Modelling Migration in the Sahel: An Alternative to Cost-Benefit Analysis

Abstract

Environmental issues pose enormous risks for all populations, but especially for the vulnerable. There have been many attempts to measure the risks and the costs of environmental episodes. Such measurement is seen in many quarters as a matter of increasing urgency as a result of the prospect of climate change. The economic approach to vulnerability measurement is based on cost-benefit analysis (CBA). CBA itself is predicated on the proposition that all relevant impacts of climate change can be given a numerical value. A clear argument for this approach was offered by the late David Pearce [13]. The value to be chosen is what the "market" value of the marginal costs and benefits. Where there is no relevant market, individuals must be able to state what they would pay to be able to stay where they are or the money they would accept as an inducement to move from where they are. In many, perhaps most, cases valuation is by no means so simple since actions are taken in response to environmental and political events. In this paper, we investigate one such case concerning the Sahel region at the edge of the Sahara. In the Sahel 1 , typically individuals migrate but who migrates and whither they migrate is a household decision. It would be remarkable if such decisions taken by one household were not influenced by the behaviour of other households. Consequently, any attempt to value migration will depend not only on environmental and political events of the moment but also on the social norms that emerge as household decisions are reached and as those decisions are discussed among members (or heads) of households in the same communities. This sort of social decision making does not fit easily with the sort of economic theory with its monetization arguments on which CBA is based.[8] Due to the way a standard economical approach measures and evaluates cost and benefit, lots of social context in the examined domain gets lost. This social context, in its turn, might have a significant influence on the outcomes of the CBA results and thus be never evaluated. The core question addressed in this paper is whether and how agent-based social simulation can provide a superior alternative to conventional economic analysis. In particular, do models constrained by evidence rather than simplistic theory provide a better guide to policy? The model reported here demonstrates that the answer to this question is in the affirmative. 2 The evidence 2 The Sahel is subject to the greatest climatic variation of any region in the world 3. One feature of this variability is the unpredictable occurrence and duration of droughts. Several studies [1, 14] have assessed the impact of intermittent droughts and their resulting catastrophic effects. These circumstances of the case offer a good testbed for validating the theories postulated by this paper about agent-based modelling being a better alternative to CBA than a conventional economic approach. CBA will be 1 The sourthern edge of the Sahara desert covering parts of Mali, Nigeria, Senegal, Chad, et...

Cost-benefit analysis of migration in the context of environmental change in Ben Tre Province of Viet Nam

“…It should be recognized, however, that very few migration decisions are made based on an analysis of all the above-mentioned cost and benefit factors. Besides, the cost-benefit model mainly collects data related to economic indicators which are quantifiable, while indicators related to social aspects are difficult to collect by this model [19]. In addition, often the poorest people make migration decisions based solely on short-term economic benefits and costs.…”