Climate change is essentially a water problem. Whether it is drought, flood, changing hydrology or rising sea levels, the impacts of climate change all involve water to some extent. Even those who deny that human activities cause climate change must acknowledge that long-term drought cycles in the past (as evidenced by tree rings and other environmental indicators) and wide variations in hydrology can be expected to recur and may be recurring now. Based on the best evidence currently available, precipitation patterns in the near future are likely to be substantially different than in the recent past.

Because of these ongoing changes, the importance of adapting existing legal regimes to changing hydrology cannot be overstated. The competition for water resources is keener now than it has ever been and will only get worse. The list of civilizations that have fallen due to drought is a long one, and with more people, essentially no additional water supplies and different precipitation patterns from what occurred when most water laws were created, water users face significant challenges. This article discusses why conflict over water resources is inevitable; the significance of water as a different type of property and common resource; adapting existing laws and institutions to the changing environment; and the role of reasonableness and physical solution.

Originally published in Water Law & Policy Monitor, 2014 WLPM 9, 02/26/2014.