Egypt is the starkest example of this with the Nile being a bright green strip in the middle of the Sahara and basically every Egyptian living there. But the others are also surrounded by desert or arid landscape on at least some of their path to the ocean. Tigris and Euphrates is surrounded by the Syrian and Arab deserts once it leaves Anatolia. Yellow River partially flows through the Gobi Desert. Indus flows through the Thar Desert and the Iranian Plateau.
Did the desert offer an early barrier to foreign enemies and give these people a breathing space to develop their civilization? Or is this just a coincidence?
I’d recommend checking out the top comment of this post. It’s important to remember that these regions didn’t always look as they do today, even just a few thousand years ago. For example, the Persian Gulf used to extend much further into Iraq. Aridification forces people to huddle up along the fertile river banks. Large populations and limited land available leads to urbanization.
I honestly never thought I’d see a question so closely linked to my thesis topic, so I do welcome the chance to go over some of the literature covering commonalities between early states.
I want to give two caveats before I go through my answer. Firstly, my knowledge background concerns economics and sociology literature. I can’t comment on the specific historical record of these civilisations, I can only comment on the trend you’ve noted and some high-level history. Secondly, I’m going to be nit-picky and instead focus on the history of states (aka empires/kingdoms) in those areas to avoid wading into the question of what is ‘a civilisation’.
Tldr – you’re exactly right in the pattern you observed,it’s a theory called environmental circumscription. However, your logic is backwards, deserts didn’t protect, rather they trapped communities and forced them to fall under an overlord.
Note on States
I want to flip the core pattern you identify in your question; your argument is that if left alone (let’s say from external threats) a group of people will develop and achieve greater heights (let’s say building more stuff or less tangible things like writing). I would argue that the argument should be flipped, that deserts contained groups of people and created an environment that satisfied the preconditions for more sophisticated states/civilisations to emerge.
I want to start by saying that states (or nations as they are in the present form) are not natural creations, they are structures of hierarchies and rely on coercion in order to actually apply power (i.e. enforce laws or extract tax/tribute). For states in Egypt, Sumer, Indus Valley or northern China to form at some point one community had to a) conquer another community and b) control them long term. After these two preconditions, they can form something greater than just a city-state (i.e. Egypt spreading all along the Nile). Out of the two conditions, it’s the controlling aspect that was more difficult as there was little stopping a conquered community from just upping and leaving somewhere else. There isn’t much incentive to remain under an overlord who limits your freedoms and charges tax/tribute when you can leave to another equally fertile area. Therefore, there needs to be some other force that enables the overlord/ruler to maintain control over multiple communities.
Role of deserts
As you identify a common element between these areas is the presence of deserts. Rather than protecting these areas from outside threats they actually did the opposite, they trapped people and communities in the area(environmental circumscription). There have been a few different ways to look at this. Firstly, sociologists like Michael Mann or Robert Carneiro depict this situation as being akin to a cage. A permanent state forms when it has formed a sufficiently strong set of pull factors to force people to remain – there are no outside options for communities other than to accept an overlord. The circumscription by deserts is an environmental cage that blocks off escape routes in the same way that more developed urban environments eventually discourage leaving to go somewhere else.
Secondly, a more economic view has been looking at incentives. The reality is that when living in Mesopotamia or Egypt, it made sense to remain where you were even if you had to pay tribute. The important factor being that the relative difference in fertility between the area around the river (lets say the Nile) and the desert. That is to say, you can generate a surplus of food if you stay by the river but you can’t if you choose to flee and live in the desert. This relatively is the key factor as opposed to the absolute fertility of these regions. Circumscription, whether it be through deserts or mountains creates that relativity.
An Exception
I wanted to finish up by touching on some exceptions or using these theories to explain why in some places it was more difficult to form states akin to those in Egypt for example. For example, in the Amazon, there was a lack of circumscription which inhibited any large state formation and meant wars were fought for prestige rather than land (as rulers could not conquer territory as they lacked the power to stop conquered communities from fleeing).
Final Comments
I’m happy to answer any further questions or clarifications f there are any. I can also touch on other theories that have tried to explain why civilisations/states emerged and why this theory attracts the greatest consensus.
References
Carneiro, Robert L. (1970): A Theory of the Originof the State. Science, 169, 733–738.
Mann, Michael (1986): The Sources of Social Power:A History of Power from the Beginning to AD 1760, volume I.
Schönholzer, David (2017): The Origin of the State:Incentive Compatible Extraction under Environmental Circumscription. Availableat SSRN: https://ssrn.com/abstract=2944106 or http://dx.doi.org/10.2139/ssrn.2944106.
