Scientists warn Atlantic current at risk of shutting down
Scientists warn Atlantic current at risk of shutting down
科学家警告：大西洋洋流面临停滞风险
Ocean currents in the North Atlantic, with warmer colors indicating higher temperatures. NASA As the world careens past our hoped-for target of 1.5 degrees Celsius warming, scientists are growing increasingly alarmed that we may be nearing a dramatic, long-feared “tipping point” — a moment when the main ocean current in the Atlantic Ocean becomes destined to shut down, clamping off the primary source of warmth for northern Europe and playing havoc with the global climate.
北大西洋洋流，暖色调代表更高的温度。（图片来源：NASA）随着全球气温迅速突破我们期望的1.5摄氏度升温目标，科学家们越来越担心我们可能正接近一个长期以来令人恐惧的戏剧性“临界点”——即大西洋主要洋流注定会停滞的时刻。这将切断北欧的主要热量来源，并对全球气候造成严重破坏。
Such a scenario has been a concern for many decades, but the issue is now heating up. “I have personally researched this for 35 years,” says Stefan Rahmstorf, a physical oceanographer at the Potsdam Institute for Climate Impact Research in Germany. “For the first 30 years we considered this a low likelihood event — I would have said a 5 percent chance of occurring. It’s more like 50/50 now. I would even say more likely than not.”
这种情况几十年来一直令人担忧，但现在这一问题正变得愈发紧迫。“我个人研究这个问题已经35年了，”德国波茨坦气候影响研究所的物理海洋学家斯特凡·拉姆斯托夫（Stefan Rahmstorf）说，“在前30年里，我们认为这只是一个低概率事件——我当时会说发生的几率只有5%。但现在看来，几率更像是五五开。我甚至认为发生的可能性比不发生的可能性更大。”
The main ocean current in the Atlantic — the Atlantic Meridional Overturning Circulation — is one of the most powerful drivers of heat around the globe. The AMOC is the reason that northern Europe is so temperate, a couple of degrees warmer than it ought to be given its latitude. In November, Iceland made the unusual move of designating the risk of an AMOC shutdown a national security threat.
大西洋的主要洋流——大西洋经向翻转环流（AMOC）——是全球热量输送的最强大驱动力之一。AMOC是北欧气候如此温和的原因，使其比同纬度地区应有的温度高出几度。去年11月，冰岛采取了不同寻常的举措，将AMOC停滞的风险列为国家安全威胁。
If the AMOC shuts down, its flow slowing to a near halt, the modeled consequences are catastrophic: Europe dries out, affecting agriculture and wildfires; the temperature difference between northern and southern Europe jacks up by a whopping 7 degrees F (4 degrees C), supercharging storms; the vital African and Asian monsoons weaken; and more. An AMOC collapse is also predicted to stir up the Southern Ocean, which could spew out more of its deep carbon into the air, further warming the globe.
如果AMOC停滞，其流速减慢至近乎停止，模型预测的后果将是灾难性的：欧洲将变得干旱，影响农业并加剧野火；南欧和北欧之间的温差将激增高达7华氏度（4摄氏度），从而引发更强烈的风暴；至关重要的非洲和亚洲季风将减弱，等等。此外，AMOC的崩溃预计还会搅动南大洋，可能导致深海中更多的碳被释放到大气中，进一步加剧全球变暖。
Back in 2021, when the Intergovernmental Panel on Climate Change (IPCC) released its most recent assessment of climate science, experts concluded that the AMOC will “very likely” slow down, but that the current’s future wasn’t likely to involve an abrupt collapse before 2100. But more recently several studies have hinted that researchers have been overcautious. “Two or three high-impact papers have come out since then warning that we’re approaching a tipping point and approaching a collapse,” says physical oceanographer Neil Fraser of the Scottish Association for Marine Science in Oban. One of them, published last month, predicts that the AMOC will slow to half of its current flow by the end of the century.
早在2021年，当政府间气候变化专门委员会（IPCC）发布最新的气候科学评估报告时，专家们得出的结论是，AMOC“极有可能”减速，但在2100年之前不太可能发生突然崩溃。但最近的一些研究暗示，研究人员之前的态度过于谨慎了。“自那以后，有两三篇高影响力的论文发表，警告我们正接近一个临界点，并正走向崩溃，”位于奥本的苏格兰海洋科学协会的物理海洋学家尼尔·弗雷泽（Neil Fraser）说。其中一篇上个月发表的论文预测，到本世纪末，AMOC的流速将减慢至目前的一半。
Crew members aboard a scientific expedition in the North Atlantic recover a moored buoy outfitted with sensors that track temperature, salinity, and the speed of flow. Isabela Le Bras / Scripps Institution of Oceanography
北大西洋一次科学考察队的船员们正在回收一个系泊浮标，该浮标配备了追踪温度、盐度和流速的传感器。（图片来源：Isabela Le Bras / 斯克里普斯海洋研究所）
The new worries come from multiple lines of evidence. Researchers have now amassed two decades of solid data on ocean flow, just enough to show a hint of a trend, which suggests the AMOC has begun to slow. To predict the current’s future, researchers turn to models: While there hasn’t been a dramatic improvement in the ability of models to simulate the AMOC, studies focusing on models that best match the real-world data, or that look further into the future, put a pessimistic spin on results.
