Bejarano-Arias Ingrid, Nehme Carole, Breitenbach Sebastian F M, Ionita Monica, Baldini James, Pons-Branchu Edwige, Modestou Sevasti, Umbo Stuart, Mouralis Damase
UMR 6266 IDEES, University of Rouen Normandy/CNRS, Mont St-Aignan, France.
Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, UK.
Sci Rep. 2024 Oct 30;14(1):26049. doi: 10.1038/s41598-024-77674-2.
Drought events are increasingly impacting Europe. The study of past droughts helps disentangle the different factors that trigger hydrological drought, helping to forecast future drought severity. Here we identify the historical drought events of the twentieth and twenty-first centuries in geochemical records of a stalagmite from Caumont cave in Northern France and develop a mechanistic understanding of their root causes. Subannually-resolved stable carbon isotope (δC) and trace element data are directly compared with historical climatic records. δC, Mg, and Sr peaks align well with most of the historical drought events of the twentieth and twenty-first centuries. The comparison reveals a good correspondence between summer effective rainfall and δC, Mg, and Sr concentrations. Further comparison of geochemical records with the precipitation-evapotranspiration index (SPEI) reveals a change in the drought forcings for the past two decades. During most of the twentieth century, droughts appear driven by a pluvial regime, whereas since the late 1990s, drought was driven by higher evapotranspiration due to increased temperature.
干旱事件对欧洲的影响日益加剧。对过去干旱情况的研究有助于厘清引发水文干旱的不同因素，从而有助于预测未来干旱的严重程度。在此，我们通过法国北部卡蒙洞穴石笋的地球化学记录，确定了20世纪和21世纪的历史干旱事件，并对其根源形成了一种机制性的理解。将每年以下分辨率的稳定碳同位素（δC）和微量元素数据直接与历史气候记录进行比较。δC、Mg和Sr峰值与20世纪和21世纪的大多数历史干旱事件高度吻合。比较结果显示，夏季有效降雨量与δC、Mg和Sr浓度之间存在良好的对应关系。将地球化学记录与降水蒸散指数（SPEI）进一步比较后发现，过去二十年干旱的驱动因素发生了变化。在20世纪的大部分时间里，干旱似乎是由多雨模式驱动的，而自20世纪90年代末以来，干旱是由气温升高导致的更高蒸散量驱动的。
