Weakened Miocene temperature response to orbital forcing compared to the modern-day

作者：Y L Zhang, Jilin Wei, Zhen Li, Nan Dai, Weipeng Zheng, Qiuzhen Yin, Agatha M. de Boer, Zhengguo Shi, Lixia Zhang · 发表于：Climate of the past · 年份：2026 · DOI：10.5194/cp-22-879-2026 · 被引用次数：1 · 研究领域：Geology and Paleoclimatology Research、Paleontology and Stratigraphy of Fossils、Evolution and Paleontology Studies

Abstract. Although orbital signal is widely identified in Miocene proxy records, the climate mechanisms linking insolation changes to regional temperature within this warm, low-ice period remains not well known. Here we use fully coupled climate model simulations to assess temperature response to maximum and minimum boreal summer insolation under Miocene and pre-industrial (PI) conditions. Under both conditions, temperature exhibits broadly anti-phased responses to increased and decreased insolation, but the Miocene response is overall weaker, with regionally dependent contrasts and reduced symmetry between two orbital cases. Three notable Miocene-PI differences emerge: (1) reduced boreal continental sensitivity in the Miocene due to dampened albedo, water-vapor and cloud feedbacks in a warmer, low-ice climate; (2) stronger Miocene cooling over tropical North Africa under high insolation, driven by intensified hydrological and moisture-feedbacks supported by a wider Tethys Sea; (3) reversed Southern Ocean anomalies under low insolation, where poleward-restricted Miocene sea ice enables winter insolation changes to trigger positive ice-albedo feedbacks. These results demonstrate that background climate state strongly modulates orbital-scale responses and provide important context for interpreting Miocene proxy records and long-term changes in Earth's climate sensitivity through the Neogene.