model with a series of scenarios or storylines suggesting varying degrees of population and economic growth and conservation (note that these are internationally agreed scenarios used by other modeling centers). The primary anthropogenic drivers of climate change are greenhouse gases such as CO2, thus the different scenarios can be represented by the expected CO2 concentrations in the atmosphere over the next century. The change in CO2 levels can be judged by the benchmark levels associated with those observed during the 20th century. In the committed scenario, CO2 levels are kept at current concentrations, which would require the immediate cessation of fossil fuel use. Scenarios B1, A1B and A2 represent different conservation strategies and socio-economic responses to changes in energy use and delivery. The most pessimistic scenario is A2 which suggests little will be done to stem the deposition of CO2 into the atmosphere.