Résumé
With climate change, a number of regions in the world are forecast to face increasingly frequent and more severe droughts. Water users and policy-makers therefore need to define rules and mechanisms to share scarce water in dry periods, when existing water entitlements cannot be fulfilled by available volumes. This paper examines the scarcity-sharing rules embodied in various water right systems for the agricultural sector and their impact on the adoption of drought- mitigation strategies by farmers. It indicates a methodology to measure the value of early warning systems. It also describes flexibility systems to reduce the total cost of drought: markets to reallocate restrictions between farmers; water banks to reallocate allocations across periods; option contracts and insurance systems to reallocate risks.