MODELING LAND USE CHANGE WITH LINKED CELLULAR AUTOMATA AND SOCIO-ECONOMIC MODELS: A Tool for Exploring the Impact of Climate Change on the Island of St. Lucia

Geographical systems are in many respects the most complex phenomena that we confront, because they constitute the nexus of physical, ecological, and human systems. To be usefully understood, they must be treated as an integrated whole—but also in their parts, and in detail, since many of the most important interactions among their components take place locally. The problem of understanding the possible impacts of climate change immediately poses the question of how to deal with this complexity, because impacts are experienced at all scales from global to local, and the causal chains through which they propagate are both multifarious and characterized by numerous feedback loops. In this chapter we describe a modeling approach that is designed to capture the essentials of the problem by integrating, in a fully dynamic way, models of natural and human systems operating at several spatial scales. The model was developed for the United Nations Environment Program Caribbean Regional Cooperating Unit (UNEP CAR/RCU) (Engelen et al., 1998) with the aim of providing a tool which officials in the region can use to explore possible environmental, social, and economic consequences of hypothesized climate changes. The model is thus generic in the sense that it can accommodate a variety of hypotheses regarding climate change, international economic conditions, and demographic trends, and it can be applied to any small or moderately sized region. The island of St. Lucia was chosen by UNEP as the test application.