War, Pestilence, Famine: That's Climate Change ... When It's Cold

We’ve been warned that man-made global warming will cause unprecedented turmoil within and among the Earth’s human societies. Yet the Earth’s history over the past 2,000 years shows that wars, disease epidemics, and famine were all far more likely when the Earth’s climate was cold.

Equally interesting? The war-likely periods occurred in cycles -- clearly tied to the temperature variations during the cold phase of the solar-linked 1,500-year climate cycle.

When an agricultural society suffers cold and cloudy summers, early frosts, and more crop-destroying hailstorms and floods, food production is severely hampered. When food production is reduced year after year, it impacts population numbers through starvation, disease, and warfare.

David Zhang at the University of Hong Kong writes that China’s three historic “peak war clusters” all occurred during cold periods. As did all seven periods of Chinese nationwide social unrest, and nearly 90 percent of changes in its imperial dynasties.

The “peak war” problem impacted both Europe and China during the same cold climate periods -- though the two regions were completely separate.

Zhang’s team notes the “General Crisis” of the Earth’s 17th century: The Thirty Years War (1618 to 1648) occurred while nearly every European country had massive crop destruction, famine, and disease. Elsewhere around the globe, internal revolts spread through the Ottoman Empire in the Middle East. Berbers fought Arab immigrants in Mauritania. The Shimabara peasant rebellion occurred in Japan, and the Ming Dynasty collapsed in China.

Earlier, a similar global cold period saw Mediterranean temperatures drop about 1.5 degrees C after 1250 BC. The Mycenaean culture collapsed in Greece, along with the Hittite Empire in the Fertile Crescent and the Harappan culture in the Indus Valley of India. China lost another dynasty, as the Zhou replaced the Shang.

Can such widespread violence and suffering really be tied to weather? Famine speaks for itself.