An often overlooked, yet very important, environmental process in world history is known as the "Late Antique Little Ice Age," which took place during the 6th century A.D. across most of the Northern Hemisphere and received its name because it was shorter and less well-known than the Little Ice Age, which took place from the 16th-19th centuries. An examination of the written sources from the 6th century, along with archaeological and climatological information, reveals that the Late Antique Little Ice Age was a major event in world history that had long-lasting repercussions on numerous societies. Although it was not as long or as severe as the later Little Ice Age, the Late Antique Little Ice Age drastically impacted several advanced societies across the Northern Hemisphere, including in Europe, Central Asia, East Asia, and even North America. Perhaps the best-studied aspect of the Late Antique Little Ice Age is the role it played in the collapse of the Western Roman Empire and how it helped shape the composition of early medieval Europe. Some of these studies suggest that the Late Antique Little Ice Age played a major, if not the most important, role in the reformation of Western Europe after the fall of the Roman Empire. Other studies suggest that the Late Antique Little Ice Age affected the political structure of late ancient societies in the Middle East and Arabia, helping to give rise to Islam. And finally, although the Late Antique Little Ice Age's effects on East Asia and North America have not been studied nearly as much as its influence on Europe, the archaeological and some textual evidence – in the case of East Asia – suggest that the Late Antique Little Ice Age also affected how complex societies transitioned in those regions during the 6th century and later.
