A ‘cold blob’ in the Atlantic could be a sign of AMOC shutdown

大西洋中的“冷斑”可能是大西洋经向翻转环流（AMOC）即将崩溃的信号

A mysterious cold patch in the North Atlantic has puzzled scientists for years. New research links the cooling to a weakening system of Atlantic Ocean currents that researchers warn could reach a tipping point. The shutdown of these currents would bring catastrophic changes to weather and climate across multiple continents. 北大西洋中一块神秘的寒冷区域多年来一直困扰着科学家。最新研究将这种降温现象与大西洋洋流系统的减弱联系起来，研究人员警告称，该系统可能已临近临界点。一旦这些洋流停止运转，将给各大洲的天气和气候带来灾难性的变化。

In the North Atlantic Ocean, south of Greenland and Iceland, a large patch of water is doing something very strange. While the rest of the ocean heats up, it’s been getting colder. A new study says it has the answer to this mystery — and it’s an ominous sign the world is hurtling toward one of the most alarming climate tipping points. 在格陵兰岛和冰岛以南的北大西洋海域，一大片水域正出现异常现象。当海洋的其他部分都在变暖时，这片区域却在持续变冷。一项新研究声称找到了这个谜团的答案——这预示着全球正加速迈向最令人担忧的气候临界点之一。

The swath of ocean — dubbed the “cold blob” or “warming hole” — has cooled by nearly 1 degree Celsius (1.8 Fahrenheit) since 1900. Scientists have long debated whether this anomaly is driven by heat loss from the ocean surface due to changes to winds and clouds, or whether it’s a signal of the weakening of a critical system of ocean currents, which transports heat. The new research concludes it’s the latter, and the finding points to a worrying future. 这片被称为“冷斑”或“变暖空洞”的海域自1900年以来已降温近1摄氏度（1.8华氏度）。长期以来，科学家们一直在争论这种异常现象是由风和云的变化导致的海面热量流失所致，还是由负责输送热量的关键洋流系统减弱所发出的信号。最新研究得出的结论是后者，这一发现预示着令人担忧的未来。

The Atlantic Meridional Overturning Circulation, or AMOC, works like a vast ocean conveyor belt, pulling warm water from the tropics to the Northern Hemisphere, where it cools, sinks and flows back south. A raft of research suggests this system is weakening as human-driven global warming melts ice and causes a surge of freshwater into the ocean, disrupting the AMOC’s delicate balance of heat and salinity. 大西洋经向翻转环流（AMOC）就像一条巨大的海洋传送带，将热带地区的暖水输送到北半球，在那里冷却、下沉并流回南方。大量研究表明，随着人类活动导致的全球变暖使冰川融化，大量淡水涌入海洋，破坏了AMOC热量和盐度的微妙平衡，该系统正在减弱。

Some scientists warn the AMOC is heading toward a tipping point, potentially as early as this century, which would mean a future collapse is locked in. An AMOC shutdown would be a global catastrophe, causing accelerated sea level rise on the US East Coast, plunging Europe into a winter deep freeze and shifting the monsoon in Africa, driving prolonged droughts. 一些科学家警告称，AMOC正走向一个临界点，最早可能在本世纪内发生，这意味着未来的崩溃已不可避免。AMOC的停止将是一场全球性灾难，会导致美国东海岸海平面加速上升，使欧洲陷入严冬，并改变非洲的季风模式，引发长期干旱。

The cold blob has been interpreted by some as a fingerprint of AMOC change, because it’s the region to which the AMOC brings much of its heat. To better unravel what’s happening in this part of the Atlantic, the study scientists combined real-world ocean heat data from instruments and satellites with climate models. They found that cooling in the cold blob was not just happening on the surface but also deep in the ocean, where atmospheric conditions like winds and clouds have a much weaker influence. 一些人将“冷斑”解读为AMOC变化的指纹，因为该区域正是AMOC输送大量热量的目的地。为了更好地揭示大西洋这一区域正在发生的事情，研究人员将来自仪器和卫星的真实海洋热量数据与气候模型相结合。他们发现，“冷斑”的降温不仅发生在海面，也发生在深海，而深海受风和云等大气条件的影响要小得多。

All signs point to the influence of the AMOC, the study found. “It is changing ocean heat transport” which is driving the cooling of the cold blob, said Stefan Rahmstorf, a study author and a physics and oceans professor at Potsdam University, Germany. There is also plenty of other evidence the AMOC is weakening, independent of the cold blob, he added, with some studies suggesting it’s at the weakest it’s been in around 1,000 years. 研究发现，所有迹象都指向了AMOC的影响。该研究作者、德国波茨坦大学物理与海洋学教授斯特凡·拉姆斯托夫（Stefan Rahmstorf）表示：“它正在改变海洋热量输送”，从而驱动了“冷斑”的降温。他补充说，除了“冷斑”之外，还有大量其他证据表明AMOC正在减弱，一些研究甚至指出其强度已降至约1000年来的最低点。

Previous studies have demonstrated it’s possible to generate a cold blob through atmospheric conditions alone, said René van Westen, a marine and atmospheric researcher at Utrecht University, who was not involved in the research. But the fact the new study found consistent results across different datasets “strengthens the robustness of the conclusions,” he said. 未参与此项研究的乌得勒支大学海洋与大气研究员勒内·范·韦斯滕（René van Westen）表示，先前的研究已经证明，仅通过大气条件也有可能产生“冷斑”。但他指出，这项新研究在不同数据集上得出了结论一致的结果，“增强了结论的稳健性”。

David Thornally, a professor of ocean and climate science at University College London, also not involved in the research, said that the study bolsters evidence of a link between the cold blob and a weakening AMOC, but cautioned that the sparseness of real-world data means the available datasets “are best viewed as good approximations rather than perfect representations of reality.” Uncertainties remain, he told CNN, and “I don’t think (this study) will be the final word on the issue.” 同样未参与研究的伦敦大学学院海洋与气候科学教授大卫·索纳利（David Thornally）表示，该研究加强了“冷斑”与AMOC减弱之间存在联系的证据，但他提醒称，由于真实世界数据的稀缺，现有的数据集“最好被视为良好的近似值，而非对现实的完美呈现”。他告诉CNN，不确定性依然存在，“我不认为（这项研究）会是该问题的最终定论。”

Jonathan Baker, a senior climate scientist at the UK Met Office, agreed, telling CNN “I would view this study as adding evidence for an AMOC contribution to the cold blob, rather than definitively settling the question.” 英国气象局高级气候科学家乔纳森·贝克（Jonathan Baker）对此表示赞同，他告诉CNN：“我认为这项研究为AMOC对‘冷斑’的贡献提供了更多证据，而不是最终解决了这个问题。”