22 - Predicting the Future Productivity and Distribution of Global Terrestrial Vegetation

Abstract

The climatological community of scientists has provided predictions of how the global climate will change in a future of increasing atmospheric concentrations of greenhouse gases. These predictions emerge from general circulation models (GCMs) that are now capable of providing predictions of the more realistic transient changes in climate that are expected as the concentrations of greenhouse gases steadily increase in the atmosphere. The ecological models that are necessary to interact with these transient climatic changes are those that can predict natural or dynamic changes in the distribution of vegetation. These dynamic global-vegetation models (DGVMs) must therefore be able to predict processes, such as vegetation disturbance and succession, in addition to processes that are now generally included in ecosystem models, such as biogeochemical cycling and carbon dioxide, and water fluxes. This chapter provides general detail and predictions from a DGVM, explains the Sheffield dynamic global-vegetation model (SDGVM) of terrestrial vegetation, and the responses to transient changes in climate over the next 100 years. Overall, net primary productivity (NPP) and net ecosystem productivity (NEP) are predicted to increase, with the most marked increases in NEP (increasing sink capacity) seen at high latitudes in the northern hemisphere.