Core Insights - Chinese scientists have discovered a new "chemical switch" that controls global climate through subtle changes in ocean sulfate concentrations, which can alter the consumption of seabed methane [1][4] - The study highlights the potential reactivation of this switch due to rapid warming and freshening of the Arctic Ocean, necessitating close monitoring [1][4] Group 1: Research Findings - Methane is the second-largest greenhouse gas after carbon dioxide, with significant amounts stored as hydrates ("flammable ice") on the seabed [3] - Recent studies indicate that most seabed-released methane dissolves in seawater and is consumed by microorganisms, rather than directly entering the atmosphere [3][4] - The research team reconstructed historical carbon dioxide levels in the Arctic Ocean, revealing that 56 million years ago, the region's CO2 concentration was higher than the global average, indicating a shift from a carbon sink to a carbon source [4] Group 2: Implications - The study suggests that a lack of sulfate in the past led to inefficient methane utilization, resulting in increased carbon dioxide emissions, akin to a power plant operating under fuel shortages [4] - The findings serve as a warning that changes in the Arctic's chemical environment could lead to a similar scenario as 56 million years ago, where methane transitions from efficient use to rapid combustion, exacerbating climate change [4]

这是 2023 年 7 月 25 日从 " 雪龙 2" 号极地科考破冰船拍摄的北极圈内的浮冰。新华社记者 魏弘毅 摄 中国科学家于北京时间25日在国际学术期刊《自然·地球科学》发表的论文显示，海洋硫酸盐浓度 的微妙变化，能够改变海底甲烷的消耗方式，就像一个控制全球气候的"化学开关"。随着现代北极海洋 快速变暖和淡化，类似的开关可能被再次激活，需要密切关注。 研究团队基于北极海洋浮游植物"分子化石"重建的二氧化碳浓度显示，5600万年前北极海洋的二氧 化碳浓度水平比全球平均值高，这说明北极海洋从原本吸收二氧化碳的"海绵"变成了排放二氧化碳 的"烟囱"。 研究人员表示，该研究提醒，当北极海水变淡、化学环境改变时，可能重演5600万年前的故事，即 甲烷从高效利用转向快速燃烧，并加剧气候变化，需要密切关注。 该研究由中国科学院广州地球化学研究所与国际合作团队完成。研究人员表示，在5600万年前的超 级变暖事件中，地球经历了极端的全球变暖和海洋酸化。由于该事件与当前气候变化存在诸多相似，一 直备受科学界关注。然而，其背后的碳循环机制，特别是北极海洋发挥的作用始终是未解之谜。 据介绍，甲烷是仅次于二氧化碳的第二大温室气体 ...