THE IMPACT OF RISING CO2 CONCENTRATIONS ON THE TERRESTRIAL BIOSPHERE

Large advances have been made in linking terrestrial biospheric and atmospheric processes in real time. Further, it is now possible to model the potential response of the Earth's primary productivity to the changing climate and to changes in atmospheric CO2 concentration. We still have limited information, however, on the total responses of ecosystems to enhanced CO2 because of the complex web of possible interactions. What is needed are experiments on whole ecosystems under enhanced CO2 in which all of the potential interactions and feedbacks can be monitored, including plant-microbe, plant-herbivore, and plant-atmosphere interactions. A global network of experiments in the major biomes of the world is being developed within the International Geosphere-Biosphere Programme (IGBP) to resolve questions related to the implications of a changed pattern of biomass distribution in the biosphere.