Methane hydrates are widely distributed along continental margins, representing a potential source of methane to the ocean and atmosphere, possibly influencing Earth’s climate. Yet, little is known about the response of methane hydrates to global climate change, especially at the timescale of glacial-interglacial cycles. Here we present a chronology of methane seepage from seep carbonates derived from a series of tens to hundreds of meters long hydrate-bearing sediment records from the South China Sea, drilled at water depths of 664–871 m. We find that six out of seven episodes of intense methane seepage during the last 440,000 years were related to hydrate dissociation, all coinciding with major interglacials, the so-called Marine Isotope Stages 1, 5e, 7c, 9c, and 11c. Using numerical modeling, we show that these events of methane hydrate instability were possibly triggered by the rapid warming of intermediate waters by ~2.5–3.5 °C in the South China Sea. This finding provides direct evidence for the sensitivity of the deep marine methane hydrate reservoir to glacial-interglacial climatic and oceanographic cyclicity.

中文翻译：

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中层水温变暖导致过去间冰期南海甲烷水合物不稳定

甲烷水合物广泛分布于大陆边缘，是海洋和大气中甲烷的潜在来源，可能影响地球气候。然而，人们对甲烷水合物对全球气候变化的反应知之甚少，特别是在冰期-间冰期循环的时间尺度上。在这里，我们提出了渗漏碳酸盐甲烷渗漏的年代学，这些渗漏碳酸盐的甲烷渗漏源自南海一系列数十至数百米长的含水合物沉积物记录，这些记录在水深 664-871 m 处钻探。我们发现，在过去 44 万年中，七次强烈甲烷渗漏中有六次与水合物解离有关，所有这些都与主要间冰期（即所谓的海洋同位素阶段 1、5e、7c、9c 和 11c）同时发生。通过数值模型，我们表明这些甲烷水合物不稳定事件可能是由南海中间水域迅速升温约 2.5-3.5 °C 引发的。这一发现为深层海洋甲烷水合物储层对冰期-间冰期气候和海洋循环的敏感性提供了直接证据。