Mayans and the Medieval Warming Period

I went to see Apocalypto over the weekend, and was reminded that the Mayan civilization flourished and died with the Medieval Warming Period. The degenerate Mayans portrayed in Gibson`s movie represented the last gasp of a culture that had been dying for quite some time, and their fate was linked to the environmental changes caused by the MWP and subsequent cooling period (contrary to what our friends at RealClimate may claim.)

Here is a chronology of historical/geological events by Professor of Earth Sciences James Aber which helps to illustrate the effects of the MWP and LIA. He mentions the collapse of Mayan culture several times, and links it to climate change resulting from the MWP.

This is a good timeline, but he fails to mention a number of other examples; the Mongols had been a collection of tent-dwelling nomads in the Gobi until the 13th Century when they exploded outword. Why? Because their food supply had greatly increased in the 12th Century thanks to a warming of their climate.

The Mississippian culture, called the Moundbuilders because they constructed artificial hills on which to build their temples rather than pyramids as the Aztec and Mayan civilizations preferred, flourished from between 800 and 1500 when they seemed to dwindle away to nothing. Suggestive, no? They seem to have followed a path similar to their Mayan neighbors.

In fact, the Spanish found all of the great kingdoms of the New World easy pickings because they were all in decline at the same time. The Incans were in the throes of a civil war, with two Sun-Gods claiming the throne, the Mayans were in the final stages of collapse, and the Aztec culture was buffeted by misfortune. Now, why should all of these kingdoms suffer this fate at this same time? Because agriculture soured as a result of changes in their climate, that`s why.

The Vikings are used by Dr. Aber, but not a lot of mentio is made of the Russians, who quietly began expanding into the Laplander territory to the north and into Asia. Game had become more plentiful and the Russian people sought to escape the ravages of the Golden Horde, so they began pioneering what had been sparsely inhabited lands.

Another example which Dr. Aber could have used was the Black Death. Bubonic plague was carried by a species of rat which immigrated from the steppes of Europe. It hit Europe in 1347 and wiped out fully a quarter of the population. There were two reasons for the arrival of the Plague; increased travel as a result of the warmer climate by Europeans and an increase in the rat population because of a greater food supply. Both of these illustrate that the world climate had warmed.

(An interesting side-note; the children`s rhyme ``Ring around the Rosie`` was about the Black Death. Rosie was a shortening of Rosary, meaning everyone was praying nonstop for the dead, posies and other flowers were often inserted in the pockets of the dead before burial. I think you`ll get the rest!)

This pandemic was ended with the arrival of a newer rat species from Asia, one which, while capable of carrying the Plague, avoided human contact. These newbies killed or chased off their rivals, thus ending the devastation. These, too, were driven by environmental forces.

The fact is, something drove tremendous changes in culture worldwide throughout the Middle-Ages, something which gave birth to new civilizations and destroyed older, less vital ones. It affected agriculture, health, and population patterns. If the Global Warming crowd has a credible alternative explanation, I`d like to hear it! A worldwide warming explains these events nicely.

Here is a piece which tells of a warm spell in 1540 so bad the Rhine dried up. No MWP?

So the next time some member of the Gang Green disputes the existence of the Medieval Warming Period, tell them to see Apocalypto!