Perhaps I will get back to the next installment of "Back of the Envelope Geopolitics" soon. Indeed, the post is written - was written quite quickly as it should have been given the premise. However, this is the internet, and I feel the need to provide actual links.
I will occupy your interest today with a very quick point on map reading for political understanding:
Follow the water.
In general, people downstream are at the mercy of the folks upstream when it comes to a whole spate of environmental concerns. Not only pollution, but the carrying capacity of the land is directly impacted (fresh water and agriculture).
People upstream are generally at the mercy of the folks downstream when it comes to some forms of access to the wider world.
Think of Ethiopia and its hostility to Eritrea. Think of Turkey and Iraq and their mutual enmity. Think of Central Asia.
Posted by Martial