Recent shifts in the hydrological behavior of natural watersheds suggest acute challenges for water planning under climate change. Usually triggered by a multi-year drought, these shifts involve a tendency for less annual streamflow for a given annual precipitation, and this behavior has now been reported on multiple continents. Future drying under climate change may induce similar unexpected hydrological responses, and this commentary discusses the implications for water planning and management. Commonly used hydrological models poorly represent these shifts in behavior and cannot be relied upon to anticipate future changes. Thus, their use may result in underestimation of hydroclimatic risk and exposure to “surprise” reductions in water supply, relative to projections. The onus is now on hydrologists to determine the underlying causes of shifting behavior and incorporate more dynamic realism into operational models.

中文翻译：

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水文变化威胁水资源

最近自然流域水文行为的变化表明，气候变化下的水资源规划面临严峻挑战。通常由多年干旱引发，这些变化涉及给定年降水量的年流量减少趋势，并且这种行为现在已在多个大洲报道。未来气候变化下的干旱可能会引发类似的意外水文响应，本评论讨论了对水资源规划和管理的影响。常用的水文模型不能很好地反映这些行为变化，并且不能用来预测未来的变化。因此，相对于预测，它们的使用可能导致低估水文气候风险和面临供水“意外”减少的风险。