MODELING AND PREDICTING HUMAN IMPACT ON LANDSCAPE

Human impact on landscape is magnified by technology. Through the action of Moore’s law, modern technology, driven by computation, is an exponentiating phenomenon. Technology has led to exponential growth of the earth’s human population and continues to provide tools that can amplify the impact of single human beings. As a consequence, human impact on landscape resources – water, vegetation, soil, minerals, and space – also expands at an exponential rate. Prediction of the nature and implications of landscape change is critical for our well-being and survival. Numerical approaches to prediction of climate change suggest a course of action for modeling landscape change, but climate predictions require assumptions about future human behavior and remain highly uncertain, whatever their mathematical sophistication. Modeling and prediction in hydrology, geomorphology and ecology are even more uncertain than climate modeling, in fact vastly more so, because these systems are such strong functions of their own histories. A key purpose of landscape prediction is to anticipate the trajectory of landscape change as conditioned on actions under our control so that a choice of action can be made that will drive change in a desired direction. A meaningful alternative to models that are intended to make believable long range predictions – an essentially impossible task for any large complex geologic system, be it the atmosphere or Yucca Mountain – is short range prediction combined with corrective action to adjust the trajectory when it does not go in the anticipated direction. This is the default predictive method designed by evolution and used by all higher animals, including man, to survive in a complex world. The particular challenge posed by exponentiating human impact on landscape is that the “headlight distance”, the length of time we can reliably see into the future and thus the time available for modeling, prediction, and considered action, is rapidly shrinking.