Improving Business-as-Usual Scenarios in Land Change Modelling by Extending the Calibration Period and Integrating Demographic Data

Abstract

Land use and land cover change (LUCC) models are increasingly being used to anticipate the future of territories, particularly through the prospective scenario method. In the case of so-called trend or Business-as-Usual (BAU) scenarios, the aim is to observe the current dynamics and to extend them into the future. However, as they are implemented as baseline simulation in most current software packages, BAU scenarios are calibrated from a training period built from only two dates. We argue that this limits the quantitative estimation of future change intensity, and we illustrate it from a simple model of deforestation in Northern Ecuadorian Amazon using the Land Change Modeler (LCM) software package. This paper proposes a contribution to improve BAU scenarios calibration by mainly two enhancements: taking into account a longer calibration period for estimating change quantities and the integration of thematic data in change probabilities matrices. We thus demonstrate the need to exceed the linear construction of BAU scenarios as well as the need to integrate thematic and particularly socio-demographic data into the estimation of future quantities of change. The spatial aspects of our quantitative adjustments are discussed and tend to show that improvements in the quantitative aspects should not be dissociated from an improvement in the spatial allocation of changes, which may lead to a decrease in the predictive accuracy of the simulations.

Evaluating Spatial Scenarios for Sustainable Development in Quito, Ecuador

“…Two scenarios were developed. Scenario 1, the trend or business-as-usual (BAU) [2] scenario, shows the growth trend in the current context until the year 2050, i.e., growth under conditions with little or no regulation. It is based on the premise that changes in land use (influenced by factors or driving forces such as roads, equipment or land market) that have happened in the past will continue.…”

“…Urban sprawl is a phenomenon that is changing landscapes throughout Latin America [1]. The physical expansion of cities occurs at the expense of agricultural, forest or natural areas without taking into account whether these lands were designated for urban land use or not, thereby deteriorating the natural resources that sustain the city [2]. Increasing land consumption and relatively low population density have become features of the peri-urban areas of major cities [3].…”