Simulating the Impact of Global Warming on Regional Pasture Production Environment

Global warming scenarios predict increases in temperatures, evaporation and summer rainfall in the northern two-thirds of Australia. Pasture production models can be combined with spatial climate data in a geographic information system to predict net primary production from pastures. We used a pasture-sheep production model for a phalaris-white clover pasture together with interpolated climatic data to predict the outcome of increases in temperature, evaporation and summer rainfall for net primary production (NPP) from pastures in northern NSW. NPP was predicted to rise in winter due to elevated temperatures, to decline slightly In spring due to increased evaporation, and to change little in summer where increased rainfall and evaporation tended to cancel each other. In autumi1, increased NPP was also predicted. Use of average climatic data smoothed variation. In future, we plan to take account of soil water-holding capacity, elevation, slope, aspect, different plant species, competition and temporal botanical change within the pasture as well as doing sensitivity analyses with a range of climate change scenarios.