新的担忧来自多方面的证据。研究人员现在已经积累了二十年关于洋流的可靠数据，足以显示出一种趋势的迹象，表明AMOC已经开始减速。为了预测洋流的未来，研究人员转向模型：虽然模型模拟AMOC的能力并没有显著提高，但那些专注于最符合现实数据或展望更遥远未来的模型研究，得出了悲观的结果。
The science is still far from certain, with a lot hanging on still-limited data and models that disagree with each other wildly. That leaves many scientists unwilling to bet whether we’re close to a tipping point or not. “I absolutely take seriously the existential threat of an AMOC shutdown, and it’s not outside the realm of possibility in the next century,” says Fraser. “I couldn’t pin it down more than that.”
科学结论远未确定，很大程度上取决于仍然有限的数据以及相互之间存在巨大分歧的模型。这使得许多科学家不愿断言我们是否已接近临界点。“我绝对认真对待AMOC停滞带来的生存威胁，这在下个世纪并非完全不可能发生，”弗雷泽说，“我无法给出更确切的定论。”
In October 2024, more than 40 researchers, including Rahmstorf, issued an open letter to the Nordic council of ministers drawing their attention to the “serious risk” of AMOC collapse. Some politicians are sitting up and paying attention. In November 2025, Iceland’s government made the unusual move of designating the risk of an AMOC shutdown a national security threat. “There are some now waking up to the threat,” says Rahmstorf.
2024年10月，包括拉姆斯托夫在内的40多名研究人员向北欧部长理事会发表了一封公开信，提请他们关注AMOC崩溃的“严重风险”。一些政界人士开始重视并关注此事。2025年11月，冰岛政府采取了不同寻常的举措，将AMOC停滞的风险列为国家安全威胁。“现在有些人已经开始意识到这种威胁了，”拉姆斯托夫说。
The two decades of ocean data that researchers have now amassed is just enough to begin to spot possible trends. The AMOC is driven by the formation of deep water near Greenland: Cold, salty water sinks for the simple reason that cold water is more dense than warm water, and salty water is more dense than fresh. This sinking pulls surface waters toward northern Europe from the east coast of the Americas and further south, powering a massive global conveyor belt of water that extends all the way down to the southern tip of Africa.
研究人员目前积累的二十年海洋数据，刚好足以开始发现可能的趋势。AMOC是由格陵兰岛附近的深层水形成所驱动的：寒冷且含盐量高的水会下沉，原因很简单，因为冷水比温水密度大，盐水比淡水密度大。这种下沉作用将美洲东海岸及更南方的表层海水拉向北欧，从而驱动了一个延伸至非洲南端的巨大全球水流传送带。
But as the north warms thanks to climate change, its waters become less dense and therefore less inclined to sink. The current slows. This pulls less salty water up from Africa, making the water in the north even less dense, and even less inclined to sink. The current slows more. Melting ice from Greenland freshens the waters further, exacerbating the problem. Eventually, this feedback loop shuts the current down.
但随着气候变化导致北方变暖，海水密度降低，因此下沉的趋势减弱。洋流随之减慢。这导致从非洲方向输送上来的盐分较少，使得北方的海水密度进一步降低，更难下沉。洋流进一步减慢。格陵兰岛融化的冰川使海水进一步淡化，加剧了这一问题。最终，这种反馈循环会导致洋流彻底停滞。
Something similar has happened before: An AMOC shutdown played havoc with the planet 12,000 years ago, when the end of the last ice age dumped huge amounts of fresh water into the northern ocean. This plunged Europe back into ice-age-like conditions, with Greenland, for example, cooling by a stunning 18 degrees F (10 degrees C). “The effects are amongst the most drastic we have seen in the paleorecord,” says Rahmstorf. “We really don’t want this to happen.”
类似的情况以前也发生过：12,000年前，上一个冰河时代结束时，大量淡水涌入北冰洋，导致AMOC停滞，对地球造成了严重破坏。这使欧洲重新陷入了类似冰河时代的状况，例如格陵兰岛的温度骤降了惊人的18华氏度（10摄氏度）。“这些影响是我们从古气候记录中看到的最剧烈的变化之一，”拉姆斯托夫说，“我们真的不希望这种情况再次发生。”
The AMOC carries warm waters north on the surface of the Atlantic, and cool waters south along the depths. While oceans are warming globally, the North Atlantic is cooling, a sign that the AMOC is weakening. Yale Environment 360 / Adapted from Ruijian Gou
AMOC在大西洋表面将温暖的海水输送到北方，并将寒冷的海水沿深海输送到南方。虽然全球海洋正在变暖，但北大西洋却在变冷，这是AMOC正在减弱的迹象。（图片来源：Yale Environment 360 / 改编自 Ruijian Gou）
Add enough fresh water, and at some point, researchers expect the system to pass a “tipping point” after which collapse becomes inevitable, though it might still take decades to a century to play out. Once the AMOC collapses, the current do
如果加入足够的淡水，研究人员预计在某个时刻，系统将越过一个“临界点”，此后崩溃将变得不可避免，尽管这一过程可能仍需要几十年到一个世纪的时间才会完全显现。一旦AMOC崩溃，洋流将……