An alternative 'Drivers and Indicators' method is therefore being used within the Environmental Stresses Project at the Hadley Centre for Climate Prediction and Research. This approach simplifies the problem by assuming a range of indicators can be used to determine the level of socio-political stress. 'Driver' variables have been determined which, when undergoing change, drive the 'indicator' variables either away or towards stress. This method has the advantage of being generic and unconstrained by the need to be strictly quantitative. However, its success is dependent upon the judicious choice of both drivers and indicators, and a good understanding not only of the linkages between them, but also linkages between the different driver variables as well as the feedbacks from the indicators to the drivers.
A pilot project is presented in which a GIS system is used to assess the validity of this approach. The work follows up previous studies undertaken in Brazil and China, in which assessments where made of vulnerabilities to environmental stresses. The focus of the work has so far been upon the hydrological system, with its obvious link to water, food and resource scarcity, and the impact changes in components of the hydrological system have upon the indicator variables and hence societal stress.