Why we should care climate change triggers civilization collapse

Arid landscape in the former Fertile Crescent area of south-west Syria. Image; Simone Riehl, Tübingen University.
Arid landscape in the former Fertile Crescent area of south-west Syria. Image; Simone Riehl, Tübingen University.

New research shows that many ancient civilizations collapsed because of climate change. So is history repeating itself?

Scientists looking at what is known as the Fertile Crescent of ancient Mesopotamia have found new evidence that drought caused by climate change brings an end to civilizations.

It is the latest study that confirms changes in rainfall patterns also poses a threat to present-day cities in Africa, Asia and parts of the United States. Droughts can lead to the abandonment of once-fertile areas and the cities that once were fed by them.

A team from Tübingen University, Germany, focussed its research on an area that is now part of Iraq and a number of countries in the Middle East where the development of ancient agriculture led to the rise of large cities.

Evidence from grain samples up to 12,000 years old shows that while there was good weather, fertile soil fertile and a well-managed irrigation system, the local population prospered. When rainfall became intermittent, agriculture collapsed and the cities were abandoned.

Analysed grains

Dr Simone Riehl, at the Senckenberg Center for Human Evolution and Palaeoenvironment at Tübingen University, analyzed grains of barley from 33 locations across the Fertile Crescent to determine if farmers had enough water to grow their crops.

The 1,037 ancient samples were compared with modern samples from 13 locations in area. They found that many settlements were hurt by drought and major climate fluctuations.

“Geographic factors and technologies introduced by humans played a big role and influenced societies’ options for development, as well as their particular ways of dealing with drought,” Riehl saidli.

Her findings indicate that harvests in coastal regions of the northern Levant, at the eastern end of the Mediterranean Sea, likely got enough rainfall. But further inland, drought led to irrigation or, in extreme cases, abandonment of the settlement.

The findings give archaeologists clues as to how early agricultural societies dealt with climate fluctuations and differing local environments.

The study is part of a project, backed by the German Research Foundation, looking into why ancient Near Eastern societies rose and fell.

Scientists carrying out similar research in the Indus Valley in present-day Pakistan and north-west India, home to the Harappan Civilisation, also believe that drought triggered the demise of that civilization.

The area has large, well-planned cities with advanced sanitation. But the Harappans seemed to slowly lose their urban cohesion and their cities were gradually abandoned.

According to a March article in Nature, a 200-year drought, caused by the failure of the monsoon, led to the abandonment of the cities.

The Mayan Mystery

Across the Atlantic, another puzzle was the loss of the Mayan cities and culture in Central America. This was a people that had the time, money and manpower to build massive temples and cities for a population of 13 million.

Theories abound as to why the Mayans abandoned their way of life over a period of about 200 years from 750 to 950AD. Research by Sigma Xi, the scientific research society, said that a series of droughts was the cause.

With the latest report of the Intergovernmental Panel on Climate Change predicting a faltering of the monsoon that is vital for the Indian sub-continent, it seems as though history could repeat itself. Certainly, some people in India believe it could happen unless action is taken to curb climate change.

Environmental refugees in Africa are also victims of changing weather and California is suffering a three-year drought that is drying up water supplies in one of America’s most prosperous states. – Climate News Network

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