The Roman Philosopher Lucius Anneaus Seneca (4 BCE-65 CE) was perhaps the first to note the universal trend that growth is slow but ruin is rapid. I call this tendency the "Seneca Effect."
Showing posts with label Garamantes. Show all posts
Showing posts with label Garamantes. Show all posts

Thursday, April 15, 2021

Saudi Arabia Goes the way of the Garamantes. Google Earth Confirms the Collapse of the Water Supply


In 2008, I noted the decline in Saudi Arabian water production and I published an article in "The Oil Drum" titled "Peak Water in Saudi Arabia." Using a simple version of the Hubbert model of resource depletion, I noted how the supply of "fossil water" had peaked in 1990 and had been declining ever since. This is the typical behavior of "fossil" resources: they tend to peak and then decline. It had already happened to the ancient Garamantes, inhabitants of central Sahara, who had developed sophisticated technologies of water extraction during the 1st millennium BC. That had allowed them to prosper for about one thousand years, but then depletion had its revenge and they vanished among the sand dunes. Something similar (but probably much faster) is going to happen in the Arabian peninsula. 


The old Hubbert model was developed to describe the cycle of extraction of crude oil. It may be oversimplified if you want to use it for detailed predictions. But, as a quick tool for understanding the situation of the production of a non renewable resource, it tells you a lot of what you need to know. That first stab of mine on water production in Saudi Arabia turned out to be correct. 

It is impressive how, today, you can use Google Earth to look at the situation "from above." You can see the collapse of the agricultural fields as depletion progresses. Here are the images of an irrigated area for a region East of Al Jubail, in Saudi Arabia,  26°48'29.60"N and  49° 8'47.58"E. 

Let's start with an image of the desert in 1984. There is absolutely nothing there:

One year later, 1985. Someone has started extracting water and irrigating the land. There are two active fields there. 

Below, you see an enlargement of the 1985 situation. Someone has built a road and you can see six irrigated areas, of which two are active. Each circle is almost exactly 1 km diameter. It is called "center pivot irrigation" -- there is a long arm that turns around the central pivot and irrigates the area.

Below, the situation in 1986 -- there are now 31 active circular fields. 

And now the area in 2002. There are now 46 active or partially active fields. Note the dark spots among the circular green areas. It is not clear what they are, could they be small ponds of brine? The water they are using probably has a high salinity and they have to dispose of it, somehow. 

 Below, the situation in 2015. The cultivated area is clearly declining. There are now only 17 active fields.


And, finally, the situation in 2020. It is gone. No green fields anymore. They simply ran out of water.

That doesn't mean that agriculture in Saudi Arabia is completely over. Scanning the desert using Google Earth, you can still find irrigated areas. Here is a place called Qariat al Olaya

There are several irrigated circles, but note the number of "ghost" fields, not irrigated anymore. It may be a seasonal effect, but it may well indicate big problems with water supply. 

Finally, some data about wheat production in Saudi Arabia, the most recent I could find (from "actualitix")

As you see, they had two peaks: the first one is the one I had already noted in my article on the "Oil Drum" of 2009. The second one was ca. 2005. As it often happens, when a resource starts declining, people tend to apply more capital to keep things going. It happens also with crude oil, the case of "shale oil" is a classic example. In Saudi Arabia, they succeeded in creating a second peak. But now, it seems to be the final decline. 

Just like the ancient Garamantes, the Saudi Arabians were able to overcome the aridity of their land by using fossil water. But when they ran out of it, it was time over for them. The Saudis still have crude oil and can import food despite not being able anymore to produce it. But oil is a fossil resource, subjected to depletion just like fossil water. And the destiny that befell the Garamantes is going to befall all those who depend on fossil resources. 


