Stríkis Nicolas Misailidis, Buarque Plácido Fabrício Silva Melo, Cruz Francisco William, Bernal Juan Pablo, Vuille Mathias, Tejedor Ernesto, Santos Matheus Simões, Shimizu Marília Harumi, Ampuero Angela, Du Wenjing, Sampaio Gilvan, Sales Hamilton Dos Reis, Campos José Leandro, Kayano Mary Toshie, Apaèstegui James, Fu Roger R, Cheng Hai, Edwards R Lawrence, Mayta Victor Chavez, Francischini Danielle da Silva, Arruda Marco Aurélio Zezzi, Novello Valdir Felipe
Instituto de Geociências, Universidade de São Paulo (USP), São Paulo, São Paulo-SP, Brazil.
Departamento de Geoquímica, Universidade Federal Fluminense (UFF), Niterói, Rio de Janeiro-RJ, Brazil.
Nat Commun. 2024 Feb 26;15(1):1728. doi: 10.1038/s41467-024-45469-8.
A better understanding of the relative roles of internal climate variability and external contributions, from both natural (solar, volcanic) and anthropogenic greenhouse gas forcing, is important to better project future hydrologic changes. Changes in the evaporative demand play a central role in this context, particularly in tropical areas characterized by high precipitation seasonality, such as the tropical savannah and semi-desertic biomes. Here we present a set of geochemical proxies in speleothems from a well-ventilated cave located in central-eastern Brazil which shows that the evaporative demand is no longer being met by precipitation, leading to a hydrological deficit. A marked change in the hydrologic balance in central-eastern Brazil, caused by a severe warming trend, can be identified, starting in the 1970s. Our findings show that the current aridity has no analog over the last 720 years. A detection and attribution study indicates that this trend is mostly driven by anthropogenic forcing and cannot be explained by natural factors alone. These results reinforce the premise of a severe long-term drought in the subtropics of eastern South America that will likely be further exacerbated in the future given its apparent connection to increased greenhouse gas emissions.
更好地理解内部气候变率以及来自自然（太阳、火山）和人为温室气体强迫的外部因素的相对作用，对于更准确地预测未来水文变化至关重要。在这种情况下，蒸发需求的变化起着核心作用，特别是在降水季节性强的热带地区，如热带稀树草原和半沙漠生物群落。在此，我们展示了巴西中东部一个通风良好的洞穴中石笋的一组地球化学指标，这些指标表明降水已无法满足蒸发需求，导致了水文亏缺。从20世纪70年代开始，可以确定巴西中东部由于严重变暖趋势导致水文平衡发生了显著变化。我们的研究结果表明，当前的干旱在过去720年中没有类似情况。一项检测与归因研究表明，这一趋势主要是由人为强迫驱动的，不能仅由自然因素来解释。这些结果强化了南美洲东部亚热带地区长期严重干旱的前提，鉴于其与温室气体排放增加的明显关联，未来这种干旱可能会进一步加剧。
