Volcanic eruptions impact climate, subtly and profoundly. The size of an eruption is only loosely correlated with the severity of its climate effects, which can include changes in surface temperature, ozone levels, stratospheric dynamics, precipitation, and ocean circulation. We review the processes—in magma chambers, eruption columns, and the oceans, biosphere, and atmosphere—that mediate the climate response to an eruption. A complex relationship between eruption size, style, duration, and the subsequent severity of the climate response emerges. We advocate for a new, consistent metric, the Volcano-Climate Index, to categorize climate response to eruptions independent of eruption properties and spanning the full range of volcanic activity, from brief explosive eruptions to long-lasting flood basalts. A consistent metric for categorizing the climate response to eruptions that differ in size, style, and duration is critical for establishing the relationshipbetween the severity and the frequency of such responses aiding hazard assessments, and furthering understanding of volcanic impacts on climate on timescales of years to millions of years. ▪ We review the processes driving the rocky relationship between eruption size and climate response and propose a Volcano-Climate Index. ▪ Volcanic eruptions perturb Earth's climate on a range of timescales, with key open questions regarding how processes in the magmatic system, eruption column, and atmosphere shape the climate response to volcanism. ▪ A Volcano-Climate Index will provide information on the volcano-climate severity-frequency distribution, analogous to earthquake hazards. ▪ Understanding of the frequency of specific levels of volcanic climate effects will aid hazard assessments, planning, and mitigation of societal impacts.

中文翻译：

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考虑火山喷发规模与气候响应之间的不稳定关系：建立火山气候指数

火山爆发微妙而深刻地影响着气候。喷发的规模与其气候影响的严重程度只有松散的相关性，其中包括地表温度、臭氧水平、平流层动力学、降水和海洋环流的变化。我们回顾了岩浆房、喷发柱以及海洋、生物圈和大气中调节火山喷发气候反应的过程。喷发规模、类型、持续时间和随后的气候反应严重程度之间出现了复杂的关系。我们主张采用一种新的、一致的指标，即火山气候指数，对火山喷发的气候响应进行分类，与喷发特性无关，并涵盖从短暂的爆炸性喷发到持久的溢流玄武岩的全方位火山活动。对不同规模、类型和持续时间的火山喷发的气候反应进行分类的一致指标对于建立此类反应的严重性和频率之间的关系至关重要，有助于危害评估，并进一步了解火山在数年时间尺度上对气候的影响数百万年。 ▪ 我们回顾了火山喷发规模与气候响应之间的不稳定关系的驱动过程，并提出了火山-气候指数。 ▪ 火山喷发在一系列时间尺度上扰乱地球气候，其中的关键悬而未决的问题是岩浆系统、喷发柱和大气中的过程如何影响气候对火山活动的反应。 ▪ 火山气候指数将提供有关火山气候严重程度频率分布的信息，类似于地震灾害。 ▪ 了解火山气候影响特定水平的频率将有助于危害评估、规划和减轻社会影响。