ENVIRONMENT

The Veiled Sun

536 CE

History · Middle Ages · Holocene · Meghalayan

In 536 CE the sun dimmed for many months; Byzantine witnesses wrote that it shone like the moon. Tree rings and ice cores identify the cause, a great volcanic eruption, followed by others in 540 and 547, which together opened more than a century of hemispheric cooling. Harvests failed under the veil, and within five years the Justinianic plague was killing across the same weakened world; empires from Rome's heir to Sasanian Persia entered the crisis together.

Why it matters

536 has been called the worst year to be alive, and its science is the point: an event known for fifteen centuries only through chronicles is now read annually in wood and ice, eruption by eruption. It is the cleanest ancient case of a volcanic climate shock interleaving with pandemic and politics, the same braid that runs through this timeline from the 4.2 ka drought to Tambora, and a reminder that the sky can change history in a season.

Dating & uncertainty

Tree rings across the Northern Hemisphere record the sharpest cooling between mid-July and early August 536; eruptions in 536, 540 and 547, sustained by ocean and sea-ice feedbacks and a solar minimum, opened a cold phase now called the Late Antique Little Ice Age, running to about 660. Wood anatomy finds little trace in the Southern Hemisphere: the veil was not evenly global.

Sources

1. Büntgen et al. (2016), Nature Geoscience · Cooling and societal change during the Late Antique Little Ice Age from 536 to around 660 ADdoi:10.1038/ngeo2652
2. Büntgen et al. (2022), Science Bulletin · Global wood anatomical perspective on the onset of the Late Antique Little Ice Age (LALIA) in the mid-6th century CEdoi:10.1016/j.scib.2022.10.019
3. Helama et al. (2018), Scientific Reports · Volcanic dust veils from sixth century tree-ring isotopes linked to reduced irradiance, primary production and human healthdoi:10.1038/s41598-018-19760-w

Our species’ history as one day

23:53:116 min 49 s before midnight

if the 315,000 years of Homo sapiens were compressed into a single day