The Impact of Water Supply Variability on Treaty Cooperation between International Bilateral River Basin Riparian States

This paper assesses the impact of water
supply variability on treaty cooperation between
international bilateral river basin riparian states. Climate
change is anticipated to change the variability of water
supply, as well as its expected magnitude. Previous studies
have focused mainly on water scarcity, measured in terms of
mean precipitation or per capita water availability in the
country, as a trigger for conflict or cooperation. The water
variability measure used here captures both annual runoff
variability and precipitation variability over periods of 30
and 100 years. The analysis used economic and international
relations data to identify incentives for international
cooperation in addressing water supply variability. The
authors find that small-to-moderate increases in variability
create an impetus for cooperation, although large increases
in variability would reduce incentives for treaty
cooperation. Stronger diplomatic and trade relations support
cooperation, while uneven economic power inhibits
cooperation. Various measures of democracy/governance
suggest different impacts on cooperation across the basin
riparians. The findings have policy implications in the
context of preparedness for impacts of climate change on the
water sector.