Much of the 3C approach employs our derived 100 Bioclimatic Classes (BCCs), based on correlations between vascular plant species records and distributions of abiotic factors (climatic and substrate including landform) developed using generalised dissimilarity modelling (GDM). The BCCs are used as surrogates for overall biodiversity in the subsequent analysis. For the 1990 baseline classification the topo-climate and substrate predictors used in the continental scale GDM floristic model were used in their purely transformed mode. In order to assess the spatial shift in these classes over a number of climate change scenarios, the topo-climate predictors used in the GDM model were ‘projected’ from the 1990 baseline to each of six scenarios that were considered likely under current mitigation policies and emission levels. Only the topo-climate predictors were projected according to the climate change scenarios and the substrate predictors were held the same as the 1990 baseline model.The difference between the 2050 projected transformed predictor values and the 1990 baseline transformed predictor values were interpolated to 5 year intervals and these values were used as cell values for the nearest neighbour classifications.