COMPARISON OF THE EFFECTS OF DIFFERENT CLIMATE CHANGE SCENARIOS ON RANGELAND LIVESTOCK PRODUCTION

The effect of climate change on plant and livestock production in the Great Plains of North America is an important issue. The purpose of this study was to modify an existing rangeland ecosystem model and to simulate a cow/calf production system under different climate scenarios. The project required the capability of simulating rangeland livestock production under different ambient CO2 concentrations, temperatures and precipitation patterns. Climate change scenarios were created from three general circulation models (GCMs): GISS (Goddard Institute for Space Studies model), GFDL (Geophysical Fluid Dynamic Laboratory model), and UKMO (United Kingdom Meteorological Office model). Results from the GCMs were used to modify the climate record for a site in northeastern Colorado. Concomitantly, modifications were made to the SPUR model to help predict the effect of predicted climate change on selected variables of the range/livestock ecosystem. Simulation runs showed that predicted climate change will affect plant and animal production for rangelands. Changes in production were more closely related to changes in temperature and precipitation than to enhanced [CO2] alone. The effect of climate change on livestock production was very complex and results were dependent on the particular GCM scenario being simulated.