Sumerians are known as the founders of the urban civilization that dominated in southern Mesopotamia in the 4th and 3rd millennia BC. They developed a network of irrigation channels that made it possible to cultivate cereals in desert areas of the Lower Euphrates, introduced an ideographic script, initially pictographic and then simplified to the form of cuneiform characters impressed in wet clay, built the biggest cities in the world at that time, with monumental temples and enormous palaces.
Despite substantial evidence on the short-term effects of adverse climate shocks, our understanding of their long-term impact is limited. To address such a key issue, research has focused on ancient societies because of their limited economic complexity and their unparalleled experience of environmental and institutional change. Notably, ‘Collapse Archaeology’ literature has reported statistical evidence consistent with the mantra that severe droughts trigger institutional crises. This view, however, has recently been challenged by literature summarized in the paper Climate Change and State Evolution by Giacomo Benati and Carmine Guerriero.
Kings of Mari controlled an important trade route in the valley of the Euphrates River in the 3rd and early 2nd millennium BCE. Although their country was situated in an area with unfavourable conditions for agriculture, the economy of the kingdom of Mari could support a big population. The key to understanding this paradox is animal dung.
The kingdom of Mari was the most powerful country of north Mesopotamia in the 3rd and early 2nd millennium BC. Its power is reflected both by the size of its capital (modern archaeological site of Tell Hariri), which occupied an area of more than 60 hectares – more than Cracow in the 13th century – and by the fact that six of its rulers were included in the Sumerian King List, that is a record of the dynasties that were regarded as those holding superior power in Sumer. The dynasty from Mari was the only dynasty from north Mesopotamia on this list.