Empires collapse not only from the invasion of barbarians or internecine wars for power. According to a number of studies, some advanced ancient societies have disappeared from the face of the Earth due to environmental problems - air pollution, deforestation and soil erosion.
Bronze Age Tillers
An international team of scientists examined hundreds of animal fossil bones found in Ireland, and came to the conclusion that biochemical cycles in the soil (including the nitrogen cycle) were disrupted as early as the Bronze Age, about three thousand years ago.
An excess of 15N nitrogen isotopes in bones indicates interference with natural human ecosystems. At the end of the Middle Bronze Age, the content of this substance in the soil rose sharply and never again dropped to its original values.
In the wild, nitrogen builds up in the soil and is removed from there constantly, providing balance. Ancient tillers, clearing forests, planting crops and raising livestock, upset this delicate balance and completely reshaped Ireland's soil ecosystems. According to the authors of the work, the results of the study can be extended to other regions of the world. It turns out that man began to change nature for himself several centuries earlier than previously thought.
Mayan deforested forests
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It was the violation of biochemical cycles and, as a consequence, soil depletion that contributed to the disappearance of the Mayan civilization, American and Canadian geologists are sure. Analysis of organic sediments from the bottom of lakes Chichankanab, Salpeten and Itzan in southern Mexico showed that the transformation of Mayan villages into the first large city-states was accompanied by intensive deforestation of tropical forests for arable land and, accordingly, soil degradation.
Scientists suggest that the soil of the jungle, where corn and other crops were planted, did not have time to recover, so the Indians had to destroy more and more trees and abandon old fields.
Deforested soils were destroyed, and some trace elements were washed out of them. These irreversible changes made the Mayan land infertile, resulting in famine and political instability. In the 9th century AD, people left most of the Mayan city-states.
Ruins of the city of Tulum on the Yucatan Peninsula, Mexico.
Idols instead of animals
A similar story happened on Easter Island. Due to the massive deforestation, wind and rain erosion of soils began, which is evident from an increase in the amount of metal ions washed out of the soil in sedimentary deposits. The consequences were not long in coming: raw materials dried up - wild forest edible plants, the productivity of cultivated cereals fell. Land birds have disappeared completely, and the species diversity of seabirds has decreased by almost three times. Lack of resources led to war between tribes, increased social inequality, the appearance of the famous stone moai statues and the mass extinction of the population.
Studies of the soil and foundations of the buildings remaining on the island have shown that when people inhabited it, the land was not a barren desert, there was a subtropical forest with tall trees and shrubs. Deforestation began, most likely around 900 AD. By the 20th century, there were only 48 plant species on the island, the largest of which, toromiro, is no higher than two meters. The rest is low ferns, grasses, sedges and shrubs.
As evolutionary biologist Jared Dimon notes in Collapse. Why do some societies lead to prosperity, while others lead to destruction?”The islanders did not have external enemies, as they were isolated and had practically no contact with anyone. There is also no evidence of climate change during this period. The disappearance of the moai culture is a purely ecological disaster, in which the inhabitants of Easter Island themselves are to blame.
Destruction of the green island
The Vikings, who colonized Greenland in the 10th century, unwisely consumed natural resources and thereby brought the death of their community closer. For a long time, it was believed that the descendants of Eric the Red left the island due to climate change. When the Vikings landed in Greenland in 986, the average annual temperatures in Europe were quite high. Four centuries later, the so-called Little Ice Age began, provoking famine and mass death of the population.
However, the analysis of samples from the Greenland glacier, carried out in 2015 by American scientists, led to the conclusion that no warming was observed in those places in the X-XIII centuries. It was as cold in the tenth century as it was in the fourteenth, when the last Vikings left the island. Therefore, the theory of a sharp climate change is hardly true.
Analysis of samples from the Greenland glacier, carried out in 2015, showed that the climatic optimum (an increase in average annual temperatures in Europe in the X-XIII centuries) did not affect Greenland.
According to Jared Daimon, the warlike Scandinavians have failed in Greenland due to a combination of several factors, but mainly due to the consumer attitude to natural resources. The study of lake bottom sediments showed that the Vikings burned forests for pasture for livestock, cut sod for construction and heating. The soils without vegetation were destroyed. The Scandinavian population of Greenland disappeared completely - thousands, exhausted by hunger, died in wars and riots, thousands left, and none of the descendants of Eric the Red remained.
Everything can be fixed
The described environmental problems are fatal for civilization only if the population does not want to adapt to changing conditions. The Vikings Daimon contrasts with the Inuit who lived in Greenland at the same time. They built their houses from snow and ice, heated themselves with the subcutaneous fat of seals, and ate mainly fish and sea animals.
According to zooarchaeologists, the ancient Egyptians contributed to the disappearance of wild animals in the Nile Valley, but managed to adapt to this, increasing the proportion of cereals in the diet. As researchers from the University of California at Santa Cruz, the Universities of São Paulo and Bristol have found, over the past four thousand years, out of 37 large mammals that lived in Ancient Egypt, only seven have survived to this day.
Scientists emphasize that now the ecological situation in the Nile Valley is especially unstable and it is very easy to disturb it. The loss of one or two species of animals can provoke a new ecological disaster.
Alfiya Enikeeva