It is well established that the ocean is currently losing dissolved oxygen (O2) in response to ocean warming, but the long‐term, equilibrium response of O2 to a warmer climate is neither well quantified nor understood. Here we use idealized multimillennial global warming simulations with a comprehensive Earth systemmodel to show that the equilibrium response in ocean O2 differs fundamentally from the ongoing transient response. After physical equilibration of the model (>4,000 years) under a two times preindustrial CO2 scenario, the deep ocean is better ventilated and oxygenated compared to preindustrial conditions, even though the deep ocean is substantially warmer. The recovery and overshoot of deep convection in the Weddell Sea and especially the Ross Sea after ~720 years causes a strong increase in deep ocean O2 that overcompensates the solubility‐driven decrease in O2. In contrast, O2 in most of the upper tropical ocean is substantially depleted owing to the warming‐induced O2 decrease dominating over changes in ventilation and biology. Our results emphasize the millennial‐scale impact of global warming on marine life, with some impacts emerging many centuries or even millennia after atmospheric CO2 has stabilized.

中文翻译：

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对比上层和深海氧气对持续全球变暖的反应

众所周知，海洋目前正在失去溶解氧 (O2)，以响应海洋变暖，但 O2 对气候变暖的长期平衡响应既没有得到很好的量化，也没有得到很好的理解。在这里，我们使用理想化的千禧年全球变暖模拟和综合地球系统模型来表明海洋 O2 中的平衡响应与持续的瞬态响应有着根本的不同。在两次工业化前 CO2 情景下模型的物理平衡（> 4,000 年）后，与工业化前条件相比，深海的通风和氧化更好，即使深海明显变暖。大约 720 年后威德尔海特别是罗斯海深对流的恢复和超调导致深海 O2 的强烈增加，过度补偿了溶解度驱动的 O2 减少。相比之下，由于变暖引起的 O2 减少主导了通风和生物学的变化，因此大部分上热带海洋中的 O2 大幅枯竭。我们的研究结果强调了全球变暖对海洋生物的千禧年规模影响，一些影响在大气 CO2 稳定后几个世纪甚至数千年后出现。