Global change and food and forest production: future scientific challenges

Production of food and forest products will need to increase to meet the world's projected demand. This challenge can be met by either extensification or intensification but, with little new land available for agriculture in many regions of rapid population growth, intensification will be pre-eminent. Global, average cereal yields will need to rise from the current 2.9 to 4.2 Mg ha(-1) by 2025. The task of increasing production will be made more complex by the additional and interactive effects of changes in climate, atmospheric composition, land use and other global change drivers. However, increasing production with existing technologies will, itself, enhance these major drivers of global change and have other substantial impacts. The global change agenda relating to food and forest products considers research into impacts, adaptation and mitigation. Adaptation and mitigation need to be considered together to harness new technologies (including the use of biotechnology and computer-assisted management schemes) and integrate them with existing technologies in production systems. Better economic, finance and trade policies will also be necessary to allow mon open trade of food and forest products. These factors, together with the positive effects that increased atmospheric CO:! concentration will have on yield will reduce the degree of intensification required to meet demand, thereby mitigating some of the unfavourable environmental consequences. However, there are several social and biophysical management issues associated with intensification that have proven intractable to past research approaches that urgently require resolution. Further research on improving nutrient use efficiency and other aspects of agronomic practice is clearly needed both to increase production and reduce harmful effects on other ecosystems. The effects of fluctuations of weather in the short term on agricultural production systems also warrant further study so that the longer term effects of climate variability and change can be better managed. Multidisciplinary research and interdisciplinary approaches to modelling will be required to apply knowledge both from individual crops to agricultural systems and from plot-scale research to regional food supply issues. (C) 2000 Elsevier Science B.V. All rights reserved.