13万年前南极高速绕极流导致冰盖消融加剧

Core Insights - The research conducted by Hainan University's marine carbon and nitrogen cycle team reveals that during the last interglacial warm period approximately 130,000 years ago, the southern boundary of the Antarctic Circumpolar Current (ACC) flowed at three times the modern speed and shifted southward by over five degrees, leading to increased melting of the Antarctic ice sheet [1][2] Group 1: Research Findings - The Antarctic Circumpolar Current is the largest ocean current on Earth, crucial for global heat transport, carbon cycling, and nutrient exchange between oceans [1] - The research utilized sediment core samples from the Scotia Sea, drilled at depths of 3000-4000 meters, employing a novel method to analyze particle size distribution, which indicated that the flow speed of the ACC during the last interglacial was three times that of today [1] - The study found that the southward shift of the ACC's southern boundary was over 600 kilometers, correlating with peaks in Earth's orbital eccentricity, which intensified the melting of the Antarctic ice sheet, resulting in global sea levels being 6-9 meters higher than present [1] Group 2: Implications for Climate Research - This discovery prompts a reevaluation of the relationship between ancient and modern climate systems, challenging the previous belief that current climate changes mirror those of the last interglacial period [2] - The research indicates that differences between the two periods arise from variations in solar radiation due to changes in Earth's orbital parameters, which significantly affected the strength and distribution of westerly winds driving the ACC [2] - The study suggests that with current and future low values of Earth's orbital eccentricity and precession, the ACC may shift northward, potentially counteracting the southward movement caused by climate warming, providing a critical benchmark for predicting future global climate changes [2]