Uncertainty in the predictions of science when applied to the environment is an issue of great current relevance in relation to the impacts of climate change, protecting against natural and man-made disasters, pollutant transport and sustainable resource management. However, it is often ignored both by scientists and decision makers, or interpreted as a conflict or disagreement between scientists. This is not necessarily the case, the scientists might well agree, but their predictions would still be uncertain and knowledge of that uncertainty might be important in decision making."Environmental Modelling: an Uncertain Future?" introduces students, scientists and decision makers to the different concepts and techniques of uncertainty estimation in environmental prediction; the philosophical background to different concepts of uncertainty; the constraint of uncertainties by the collection of observations and data assimilation in real-time forecasting; and techniques for decision making under uncertainty. This book will be relevant to environmental modellers, practitioners and decision makers in hydrology, hydraulics, ecology, meteorology and oceanography, geomorphology, geochemistry, soil science, pollutant transport and climate change.