It is important to note that our experimental design amounts to
investigation of the impact of future irrigation shortfalls on the
pattern of economic activity in the current economy. In this way,
we isolate the effect of irrigation shortage from the effects of other
factors which will inevitably alter the shape of the global economy
in 2030. According to our experience, such projections introduce a
great deal of uncertainty into the experimental design, with
relatively little payoff in terms of additional insights. Therefore, we
run a comparative static simulation in which only basin water
supply is shocked to reflect water available for irrigation in 2030.
This approach is analogous to Hertel et al. (2010) when assessing
the poverty impacts of climate change