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Don Reicosky: Civilizations come and go based on food production and soil protection

Reading the headlines "Good progress against wildfire," "Heat wave hits state," "Heat storm," and the wilted corn and soybean crops in Minnesota raises a weather concern. More extreme weather and it's impacts on crop production lead to concerns about food security and sustainability. A visit to the Mayan exhibition, "Maya: Hidden Worlds Revealed" at the Science Museum of Minnesota was an "eye-opener" that provided information on the Mayan civilizations. This exhibition is an excellent example of historical lessons for our advanced society dependent on food security in view of extreme climate events. If we do not learn from history, history will repeat itself!

The Mayan people were considered an advanced civilization that excelled at agriculture, pottery, hieroglyph writing, calendar-making and mathematics, and left behind an astonishing amount of impressive architecture and symbolic artwork. The Mayans were good agrarians with corn as their staple crop. Some Mayans used slash and burn techniques. One theory has it that the Maya relied on slash-and-burn agriculture while another group says such methods couldn't have sustained the population at its peak. The researchers think the Maya also exploited seasonal wetlands, which make up more than 40 percent of landscape. Other Mayans used bench terraces on sloping land in an effort to reduce erosion with limited success.

Civilizations and soil erosion

History is a parade of civilizations that have arisen and then vanished. David Montgomery's 2007 book, "Dirt, The Erosion of Civilizations," explains the effect of poor soil management on several past civilizations. Many thriving civilizations collapsed due to erosion, salinization, nutrient depletion and other types of soil degradation. Soil erosion is the "canary in the coal mine" of food security. Montgomery states: "Whereas the effects of soil erosion can be temporarily offset with fertilizers and in some cases irrigation, the long-term productivity of the land cannot be maintained in the face of reduced soil organic matter, depleted soil biota, and thinning soil that so far have characterized industrial agriculture. Many factors may contribute to ending a civilization, but an adequate supply of fertile soil is necessary to sustain one."

The Mayan climate was studied by an international research team led by Douglas Kennett, PSU, (Science, November, 2012) who produced a climate record of Maya times: a sub annual reconstruction of rainfall in the Maya heartland back 2,000 years. Comparing this reconstruction to records of major Maya building episodes and warfare, they concluded that "an extended period of generous rainfall helped spur the growth and proliferation of Maya city-states. This was followed by an extended drought between A.D. 1020 and 1100 that likely corresponded with crop failures, death, famine, migration and, ultimately, the collapse of the Maya population." This history lesson is sadly similar to our "dust bowl days of the early 30s" in the US Great Plains.

What is our civilization's future?

For many civilizations, small climate change effects with the associated soil erosion limited the food supply and many civilizations either moved or perished. Should we be worried our civilization is about to go the same direction? Ensuring food security requires us to take the long view -- 40 to 50 generations -- to set a course now that stretches for future generations.

While the specific cause for the Mayan collapse is still being investigated, there is agreement on the four major problems that came together causing the collapse; warring nations, deforestation/erosion, climate change/drought and overpopulation. By learning what the Maya did right and what they did wrong, maybe we can help our people find sustainable ways to farm the land while stopping soil degradation that doomed the Maya. The question is, is anyone ready to listen to the historical lessons of previous civilizations on our continent?