近日，法国国家科学研究中心Florence Sylvestre团队报道了十年尺度的干旱破坏了撒哈拉沙漠的非洲湿润期。该项研究成果发表在2026年3月25日出版的《自然》杂志上。

在早中全新世期间，撒哈拉与萨赫勒地区经历了湿润期，即所谓的非洲湿润期。该湿润期始于约1.48万年以前，在9,000至6,000年以前达到鼎盛，其间还经历了若干次持续时间较短的干旱事件，但其确切年代与时长尚不明确。

研究组表明，非洲湿润期被两次持续数十年的干旱事件所打断，分别发生在大约9,300年以前和8,200年以前，另有一次约6,300年以前的干旱事件则较难确定。这一发现源于对乍得约阿湖年度纹层状沉积记录的多指标时间序列分析，该记录连续覆盖了过去10,250年。在影响较为显著的8,200年以前的干旱事件中，孢粉、硅藻数据以及叶蜡氢同位素和地球化学物源指示指标均表明，当地降水减少及注入约阿湖的河流水量下降导致了湖泊水位降低，并伴随湖滨芦苇带的扩张。

这些代用指标与该气候模拟结果共同表明，8,200年以前的干旱事件是对大西洋经向翻转环流因北淡水突然注入北大西洋而减弱的直接快速响应。该结果凸显了改进年代际预测能力以更好应对未来此类干旱风险的必要性。

附：英文原文

Title: Decadal-scale droughts disrupted the African Humid Period in the Sahara

Author: Sylvestre, Florence, Melles, Martin, Wennrich, Volker, Dinies, Michle, Chali, Franoise, Swingedouw, Didier, Dallmeyer, Anne, Shi, Xiaoxu, Claussen, Martin, Jaeschke, Andrea, Cocquyt, Christine, Karls, Jens, Kuper, Jan, Mallaye, Baba, Mazur, Jean-Charles, Paills, Christine, Rirongarti, Remadji, Rethemeyer, Janet, Ritter-Prinz, Benedikt, Schefu, Enno, Viehberg, Finn, Wagner, Bernd, Werner, Martin, Yacoub, Abdallah N., Krpelin, Stefan

Issue&Volume: 2026-03-25

Abstract: During the early and mid-Holocene, the Sahara and Sahel experienced a humid phase, the so-called African Humid Period (AHP)1. The AHP started around 14.8thousand years before present (kyrbp), peaked between 9.0 kyrbp and 6.0kyrbp and experienced short-lived droughts of as yet poorly constrained age and duration2,3. Here we show that the AHP was punctuated by two droughts of decadal-scale duration, at about 9.3 kyrbp and 8.2kyrbp, and another more tentatively identified drought at 6.3kyrbp. Our findings arise from a multiproxy time series from the annually layered (varved) sedimentary archive of Lake Yoa in Chad, which covers the past 10.25kyr continuously. During the more prominent drought at 8.2kyrbp, pollen and diatom data, along with leaf-wax isotopes and geochemical source area indicators, imply that a reduction in local precipitation and fluvial supply to Lake Yoa caused a lake-level drop accompanied by an expansion of reed belts along the shore. The proxy data, together with our climate simulations, suggest that the 8.2kyrbp drought event was a direct and rapid response to a potential weakening of the Atlantic Meridional Overturning Circulation (AMOC) owing to sudden freshwater input into the North Atlantic. The results underline the need for improved decadal predictions4 to better anticipate such drought risks in the future.

DOI: 10.1038/s41586-026-10336-7

Source: https://www.nature.com/articles/s41586-026-10336-7