Dimming the Sun Would Help Lower the Risks of El Niño
Dimming the Sun Would Help Lower the Risks of El Niño
遮蔽阳光有助于降低厄尔尼诺现象带来的风险
This year’s El Niño is shaping up to be among the strongest on record, and it’s set to create chaotic weather around the world. 今年的厄尔尼诺现象正成为有记录以来最强的一次，预计将在全球范围内引发混乱的天气。
A new study suggests that there could be a way to mitigate some of the impacts of future El Niños and global warming: dimming the sun. 一项新的研究表明，或许有一种方法可以减轻未来厄尔尼诺现象和全球变暖带来的部分影响：遮蔽阳光。
El Niño develops naturally in the tropical Pacific every few years, caused by weakened trade winds that push heat from the ocean toward the coast of South America. This tilts the odds toward higher-than-average global temperatures, as well as droughts in some regions, intense rains and floods in others, and more cyclones in the Pacific. Piled on top of warming driven by burning fossil fuels, a strong El Niño can mean hundreds of billions in economic losses. 厄尔尼诺现象每隔几年就会在热带太平洋自然形成，其成因是信风减弱，导致海洋热量向南美洲海岸移动。这会增加全球平均气温升高的可能性，并导致某些地区出现干旱，另一些地区出现强降雨和洪水，以及太平洋地区气旋增多。在化石燃料燃烧导致的全球变暖基础上，强厄尔尼诺现象可能意味着数千亿美元的经济损失。
The new study argues that deflecting solar energy could cool the ocean and help moderate El Niño events before they become too strong, staving off the worst impacts. 这项新研究认为，偏转太阳能可以冷却海洋，并有助于在厄尔尼诺事件变得过于强烈之前对其进行调节，从而避免最严重的后果。
“El Niño is one of these things where something happens in the tropical Pacific, and then it rearranges the way the entire global atmosphere is holding energy that year,” says Katherine Ricke, a coauthor of the study published Wednesday in the journal Science Advances and a climate scientist at UC San Diego and the Scripps Institution of Oceanography. “It’s an ultimate pressure point in the climate system.” “厄尔尼诺现象属于那种在热带太平洋发生后，会重新调整当年全球大气能量分布的事件，”该研究的合著者、加州大学圣地亚哥分校及斯克里普斯海洋研究所的气候科学家凯瑟琳·里克（Katherine Ricke）表示，该研究于周三发表在《科学进展》（Science Advances）杂志上。“它是气候系统中的一个终极压力点。”
Ricke and her coauthors looked at using marine cloud brightening, or MCB, as a way to dim the sun in the Pacific. The technique entails spraying seawater into marine clouds to enhance the clouds’ reflectivity. While some pilot projects and randomized controlled trials have tested the technique’s efficacy, they’ve only been on very small scales. 里克和她的合著者研究了利用海洋云增亮（MCB）作为遮蔽太平洋阳光的一种方法。该技术需要将海水喷洒到海洋云层中，以增强云层的反射率。虽然一些试点项目和随机对照试验已经测试了该技术的有效性，但它们仅处于非常小的规模。
MCB is one of a few different solar geoengineering methods intended to reflect sunlight back into space. Other methods, like using planes to inject aerosols into the stratosphere, can only work globally. But MCB has the potential to be a regional cooling solution. 海洋云增亮是旨在将阳光反射回太空的几种太阳能地球工程方法之一。其他方法，例如使用飞机向平流层注入气溶胶，只能在全球范围内发挥作用。但海洋云增亮有潜力成为一种区域性的降温解决方案。
To get around the lack of MCB experiments, researchers looked at a recent natural phenomenon that mimicked it: the catastrophic 2019-2020 Australian bushfire season. More than 10,000 bushfires raged across the country, producing almost 1 million metric tons of smoke. That represents one of the largest inputs of smoke into the stratosphere that humans have observed with satellite technology. 为了弥补海洋云增亮实验的不足，研究人员观察了近期一个模拟了该现象的自然事件：2019-2020年澳大利亚灾难性的丛林大火。当时全国发生了1万多起丛林大火，产生了近100万公吨的烟雾。这是人类利用卫星技术观测到的向平流层输入烟雾量最大的事件之一。
While the effects of this massive amount of smoke were complex, previous research shows it helped trigger a rare triple-dip La Niña—the opposite phase of El Niño—thanks in part to reflective particles in the smoke. 虽然这些大量烟雾的影响很复杂，但先前的研究表明，部分归功于烟雾中的反射颗粒，它促成了一次罕见的“三重拉尼娜”现象（厄尔尼诺的相反阶段）。
