Earth system modeling of climate geoengineering proposals suggests that the physical outcomes of such interventions will depend on the particulars of the implementation. Here, we present a first attempt to “geoengineer” a well-known teleconnection between sea surface temperatures (SSTs) and Sahelian precipitation. Using idealized earth system model simulations, we show that selectively cooling the Indian Ocean efficiently increases precipitation in the Sahel region, widening the seasonally migrating rainband over Africa. Applying the SST perturbations derived from the idealized experiments to observationally constrained historical ones, we find that our intervention can reverse conditions as extreme as the mid-20th century Sahelian drought, albeit less efficiently than in the idealized simulations. Side effects include changes in the seasonal distribution of Sahelian precipitation and substantial precipitation reductions in sub-Saharan East Africa. This work represents a proof-of-concept illustration of effects that might be expected with a tailored, regional approach to climate intervention.

中文翻译：

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扭转萨赫勒干旱

气候地球工程提案的地球系统建模表明，此类干预措施的物理结果将取决于实施的具体情况。在这里，我们首次尝试对海面温度 (SST) 和萨赫勒降水之间众所周知的遥相关进行“地球工程”。使用理想化的地球系统模型模拟，我们表明选择性冷却印度洋有效地增加了萨赫勒地区的降水，扩大了非洲的季节性迁移雨带。将源自理想化实验的 SST 扰动应用于观测受限的历史实验，我们发现我们的干预可以逆转 20 世纪中叶萨赫勒干旱等极端条件，尽管效率不如理想化模拟。副作用包括萨赫勒地区降水季节性分布的变化和撒哈拉以南东非地区降水量的大幅减少。这项工作代表了通过量身定制的区域气候干预方法可能产生的影响的概念验证说明。