How useful are General Circulation Models (GCMs) for policy makers? Of course, they are considered to be the most powerful models that are presently available for predicting future climates and for carrying out research. Their disadvantage is that they are very time-consuming and very expensive to run for any greenhouse gas emission or concentration scenario. For that reason, GCMs have been run only for a small number of scenarios. However, policy makers are interested in being able to analyze a large number of scenarios. The Integrated Model to Assess the Greenhouse Effect (IMAGE) developed by the National Institute for Public Health and Environmental Protection (RIVM) in the Netherlands is a scientifically based, policy oriented model that can calculate the effect of different greenhouse gas emissions on global surface air temperature and sea level rise. The major advantage of IMAGE is its quick turnaround time. Its disadvantage is that it gives only global values of surface temperature and sea level rise, which have insufficient spatial resolution to estimate ecological impacts on a regional basis. We propose a methodology for combining the fast turnaround time and time-dependent surface temperature results of IMAGE with the spatial resolution of GCMs to provide a linkage between IMAGE and models of ecological change that could provide policy-makers with valuable information about the consequences of different levels of reduction of greenhouse gas emissions
