In March of the year 536, the sky over Constantinople went dark for a year-and-a-half. The Roman historian Procopius wrote that "the sun gave forth its light without brightness… and it seemed exceedingly like the sun in eclipse." The statesman Cassiodorus described noon without shadows, a full moon "empty of splendour," and "a winter without storms, a spring without mildness, and a summer without heat." Michael the Syrian later recorded that the sun shone feebly for a year and a half. In China, a yellow ash-like substance fell from the sky, and snow fell in August. The volcanic winter of 536 was the most severe episode of climate cooling in the Northern Hemisphere in the last two thousand years.
The cause — unknown to anyone alive at the time — was at least three volcanic eruptions at still-uncertain locations, which pumped sulfate aerosols into the atmosphere and lowered European summer temperatures by as much as 2.5°C. Crops failed across the world; the Irish annals record "a failure of bread from AD 536–539"; a famine in China's Guanzhong region killed an estimated 70 to 80 percent of the population and led to cannibalism; and the Plague of Justinian followed. The eruptions kicked off the Late Antique Little Ice Age, which lasted until 660.
Historian Michael McCormick has called 536 "the beginning of one of the worst periods to be alive, if not the worst year."
Previously:
• A volcanic eruption unearthed a pair of sunken ships on Iwo Jima
