A Long-term Perspective on Drought in the Great Plains and West

Management of water resources requires an understanding of the full range of natural variability and its consequences. The weather record, which spans the last 100 years or so, provides a snapshot of the contemporary history of drought and its impacts, but this record is relatively short and is inadequate for understanding long-term trends or for evaluating the magnitude of human impacts. A variety of so-called paleoclimatic records - such as tree rings, lake sediments, and sand dunes - record the history of the environment and can be used to extend the record of climatic variation to older intervals of time. These historical archives can provide a perspective on whether or not the patterns of the 20th century are representative of long-term conditions and can be used to enhance management decisions that require long-range estimates of water availabilit