Volcanoes that made history

改变历史的火山

The first telegram arrived in Singapore on a Monday, sent from the city of Batavia in the Dutch East Indies (now Jakarta, Indonesia). “Terrific detonations from Krakatau (volcanic island),” it reported. Soon afterward: “Stones falling. Village near Anjer washed away.” The wires continued clattering out news of bridges destroyed, boats smashed, lighthouses “disappeared.” By noon on Tuesday, the scope of the natural disaster was clear: “Where once Mount Krakatau stood the sea now plays.” 第一封电报于周一抵达新加坡，是从荷属东印度群岛的巴达维亚（现印度尼西亚雅加达）发出的。电报称：“喀拉喀托（火山岛）发生剧烈爆炸。”不久后又报道：“落石不断。安耶尔附近的村庄被冲毁。”电报线持续传出桥梁被毁、船只破碎、灯塔“消失”的消息。到周二中午，这场自然灾害的规模已显而易见：“曾经矗立着喀拉喀托火山的地方，如今已是汪洋一片。”

Within days, the source of the destruction was known worldwide. On the morning of August 27, 1883, a volcanic eruption had obliterated two islands in the strait between Java and Sumatra, and most of a third. More than 36,000 people perished, the majority in devastating tsunamis that raced outward from the colossal explosion. Thanks to Victorian-era telecommunications, it was the first time in history that people around the globe could begin to document, in near real time, the immediate and long-term effects of a catastrophic volcanic eruption. What they learned over the next few years laid the foundations for the modern science of volcanology. And it was an especially eye-opening lesson in how the biggest eruptions can influence climate, agriculture, and even the course of human history. 几天之内，这场灾难的源头便传遍了全球。1883年8月27日上午，一场火山爆发摧毁了爪哇岛和苏门答腊岛海峡中的两座岛屿，以及第三座岛屿的大部分。超过3.6万人丧生，其中大多数死于那场巨大爆炸引发的毁灭性海啸。得益于维多利亚时代的电信技术，这是历史上第一次全球民众能够近乎实时地记录一场灾难性火山爆发的直接和长期影响。他们在随后几年中学到的知识，为现代火山学奠定了基础。这也给人们上了一堂令人大开眼界的课，展示了大规模火山爆发如何影响气候、农业，甚至人类历史的进程。

Global effects

全球影响

In the months after Krakatau, drifting volcanic particles high in the atmosphere circled the globe, causing violently colored sunsets that contemporary artists captured in paintings, likely including the psychedelic background of Edvard Munch’s The Scream. But the key climate-driving component of the volcano’s emissions was sulfur from the molten rock that fed Krakatau. Once sulfur erupts into the atmosphere, it can form particles called aerosols that reflect sunlight and cool Earth. In the months and years after the eruption, average summer temperatures fell 0.6° Celsius (1.1° Fahrenheit) in the non-tropical regions of the Northern Hemisphere. 喀拉喀托火山爆发后的几个月里，漂浮在高层大气中的火山颗粒环绕全球，导致日落呈现出强烈的色彩，当时的艺术家们将其捕捉在画作中，其中很可能包括爱德华·蒙克名作《呐喊》中那迷幻的背景。但火山喷发物中影响气候的关键成分是来自供给喀拉喀托火山的熔岩中的硫。一旦硫喷入大气层，它就会形成被称为气溶胶的颗粒，这些颗粒能反射阳光并使地球降温。在火山爆发后的几个月和几年里，北半球非热带地区的夏季平均气温下降了0.6摄氏度（1.1华氏度）。

