Water allocation policies play a key role in determining the impact of drought events on the macroeconomic system. Economic agents may find it difficult to modify their production structure immediately, and will therefore try to maintain current production and commercial patterns. The study takes this behavior into account and combines a Multi-Regional Input-Output model with a Non-Linear Programming optimization model to assess the macroeconomic impacts of localized droughts on a global scale. It analyses their propagation through interconnected supply chains, and it also evaluates the implications of different water allocation policies in terms of GDP impacts, with a large regional and sectoral detail. Our results show that the policy-regime chosen greatly determines the extent of the economic impacts, both in the directly affected region and in third countries. When the drought affects only agriculture, that negative economic impacts can be mitigated by adjusting production and trade. In contrast, when water availability is reduced uniformly across all economic sectors in the drought-stricken region, economic losses spread across the globe.

水资源分配政策在决定干旱事件对宏观经济系统的影响方面起着关键作用。经济主体可能会发现很难立即改变他们的生产结构，因此会努力维持当前的生产和商业模式。该研究将这种行为考虑在内，并将多区域投入产出模型与非线性规划优化模型相结合，以评估全球范围内局部干旱的宏观经济影响。它分析了它们通过相互关联的供应链的传播，还评估了不同水资源分配政策对 GDP 影响的影响，具有大量的区域和部门细节。我们的结果表明，所选择的政策制度在很大程度上决定了经济影响的程度，在直接受影响的地区和第三国。当干旱只影响农业时，可以通过调整生产和贸易来减轻负面经济影响。相比之下，当受干旱影响的地区所有经济部门的可用水量统一减少时，经济损失就会蔓延到全球。