THE PRESENT IS THE KEY TO THE PAST IS THE KEY TO THE FUTURE

Much of our knowledge of geologic materials, features, and past events is based on observation of currently active processes. The concept, “the present is the key to the past” (summarized by Charles Lyell), was developed during the Scottish Enlightenment. During the same period it was recognized that observation of current geologic processes can be used to predict future geologic events. David Hume wrote in 1777: “…all inferences from experience suppose… that the future will resemble the past…” James Hutton wrote in 1788: “… from what has actually been, we have data for concluding with regard to that which is to happen thereafter.” Examples abound of the continuum of geologic processes that have affected and will affect the built environment. Some of these examples come from National Parks. This should be no surprise; many of our National Parks were established expressly to protect and showcase spectacular landscapes created only recently in the geologic past, by processes still active today. But these processes can pose constraints to use of the land in such parks. Few people live in National Parks, of course, but many of us are exposed to the effects of geologic processes in less spectacular young landscapes. A blend of expertise in Quaternary geology, geomorphology, and engineering geology gives many geologists uncommon insight into future events. Such insight is usually underappreciated by public policy makers and taken for granted by the geologist blessed with it. The future effects of geologic processes are so obvious to the geologist that he or she can be frustrated by the lay public’s shortsightedness and ignorance. The resulting misunderstanding can impede communication between the geologist and the very public policy makers who need the geologist’s expertise to minimize the impacts of geologic processes. To communicate better, the geologist can use well-chosen photographs to vividly illustrate geomorphic features and recent evidence of the processes that created them. Such images offer the public a clear demonstration of the continuum of geologic processes that affect the built environment. Understanding these processes enables policymakers to use geologic expertise to minimize impacts on public health, safety, and welfare.