ABSTRACT
This chapter addresses scientific scope of global change, the characteristics of the three major components of the global system, the status of the scientific understanding of global change, and what appear to be the most fruitful interactions between science and economics. A variety of forcing agents activate numerous physical processes that move the global system to a new physical state. The aim of global-change scientific research is to understand the role of humans in the forcing agents and to build a predictive understanding of how the planet will respond to these forcings. The trace-gas emissions associated with human activities have perturbed the natural greenhouse balance of the planet, leading to the possibility of global warming. A human perturbation can often cause more than one type of environmental issue. Examples are the chlorofluorocarbons, which contribute to stratospheric ozone depletion and greenhouse warming, and nitrogen oxides and volatile organic compounds, which cause acid rain, smog, and global warming.