Friday, April 9, 2021

How Resource Depletion Leads to Collapse. The Story of a Lost Kingdom

The Garamantes were a North-African civilization that grew at the time of the Roman Empire. They were powerful enough that the Romans had to build a system of fortifications to defend their possessions on the coast. But the Garamantes ran out of their water resources and they faded, leaving little trace in history, except ruins, some graffiti on rocks, and a few lines written by ancient historians

The idea that a civilization may collapse because of resource depletion is often hard to believe for historians. They seem to believe that society is such a complex entity that it is impossible to find a single reason for it to collapse. And, yet, it is typical of complex systems that an external perturbation generates a cascade of feedback effects that may mask their origin and make it appear as a series of events had somehow cooperated to bring down the whole structure. But it is all the effect of that initial perturbation unbalancing the whole system: it is the straw that brought down the overloaded camel. This is the basic idea of what I call the "Seneca Collapse." 

The Garamantes were a classic case of a civilization that collapsed because they ran out of an unreplaceable resource: in this case, water. They were an interesting case of a society that had grown and prospered in a barren land, in the middle of the Sahara desert. 

But they were able to prosper by means of a sophisticated irrigation system. It is called the foggara technology in North Africa, in Persian it is kārēz and in Arabic Qanat(image from Wikipedia)

It is a sophisticated technology but it has a defect: it uses a non-renewable technology, fossil water. When the Garamantes started deploying these systems of wells and channels, around the last part of the 1st millennium BCE, it may be that the Sahara still contained relatively large underground aquifers inherited from the time when it had been green a lush with forests, about 10,000 years ago. (image source)
The water bonanza led the Garamantes to become a major regional power, enough to force the Romans to build fortifications to defend their coastal possessions and to use as starting points to launch raids into the Garamantes territory. Caesar fought and defeated them, while the last confrontation we know of was a military expedition launched by Emperor Septimius Severus, who is said to have captured the capital city of Garama in 202 AD. But the Romans never settled in that region.

In the end, the prosperity of the Garamantes was short-lived and they declined in parallel with the Roman empire, even though for different reasons. The story is described by David Keys in his article titled "Kingdom of the Sands." Clearly, Keys understands perfectly well how resource depletion takes down kingdoms and empires. It is not so much a question of running out of the resource. It is that you run out of the means to exploit it (in the case of the Garamantes, slaves).

In the end, depletion of easily mined fossil water sounded the death knell of the Garamantian kingdom. After extracting at least 30 billion gallons of water over some 600 years, the fourth-century A.D. Garamantes discovered that the water was literally running out. To deal with the problem, they would have needed to add more man-made underground tributaries to existing tunnels and dig additional deeper, much longer water-extraction tunnels. For that, they would have needed vastly more slaves than they had. The water difficulties must have led to food shortages, population reductions, and political instability (local defensive structures from this era may be evidence for political fragmentation). Conquering more territories and pulling in more slaves was therefore simply not militarily feasible. The magic equation between population and military and economic power on the one hand and slave-acquisition capability and water extraction on the other no longer balanced.

The desert kingdom declined and fractured into small chiefdoms and was absorbed into the emerging Islamic world. Like its more famous Roman neighbor, the once-great Saharan kingdom became, little by little, simply a thing of myth and memory. Along with the rest of the world, Berbers living in the Fazzan today have all but forgotten their ancestors. The kingdom's legacy has faded so dramatically that local residents believe the vast water-extraction system--the pride of the Garamantes--is the handiwork of Romans.

It seems that the city of Garama still existed when it was conquered by the Arabs, during the 7th century AD but, after that, there are no more records about it. 

It is curious how little is left of a kingdom that, once, was powerful enough to challenge the mighty Roman Empire. We have only fragments of knowledge of a civilization that was considered already remote and mysterious during classical times. Today, the Garamantes are mentioned by Jorge Luis Borges in his masterpiece "El Immortal" as people who "keep their women in common and nourish themselves with lions." The Garamantes are one of the civilizations you can choose to play in Sid Meier's Civilization V. And we have a few more snippets, including a recent novel (2018) that features an archaeological search in the former land of the Garamantes. I figure that if there existed a list of the worst novels in history, this one would make it to the top (that's why I don't give you the link, but if you like to harm yourself, ask me privately!)

And so it goes, civilizations grow, become powerful, then they are lost in the sand. That was the destiny of the Garamantes. What will be left of ours, well, it is all to be seen. But they say that humans always march toward the forest, leaving the desert at their back. And the Earth is round.