Ocean circulation changes rather than global warming drove temperature trends across the Miocene Climatic Optimum

IF 13.9 1区综合性期刊 Q1 MULTIDISCIPLINARY SCIENCES

Science Advances Pub Date : 2026-10-09 DOI:10.1126/sciadv.adz2555

Evi Wubben, Xiaoqing Liu, Tjerk J. T. Veenstra, R. Paul Acosta, Joyce den Hollander, Chris Overduin, Matthew Huber, Francesca Sangiorgi, Francien Peterse, Appy Sluijs

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引用次数: 0

Abstract

Early-to-Middle Miocene [23 to 13.8 million years ago (Ma)] climates were ∼6° to 9°C warmer than today. Around 16.9 Ma, benthic foraminiferal oxygen isotope (δ¹⁸O) records suggest pronounced warming, known as the Miocene Climatic Optimum (MCO) onset. However, explaining this putative global warming with carbon dioxide (CO₂) forcing faces challenges in terms of timing and forcing magnitude. Our new biomarker-based ocean temperature records, combined with published data, reveal no substantial mean global upper ocean warming across the MCO. Instead, temperature changes differ considerably between sites, with some regions showing cooling. Climate model sensitivity tests indicate that these patterns are best explained by ocean circulation changes, likely due to gateway changes and Antarctic ice sheet variations. This suggests that the MCO signature is better attributed to ocean circulation changes rather than a CO₂-driven global warming event. The δ¹⁸O signal therefore represents warmer deepwater sourcing and/or reduced Antarctic glacial volume, resolving the longstanding challenge of explaining MCO warming without a pronounced CO₂ rise.

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海洋环流的变化而不是全球变暖推动了中新世气候最佳期的温度趋势

中新世早期至中期[2300万至1380万年前（Ma）]的气候比今天温暖约6°至9°C。大约16.9 Ma，底栖有孔虫氧同位素（δ 18o）记录表明明显的变暖，被称为中新世气候最佳（MCO）的开始。然而，用二氧化碳强迫来解释这种假定的全球变暖在时间和强迫强度方面面临挑战。我们新的基于生物标志物的海洋温度记录，结合已发表的数据，显示整个MCO没有实质性的全球海洋上层平均变暖。相反，不同地点之间的温度变化差异很大，有些地区出现降温。气候模式敏感性试验表明，这些模式最好由海洋环流的变化来解释，而海洋环流的变化可能是由于门户变化和南极冰盖的变化。这表明MCO特征更可能归因于海洋环流变化，而不是二氧化碳驱动的全球变暖事件。因此，δ 18o信号代表了更温暖的深水源和/或南极冰川体积的减少，解决了在没有明显二氧化碳上升的情况下解释MCO变暖的长期挑战。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Science Advances 综合性期刊-综合性期刊

CiteScore

21.40

自引率

1.50%

发文量

1937

审稿时长

29 weeks

期刊介绍： Science Advances, an open-access journal by AAAS, publishes impactful research in diverse scientific areas. It aims for fair, fast, and expert peer review, providing freely accessible research to readers. Led by distinguished scientists, the journal supports AAAS's mission by extending Science magazine's capacity to identify and promote significant advances. Evolving digital publishing technologies play a crucial role in advancing AAAS's global mission for science communication and benefitting humankind.