PDF(Pubmed)
Abstract：
Agriculture in the Sahel and much of sub-Saharan Africa remains to a large extent rainfed. At the same time, climate change is already causing less predictable rainfall patterns in the region, even as rising temperatures increase the amount of water needed for agricultural production. We assess to what extent irrigation can strengthen the climate resilience of farming communities. Our study sample consists of nearly 1,000 distinct locations in Mali in which small-scale, river-based irrigation was introduced over the past two decades, as weather conditions worsened and political upheaval erupted. Using the staggered roll-out of the irrigation and repeated observations over 20 years allows us to compare the pre- and postirrigation outcomes of locations while adjusting for confounding factors. We geospatially link data on irrigation interventions with agricultural conditions measured using satellite imagery and surveys, as well as child nutrition and health outcomes and conflict event data. Using a two-way fixed effects model to quasi-experimentally estimate counterfactual outcomes, we find that the introduction of irrigation led to substantial increases in agricultural production on supported fields, with these gains persisting even a decade later. Children in nearby communities are less likely to be stunted or wasted due to the irrigation, and conflict risks decrease in the closest communities. Some of these gains are offset by worsening conditions farther away from the newly installed irrigation. These findings suggest that, even with political conflicts in semi-arid areas already increasing, sustainable irrigation may offer a valuable tool to improve communities\' long-term well-being and social cohesion.
摘要：
萨赫勒地区和撒哈拉以南非洲大部分地区的农业在很大程度上仍在下雨。同时,气候变化已经导致该地区降雨模式难以预测，即使气温上升也会增加农业生产所需的水量。我们评估灌溉在多大程度上可以加强农业社区的气候适应能力。我们的研究样本包括马里近1000个不同的地点，在过去的二十年中引入了基于河流的灌溉，随着天气条件恶化和政治动荡爆发。使用交错展开的灌溉和20年的重复观察，使我们能够比较位置的灌溉前和灌溉后的结果，同时调整混杂因素。我们在地理上将灌溉干预措施的数据与使用卫星图像和调查测量的农业条件联系起来，以及儿童营养和健康结果和冲突事件数据。使用双向固定效应模型准实验估计反事实结果，我们发现，灌溉的引入导致了支持田地上农业产量的大幅增加，这些成就甚至在十年后仍然存在。由于灌溉，附近社区的儿童不太可能发育迟缓或浪费，和冲突风险在最近的社区减少。其中一些收益被远离新安装的灌溉的条件恶化所抵消。这些发现表明,即使半干旱地区的政治冲突已经增加，可持续灌溉可能为改善社区的长期福祉和社会凝聚力提供有价值的工具。
