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A new analysis of streams in the western United States has found that despite a general increase in air temperatures over the past several decades, western streams are not necessarily warming at the same rate. Several factors may influence the discrepancy, including snowmelt, interaction with groundwater, water flow and discharge rates, solar radiation, wind, and humidity. But even after factoring out those elements, the scientists detected cooler-than-expected maximum, mean, and minimum stream temperatures. Looking at streams individually, they found that some seemed to be getting warmer, some cooler, and others showed little change at all.
Results of the research, which was supported by the U.S. Geological Survey, the U.S. Forest Service, and Oregon State University, are published in Geophysical Research Letters, a journal of the American Geophysical Union.