January 06, 2007

The physical constraints of civilisation

The Granite Studio has in his normal fascinating way found a report from Nature which blames climate change for the fall of the Tang Dynasty in 10th Century China. The physical constraints on civilisations are seldom studied by historians. The great work on this kind of subject has to be Fernand Braudel's history of The Mediteranean in the age of Phillip II and other scholars like Felipe Fernandez-Armesto has provided a more modern attempt to delineate the ways that civilisations interract with their environment.

The thesis that the Tang fell because of climate change is a simplification. Political discord, migrations, economic trends and other human events probably influenced the fall of the Tang as much as environmental factors. Humanity is obviously dependant on its physical environs, its difficult to run a civilisation in some climates. It surely is no accident that it was on great riverbeds like the Nile, Indus, Tigris, Euphrates and Yellow River that the first civilisations developed. Its no accident that its proved exceptionally hard to maintain political authority in the central Eurasian plain- empires like Attila's and Genghis Khan's proved easy to conquer given the lack of physical barriers but also given the same factor swiftly fell apart. The lack of rivers running east-west as opposed to north-south made transport across Russia difficult for years so though the Urals in the 18th Century were producing as much iron as the UK, they couldn't export it because of the costs of transport. Physical barriers do influence history, they constrain what rulers and populations can do but they don't explain history. They don't explain for example why and when the Tang collapsed- but they explain why it was difficult for the Tang to govern at that point.

The Granite Studio has yet again highlighted something of great importance here. There is obviously a relationship between climate and the developments seen in history- but climate and physical environs represent constraints upon what humans can do, they don't explain it. Personally as a historian I find the human aspect most interesting- but that's just me. Global Warming could become a more terminal constraint than previous physical impositions upon human civilisation- though no doubt some kind of civilisation would survive and the form that would take would depend on the way that human ingenuity dealt with the crisis.

The physical shape that the world around a civilisation takes constrains the way that the civilisation can behave but doesn't predict its history.