Climate Changes of Long Ago

A former neighbor dismissed concerns about climate change, saying this warming trend is just another of the climate shifts that occur naturally from time to time. He was right about long-ago climate changes and wrong about the cause of this one. What intrigues me, though, is the assumption that if today’s climate change were of natural origin, it would give no cause for concern.

Thriving Bronze Age cultures of the Mediterranean world—Egypt, Canaan, Crete, Mycenaean Greece, and the Hittite Empire of Asia Minor—disintegrated rather suddenly in the century after about 1200 BCE. Analysis of fossilized pollen reveals a severe drought throughout the region. Famine led to upheaval, mass migrations, attacks by “sea peoples,” disruption of trade, abandonment of Greek and Hittite writing systems, destruction of palaces and cities, dispersal into small rural settlements, and the fall of Troy.

Fast forward through the rise and fall of Rome and beyond. Vikings from Scandinavia raided and settled in Scotland, Ireland, northwestern France, and even southern Italy. They settled Iceland, previously uninhabited except for a few Irish monks, and southern Greenland, separate from the Inuit in the north. After about 1300, with the end of the “medieval warm period,” icebergs made trade with mainland Europe treacherous. Unable reliably to exchange trade walrus tusk for essentials like grain, Norse Greenlanders either left or died out. Iceland survived, but barely.

History gives no reason to suppose climate change is benign to humans so long as humans didn’t cause it. In fact, human-caused climate change could potentially have one advantage. Unlike the natural disasters of past millennia, those caused by humans might potentially be resolved by humans, if we could summon the political will to do so.

Image: Kerstiaen de Keuninck, (c. 1561-1635), Fire of Troy, Hermitage Museum, St. Petersburg.