Late Antique Little Ice Age


The Late Antique Little Ice Age was a long-lasting Northern Hemisphere cooling period in the 6th and 7th century AD, during the period known as late antiquity.

Description

The existence of a cooling period was proposed as a theory in 2015, and subsequently confirmed as the interval from 536 to about 660 AD. This period coincides with two to three immense volcanic eruptions in 536, 539/540 and 547. The 536 eruption is surmised to have been from a high-latitude volcano, such as in Alaska or Iceland. The 539/540 volcano is believed to have been Ilopango in present-day El Salvador. Another suspected volcanic site is the Rabaul caldera, in the western Pacific, which erupted around 540.
The extreme weather events of 535–536 were the early phenomena of the century-long global temperature decline. One study suggested a global cooling of 3.6F.
The evidence comes from a temperature reconstruction from the Euro-Med2k working group of the international PAGES project, using new tree-ring measurements from the Altai Mountains, which closely matches the temperatures in the Alps in the last two centuries. Additional ice cores from Greenland and Antarctica show increases in sulfate, a product of volcanic eruptions, at 536 and 539/540.

Regional impacts

Mesoamerica

It is theorized that the eruption of Ilopango and subsequent weather events and agricultural failures directly led to the abandonment of Teotihuacan by the original inhabitants.

Middle East

According to research by a team from the Swiss Federal Research Institute at Birmensdorf, the fall in temperatures led to the Arabian peninsula experiencing a dramatic increase in fertility. The boost of food supply contributed to the Arab expansion beyond the Arabian peninsula in the Islamic conquests. The cool period also led to increased strain on the Eastern Roman Empire and the Sassanid Persian Empire, hence easing the Muslim conquest of the Levant, the Muslim conquest of Egypt and the Muslim conquest of Persia.
According to research done by Israeli scientists, starting in 540, the size of the population of the city of Elusa in the Negev desert and the amount of garbage it generated shrank greatly. Elusa housed tens of thousands of people during its height. The major decline took place around the middle of the sixth century, about a century before the Islamic conquest. One possible explanation for the crisis was the Late Antique Little Ice Age.

Mediterranean region

The cooling period coincided with the Plague of Justinian, that began in 541, though the connection between the plague and the volcanoes still remains tenuous.
The cooling period contributed to the migrations of the Lombards and Slavs into Roman territory in Italy and the Balkans.