Chapter Seventeen Challenges in Earth System Modelling: Approaches and Applications

Earth system modelling has taken on increasing importance over the past several years. These models are being used to address an increasing number of environmental and global change problems of societal concern. Perhaps most commonly known is the application to possible greenhouse-gas induced warming. Other compelling problems include the climatic effects of land use changes, aerosols (including sulphate emissions, and smoke from biomass burning), changing trace gas fluxes, interactions and feedbacks with the global carbon cycle and the impacts of changing nutrient fluxes to Earth's ecosystems. While these models have produced many important and exciting results, they are far from perfect, both in terms of the physical processes they attempt to represent and the computational resources required to run them. This chapter focuses on the key challenges that currently confront Earth system modellers in terms of both model development, and how these models can be applied to key outstanding scientific questions of global change.