Viability, eciency, resilience and equity: using very diverse indicators to deal with uncertainties of future events

International audienceDynamic models can help adapt to climate change since they inform on the impacts of decisions and future events on sustainability. They make it possible to follow the evolution of variables over time, to model exogenous events and adaptive policies and to compute sustainability indicators. Various model types based on dierent worldviews exist, and they give rise to dierent indicators. Modellers generally choose only one type of model, limiting the variety of indicators. However, decision-makers, who have to be creative to face global change, need a wider diversity of indicators. The objective of this paper is to show the diversity of insights one can get by using alternative system indicators and their decision implications. We test our very diverse indicators approach and illustrate its results for a population at risk of ooding and a water-basin manager who can help the population implement protection measures. We test many variations, including e.g. viability theory and agent-based modelling, and dierent indicators of viability, resilience, eciency and equity, based on comparable data sets. We show possible synergies of the obtained diversity of insights: for example, one indicator says that it is urgent to act and another which is the best policy to use. We discuss the diculties of implementation and the benets of our approach for the decision-maker