This event, Ricke says, enabled her and her coauthors to finally address a question they’d had for years about whether regional interventions can help relieve the pressure events like El Niño put on the global climate system. The researchers created a model based on the MCB effects of the Australian bushfires, and ran it against two different historic El Niño events to observe its effects. The modeling showed that lowering the amount of sunlight reaching the Pacific’s surface would have significantly reduced the magnitude of those El Niño events and their global impact. 里克表示，这一事件使她和合著者终于能够解决他们多年来的一个疑问：区域性干预措施是否能帮助缓解厄尔尼诺等事件给全球气候系统带来的压力。研究人员基于澳大利亚丛林大火的海洋云增亮效应建立了一个模型，并将其应用于两次不同的历史厄尔尼诺事件中以观察其效果。模型显示，减少到达太平洋表面的阳光量，本可以显著降低这些厄尔尼诺事件的强度及其全球影响。
Geoengineering techniques have traditionally been viewed as a method to cool the entire planet, acting as a counterbalance to humans’ use of fossil fuels—albeit an extremely controversial one. The new study makes the case that some forms of geoengineering would be better used to target regional events, like El Niño. Doing so has the potential to avoid—or at least lower the risk—of the compounding effects of El Niño piled on top of rising temperatures due to human activity. 地球工程技术传统上被视为一种冷却整个地球的方法，用以抵消人类对化石燃料的使用——尽管这极具争议。这项新研究提出，某些形式的地球工程更适合用于针对区域性事件，如厄尔尼诺现象。这样做有可能避免——或至少降低——厄尔尼诺现象与人类活动导致的气温上升叠加所产生的复合效应风险。
“The idea of having to sustain geoengineering indefinitely gives a lot of people pause—we all understand that cooperation at that magnitude would be hugely complicated in the world we live in,” Ricke says. “This is a totally different way to think about geoengineering.” “必须无限期维持地球工程的想法让许多人感到迟疑——我们都明白，在我们生活的这个世界上，如此大规模的合作将极其复杂，”里克说。“这是一种思考地球工程的全新方式。”
Geoengineering techniques like using planes to inject aerosols into the stratosphere—or even more fantastical ideas like space mirrors—have been met with skepticism from scientists, policymakers, and the public. This is mainly due to their unpredictability—altering the weather can come with a lot of unintended consequences—and their potential to create political instability. It’s likely even a regionalized approach like the one proposed in the new study would run into the same issues, but it appears to be scientifically feasible—or at least worth further study. 诸如使用飞机向平流层注入气溶胶之类的地球工程技术，甚至像太空镜这样更具幻想色彩的想法，都遭到了科学家、政策制定者和公众的质疑。这主要是因为它们具有不可预测性——改变天气可能会带来许多意想不到的后果——以及它们可能造成政治不稳定。即使是新研究中提出的这种区域化方法，也很可能会遇到同样的问题，但它在科学上似乎是可行的，或者至少值得进一步研究。
“The thesis seems quite reasonable,” Andrew Dessler, a professor of atmospheric science at Texas A&M University, says of the Scripps study. But Dessler warns that actually executing something like this would be “a political nightmare,” resulting in conflict or war if something goes wrong in what would be a worst-case scenario. “这个论点看起来相当合理，”德克萨斯农工大学大气科学教授安德鲁·德斯勒（Andrew Dessler）在评价斯克里普斯的研究时说。但德斯勒警告称，实际执行这样的计划将是“一场政治噩梦”，如果最坏的情况发生且出现差错，可能会导致冲突或战争。
“These models are imperfect, and there’s the possibility that you’ll create an unpredicted problem that is worse than the problem you’re trying to solve,” Dessler says. “I think this is a really interesting paper, and I learned a few things reading it, but I certainly would not say that this is a great idea and we should implement it.” “这些模型并不完美，而且你可能会制造出一个比你试图解决的问题更糟糕的不可预见的问题，”德斯勒说。“我认为这是一篇非常有趣的论文，我在阅读时学到了一些东西，但我绝不会说这是一个好主意，我们应该去实施它。”
Ricke agrees: “There’s a lot of things we need to figure out from models before trying it in the real world,” she says. Still, she says, this research could prove crucial for the future if humanity fails to address fossil fuel pollution. “The reason people do research on solar geoengineering is because we might end up in a world where we need it.” 里克对此表示赞同：“在现实世界中尝试之前，我们需要从模型中弄清楚很多事情，”她说。不过她也表示，如果人类无法解决化石燃料污染问题，这项研究对未来可能至关重要。“人们研究太阳能地球工程的原因是，我们最终可能生活在一个需要它的世界里。”