Medieval accounts of eclipses shine light on massive volcanic eruptions

中世纪关于月食的记载揭示了大规模的火山爆发

Descriptions of lunar eclipses by monks and other scholars help scientists to pinpoint effects of ancient eruptions.

修道士和其他学者对月食的描述有助于科学家确定古代火山爆发的影响。

Jeff Tollefson（作者）

The great Japanese poet Fujiwara no Teika wrote in his diary of an unusually long and dark lunar eclipse in December 1229, observing that it was as if the Moon had entirely “disappeared”. Now climatologists have used Teika’s account and dozens of other lunar observations made by medieval scholars, clerics and monks to help pin down the timing and impact of volcanic eruptions from 1100 to 1300.

日本伟大的诗人藤原定家在1229年12月的一次异常漫长而黑暗的月食日记中写道，月亮似乎完全“消失”了。现在，气候学家利用藤原定家的描述和中世纪学者、神职人员和修道士进行的数十次其他月球观测，帮助确定1100年至1300年火山爆发的时间和影响。

The research, published in Nature on 5 April, corroborates data extracted from ice cores and could help scientists to understand the run-up to the cold period known as the Little Ice Age, as well as the effects of a controversial technique proposed for manipulating the climate.

这项研究于4月5日发表在《自然》杂志上，证实了从冰芯中提取的数据，并有助于科学家了解被称为小冰河期的寒冷时期的前期，以及一种有争议的操纵气候技术的影响。【这里指太阳能辐射管理技术（SDR）】

“If we really want to understand how past volcanic eruptions have impacted climate and societies, I think we need to combine historical archives, where they are available, with ice cores and tree rings,” says Sébastien Guillet, a palaeoclimatologist at the University of Geneva, Switzerland, and a co-author of the study. “None of these methods can work alone.”

“如果我们真的想要了解曾经的火山爆发是怎样影响气候和社会的，我认为我们需要将能找到的历史档案和冰芯与年轮结合起来，” 瑞士日内瓦大学的古气候学家、该研究的合著者Sébastien Guillet说。“这些方法中没有一个能够单独奏效。”

Dark Moon rising

晦月升起

The authors identified nearly 400 accounts documenting a total of 119 lunar eclipses. Of those, 37 included information about Moon colouration and darkness; scientists can use both traits to determine whether and to what extent a volcanic haze was present at the time.

作者找到了近400个文献记录，总共119次月食。其中37条包括关于月球颜色和晦暗的信息；科学家可以利用这两个特征来确定当时是否存在火山灰以及火山灰的范围。

The team documented six dark lunar eclipses, which are indicative of massive eruptions that pushed volcanic aerosols high into the stratosphere, which starts roughly 10 kilometres above Earth’s surface. By combining those accounts with model simulations, modern satellite observations and tree-ring data, the team estimated that the eruptions took place 3 to 20 months before the observations were made. The team identified another five reddish eclipses indicative of eruptions that injected aerosols into the layer below the stratosphere; these aerosols would have had a relatively small impact on the climate.

该团队记录了六次月食，这表明大规模爆发将火山气溶胶推高到平流层，平流层始于地表上空10km处。通过将这些描述与模型模拟、现代卫星监测和树木年轮数据相结合，该团队估计火山爆发发生在观测前3到20个月。该团队发现了另外五次淡红色的月食，这表明喷发将气溶胶释放到平流层以下的大气；这些气溶胶对环境影响相对较小。

Dust on ice

静滞的灰尘

The new record aligns with earlier estimates based on dust layers found in ice cores from Antarctica and Greenland. Seeing an independent record confirm the ice-core chronology “is very comforting”, says Elsa Gautier, a glaciologist at the University of Grenoble Alpes, France, who co-authored the analysis of the Antarctic cores.

这一新记录与之前基于南极洲和格陵兰岛冰芯中发现的尘埃层的估计一致。法国格勒诺布尔-阿尔卑斯大学的冰川学家Elsa Gautier说，看到一份独立的记录证实了冰芯年表 “非常令人欣慰”，她是南极冰芯分析的合著者。

The work could also further scientists’ understanding of the climate in 1100–1300, which could be key to understanding the development of the exceptionally cold period that followed, called the Little Ice Age.

这项工作还可以进一步加深科学家对1100年至1300年气候的了解，这可能是了解随后异常寒冷时期（即小冰河时期）发展的关键。

Knowing more about what happened in the past could also help to clarify the potential impacts of a controversial proposal known as solar geoengineering, in which particles would be injected into the stratosphere to reflect sunlight back into space. Some scientist argue that such efforts could serve as an emergency backstop to cool the planet and avert the worst effects of runaway global warming.

了解更多关于过去发生的事件也能够帮助澄清被称为太阳能地质工程的有争议提议的潜在影响，在该提议中微粒被释放到平流层，使阳光反射回宇宙中。一些科学家表示这样的成就能够作为一种应急措施，为地球降温，避免全球变暖的失控对地球造成最坏的影响。

“Volcanic eruptions are our only — albeit imperfect — analogue for how the Earth’s climate might respond to future solar geoengineering,” says Kevin Anchukaitis, a palaeoclimatologist at the University of Arizona in Tucson. Understanding the precise timing of eruptions can help scientists to improve their models, he says, and “better models should lead to a better understanding of the benefits and risks of geoengineering”.

“火山爆发或许是我们唯一能模拟未来太阳能地质工程对地球气候影响的方式——尽管不够完美，” 图森亚利桑那大学的古气候学家Kevin Anchukaitis说。了解火山爆发的确切时间可以帮助科学家改进他们的模型，他说，“更精确的模型应该能更好地理解地质工程的好处和风险”。

For Guillet, who spent a decade poring over historical records in his free time before finishing the project during pandemic lockdowns, the study is also a nod to the medieval observers whose accounts historians have long used to document social and political trends. “If they are able to provide such an accurate record about social and political events, why not about natural events?” he says.

Guillet在完成该项目和疫情封锁之前，曾花了十年的空闲时间仔细研究历史记录，对他来说，这项研究也是对中世纪历史学家的致敬，他们长期以来一直记录社会和政治倾向。“如果他们能够提供如此准确的社会和政治事件记录，为什么不提供自然事件呢？”他说。

doi: https://doi.org/10.1038/d41586-023-00939-9

（本文仅用于学习英语，并未用于其他用途）

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