encing migration destination choices. Declining environmental quality and decreasing productivity of land may force people to move. Drastic environmental or climate change may also lead to increased mortality. Thus, it is important to conduct empirical research on both the effects of population dynamics on global change and of global change on population dynamics. In addition, it is important to recognize that relationships between population and global change can operate through or be mediated by other driving forces, such as economic or policy changes. For example, the effect of a resettlement program on an area may depend on the policies of the resettlement agency.
The importance of population processes and trends is already well recognized. Population processes are a central interest of researchers on the human dimensions of global change. We place special emphasis on migration research because we see this as the most urgent need, and as readily linked to other global change research efforts. A focused research effort will support the wider needs of the USGCRP in the following ways:
it will allow a clearer link between human migration and climatic changes. It will provide information on the likely human impacts of events predicted by climate models, identify model outputs of particular importance for impact studies, and possibly alter parameters used as inputs to climate models;
it will provide important socioeconomic and population characteristics as inputs into land use models, thus improving the accuracy of forecasts from such models;
it will provide inputs into models of demand for other environmentally relevant resources, including energy, water, agricultural chemicals, and manufactured goods, thus improving forecasts of burdens on the environment mediated by such demand; and
it will assist the wider USGCRP initiative on integrated assessment by providing straightforward links between projected impacts and possible policy responses on one hand, and the size and distribution of affected populations on the other.
Focused research on population and global change is particularly timely for at least the following reasons:
the population research community has made significant advances toward understanding the relationship between population and socioeconomic change. These advances are the result of techniques and theories that integrate