Fast-forward more than a century, and researchers now understand that climate changes, especially rapid ones, have transformed societies by affecting agriculture, public health, and living conditions. With what they’ve learned from Krakatau and other eruptions, volcanologists today are identifying past catastrophic blasts that may have contributed to historic events like droughts, famines, epidemics and societal unrest. “In so many different ways societies were affected … a failure in harvest or flooding or a cold summer or a really cold winter,” says Katrin Kleemann, an environmental historian at the German Maritime Museum in Bremerhaven. While they can’t prove an eruption caused the demise of a regime, volcanologists have uncovered some intriguing links, including some that could inform our understanding of how today’s society might react to a rapidly changing climate. 一个多世纪过去了，研究人员现在明白，气候变化，尤其是剧烈的气候变化，通过影响农业、公共卫生和生活条件改变了社会。利用从喀拉喀托火山和其他火山爆发中学到的知识，今天的火山学家正在识别过去可能导致干旱、饥荒、流行病和社会动荡等历史事件的灾难性喷发。“社会受到影响的方式多种多样……可能是歉收、洪水、凉爽的夏天或极寒的冬天，”德国不来梅哈芬德国航海博物馆的环境历史学家卡特琳·克莱曼（Katrin Kleemann）说。虽然他们无法证明某次火山爆发直接导致了某个政权的灭亡，但火山学家已经发现了一些有趣的联系，其中一些联系可以为我们理解当今社会如何应对快速变化的气候提供参考。

536 and all that

536年及相关事件

The first challenge in making volcano-society connections is to find physical fingerprints of past eruptions. In the year 536, scribes in Europe, the Middle East, and Asia wrote about bizarre weather, including a haze that shrouded the sun for 18 months. Temperatures plummeted, harvests failed, and within a few years, the first documented global plague began. These early medieval chronicles strongly suggest a major volcanic eruption—but the hard evidence lies deep in polar ice. Scientists can infer that big eruptions happened at certain times in the past by looking for sulfur and ash deposits in ice cores from Greenland and Antarctica. These cores, drilled into ice sheets, preserve an annual record of whatever was circulating in Earth’s atmosphere as it settled onto the surface each year. Researchers can read these frozen layers back in time like turning the pages of a book. It turns out that polar ice cores do contain large amounts of sulfur dating to 536, a distinct signal of a major eruption. But which volcano went off at the time remains a mystery. There is no known written record from anyone living close to the eruption—Iceland, where it may have occurred, was not yet populated. 建立火山与社会之间联系的首要挑战是找到过去火山爆发的物理指纹。在公元536年，欧洲、中东和亚洲的抄写员记录了奇怪的天气，包括一层笼罩太阳长达18个月的阴霾。气温骤降，农作物歉收，几年内，人类历史上第一次有记载的全球性瘟疫爆发了。这些中世纪早期的编年史强烈暗示了一次大规模的火山爆发——但确凿的证据深埋在极地冰层中。科学家可以通过寻找格陵兰岛和南极洲冰芯中的硫和灰烬沉积物，推断出过去特定时期发生的大规模喷发。这些钻入冰盖的冰芯，保存了每年沉降到地表的地球大气中物质的年度记录。研究人员可以像翻书一样，通过这些冰层回溯时间。事实证明，极地冰芯确实含有大量可追溯至536年的硫，这是大规模火山爆发的明显信号。但当时究竟是哪座火山喷发仍然是一个谜。目前没有发现任何生活在喷发地点附近的人留下的书面记录——当时可能发生喷发的冰岛尚未有人居住。

Empire falls

帝国陨落

There is better evidence pinpointing the volcano that may have helped topple the Mongol Empire seven centuries later. Until 2013, researchers knew only that some eruption—the biggest in the last few millennia as measured by sulfur output—occurred in 1257. In 2013, an interdisciplinary team radiocarbon-dated the ash, pumice, and other deposits around Samalas, a volcano in Indonesia, tying it to the 1257 eruption. Tree-ring studies, which analyze annual growth layers on trees to determine which years had good and bad growing weather, show extensive cooling across North America and Eurasia from 1257 to 1259. Among other impacts, bad harvests led to starvation. 七个世纪后，有更好的证据指向了可能导致蒙古帝国覆灭的火山。直到2013年，研究人员只知道1257年发生过一次火山喷发——按硫排放量计算，这是过去几千年来最大的一次。2013年，一个跨学科团队对印度尼西亚萨马拉斯（Samalas）火山周围的火山灰、浮石和其他沉积物进行了放射性碳测年，将其与1257年的喷发联系起来。树木年轮研究通过分析树木的年度生长层来确定哪些年份气候适宜生长，结果显示1257年至1259年间北美和欧亚大陆出现了大范围的降温。除了其他影响外，歉收还导致了饥荒。