A period of pronounced cooling from about 536 to 660 CE coincided with a period of dramatic societal upheaval across Europe and Asia, reports a paper published online in Nature Geoscience this week. The authors term this cold interval Late Antique Little Ice Age.
During the sixth and seventh centuries, Europe and Asia saw massive societal struggles and changes, including the Justinian plague, the transformation of the Roman Empire, political change in China, the spread of Slavic-speaking people and the development of the early Arab-Islamic Empire.
Ulf Buntgen and colleagues used tree-ring-width measurements from the Russian Altai Mountains and the European Alps to show that this interval was unusually cool throughout Europe and Asia, relative to the rest of the past 2,000 years. They attribute the cooling to a series of large volcanic eruptions and their associated climate feedbacks, and suggest that this sudden cooling should be considered an environmental factor that contributed to crop failure and famine, as well as the aforementioned societal changes.
In an accompanying News & Views article, John Haldon writes, “In the case of the Late Antique Little Ice Age, we seem to have a pretty clear a priori case for assuming that a dramatic period of cooling, that can be dated reasonably precisely and that coincided with substantial societal change across a large part of the Earth’s surface, had a causal impact.”