Bilogical diversity is a rapidly declining global resource. Exploding human populations degrade the environment, destroy the habitas of other species, decimate their populations, and progressively alter the global climate. Setting aside certain areas and protecting them is necessary. It is a vital emergency measure. Nevertheless, with the prospects of impending ‘greenhouse’ induced climatic changes, this may not be enough. A numerical simulation model of the global terrestrial biosphere and quantitative indices of site biological diversity are used to predict the response of potential vegetation to climatic perturbations and to estimate the changes in global biological diversity which may result. This study suggests that climate change is likely to put global biological diversity, in general, and biodiversity in temperate and boreal biomes, in particular, in peril. Moreover, geographically protected areas, such as World Heritage sites, are threatened as well. If conservation is to meet its mandate, if conservation is to actually preserve the variety of life, it cannot limit itself to protecting continents and water bodies. Conservation should also include less tangible resources such as the atmosphere and the global climate.From the standpoint of global biodiversity preservation, limiting the magnitude and/or the rate of climate change would be most beneficial.