The 1200 Year Environmental Cycle Explained
Historians have long suspected that there was a 1200-year cycle in the rise and fall of cultures around the world. Although this blog has focused mainly on the Middle East and Europe, the 1200-year cycle has been noted in the Americas and Asia.
While the cycle itself does not always conform to the exact 1200-year pattern (that would be unnatural), it is close enough that we can compare the cyclical cultural changes with climactic change cycles that scientists speculate may occur every 1200-1500 years. This environmental cycle has not been formally proven; therefore some climatologists question the idea. Most climatologists accept that there was a very clear cycle prior to the end of the last glaciation period (about 15,000 years ago); opinions vary on whether that cycle continued into the current interglacial period (which continues today).
In 2005 S. Fred Singer and Dennis T. Avery argued that Earth passes through an “unstoppable” 1500-year cycle (it may vary up to 300 years, they say) of warming and cooling. Singer and Avery published their arguments in a book (Unstoppable Global Warming: Every 1,500 Years, Updated and Expanded Edition). Not everyone has been convinced by Singer and Avery’s arguments.
In 2009 Arizona-based climate scientist Zack Guido published a summary of climatological research about warming and cooling trends over the past few millions years. He noted some cyclical properties had been observed over the past 1200 years and included some other milestones that match up with the 1200-year cycle hypothesis.
In 2010 S. Fred Singer teamed up with Craig Loehle to present yet more evidence supporting the 1500-year argument. Singer’s work focuses on the timeline for Dansgaard-Oeschger (OD) events found in the Greenland ice cores timeline (extending back about 2 million years). The OD events occur about every 1500 years, in which sudden warming events take place in the climate. Singer acknowledges that the OD events are not always found at expected intervals — that sometimes the warming events do not happen. Similar cycles, called Bond Cycles, have been noted in oceanic sediments. Singer and his team devised a method for using proxy data to support his thesis.
In 2011 LiveScience covered a study published in The Holocene (download the original study here) by Julia Pongratz and others that documented a change in global CO2 levels coinciding with the Mongol invasions (Circa. 1200-1280 CE) of Europe and Asia. The study authors posit that the Mongol invasion may have been the cause or a significantly contributing factor to global cooling which eventually resulted in what has been called “The Little Ice Age” (lasting from about 1350 to 1850).
Climatologist Cliff Harris and Meteorologist Randy Mann have charted the 1200-1500 year cycle from about 2500 BCE projecting it out toward 2040 CE. They note a correlation between a decrease in both Solar activity and an increase in volcanic activity which seems to coincide with the cyclical mimima and maxima.
Although no one has yet shown that climactic change is directly responsible for widespread changes in cultural distribution, the evidence is mounting in favor of such cyclical events in human history. By looking for evidence of these cultural collapses at appropriate intervals historians and archaeologists may discover new insights into the past.
Of course, there is the danger that believing the cycle drove all human cultural change will create a bias in our interpretation of the past, which would undermine the value of continuing research. So while the hypothesis is an important conjecture it is only one of many that should be used to analyze patterns of human migration and cultural evolution.
That the Earth’s climate is pulsing every 1200-1500 years should not be doubted. This pulsing effect is a result of natural processes that drive both global warming and global cooling. Significant changes in environment will change how crops and animals grow, and obviously the human cultures that depend on those crops and animals will experience upheaval when their food sources are threatened.
According to a study published in 2014, substantial changes in climate around 15,000 years ago led to the great die off of Pleistocene megafauna — not human hunting. When the climate changed the plants at the bottom of the food chain began to die off. Scientists now believe that mammoths mostly ate flowering plants that vanished from their traditional grazing lands, and starved of food the mammoths died off. What killed the mammoths may also have killed other great animals and the predators that depended on them for food.
Humans were able to adapt by hunting new game, or developing agriculture. In fact, agriculture may have arisen as a result of climate change. And the rise of agriculture certainly signals a change in human culture of a great magnitude. What we may be on the verge of proving is that the Earth’s environmental cycle has had a greater impact on human civilization than previously imagined. Everything we accomplish on a global, cultural, and technological scale may have occurred in response to severe traumatic climate events that forced whole populations to do something or die.