Why is 536 called the worst year to be alive?

The phrase comes from medieval historian Michael McCormick of Harvard, who named 536 as the worst year to be alive. A mysterious fog dimmed the sun across Europe, the Middle East and parts of Asia for about 18 months, summers turned cold, crops failed, and famine followed. Plague arrived a few years later. McCormick himself hedged slightly, calling it the start of one of the worst periods to be alive, if not the worst year (see [science.org](https://www.science.org/content/article/why-536-was-worst-year-be-alive)). [1]

The Byzantine historian Procopius wrote that the sun gave its light without brightness, like the moon, during the whole year. Summer temperatures fell by 1.5 to 2.5°C, starting the coldest decade of the past 2300 years. Snow fell in China in summer, and an Irish chronicle records a failure of bread from 536 to 539. Historian Miles Pattenden adds that hunger and local conflicts left survivors more vulnerable to disease. Tree rings are one of the tools that show the cold, since a climate shock or eruption leaves a year of much reduced growth. [1] [2]

In 541 bubonic plague reached the Roman port of Pelusium in Egypt. This Plague of Justinian is said by McCormick to have wiped out one-third to one-half of the population of the eastern Roman Empire and to have hastened its collapse. Another account puts the toll at around a third of the Byzantine population. Pattenden describes a feedback loop in which one catastrophe in the pre-modern world often leads to others. The Harvard and Maine team reported that economic stagnation in Europe lasted until about 640, when a spike in airborne lead in the ice marks a revival of silver mining. The Conversation article also mentions drought in Peru's Moche culture and a continued cooling for more than a century. [1] [2] [3]

Most accounts agree that a volcanic veil caused the cooling, but the location is unsettled. In 2015 a team led by Michael Sigl matched polar ice cores with tree rings and found a large eruption in late 535 or early 536, followed by another in 540, and suggested North America as a possible source. In 2018 McCormick and Paul Mayewski's team analysed a Swiss glacier core and found volcanic glass in spring 536 ice whose chemistry matched particles from European lakes and bogs and a Greenland core, which resembled Icelandic rocks. David Lowe found this convincing, but Sigl said he needed more evidence before preferring Iceland over North America. Pattenden says there may have been up to three eruptions, near the equator or in Iceland. [1] [2]

The title is a judgement, not a measurement. The Conversation calls 536 the current consensus candidate for worst year, but cautions that historians over-rely on doom-laden quotes from writers such as Procopius and Cassiodorus. Its authors suggest most people may only gradually have realised how bad things were, and that the worst moment may have come after 536, once plague, drought and famine had fully set in. McCormick's own comparison is with years such as 1349 and 1918. [3] [1]