Social and political scientists often predict that future wars will be fought over fresh water instead of oil. The reasons for this are multifold, including: excessive consumption under increasing pressure from rising population; diseases associated with decline in water quality; and geographical... Show moreSocial and political scientists often predict that future wars will be fought over fresh water instead of oil. The reasons for this are multifold, including: excessive consumption under increasing pressure from rising population; diseases associated with decline in water quality; and geographical redistribution of water that could arise from global warming. As geophysical scientists, we tend to see things through a particular lens, attributing first order effects to those governed by the Clausius-Clapeyron equation; most notably, atmospheric water vapor in equilibrium with sea surface temperature. While this first order effect surely is real and consequential, regional outcomes may be neither simple nor easily predictable. I will speak to a few examples that could lead to counter intuitive outcomes. These include: regimes of convective rainfall; effects of anthropogenic aerosol; accumulation of snow in mountainous regions; and factors related to fresh water balance over oceanic regions. Lurking within these topics is the potential for one or more natural disasters, and also potential opportunities for increased productivity. However, since the underlying processes are complex, outcomes are uncertain. These examples may serve to stimulate non-linear thinking, beyond what might prove to be oversimplified expectations, derived from highly parameterized climate system models. Show less
