In the third part of a three part series about the fall of the Roman Empire, Bret Devereaux discusses how the standards of living and agricultural productivity fell. Although people had not forgotten Roman technology, the collapse of trade in the former western Roman Empire changed production patterns. Different regions had formerly specialized in different crops. They sold their surpluses and bought what they didn’t produce. When they were not allowed to trade, they had to be self sufficient, meaning that they had to grow crops that weren’t as well suited to local conditions. This lead to lower overall yields. It was not a technical failure what caused a decline in living standards, but the failure of institutions that made trade possible.
I can think of more recent examples of interplay between technology and institutions. I used to work in bridge maintenance. One typical problem that we faced is that steel reinforcement of concrete bridges exposed to salty environments will corrode over time. This happens because chlorides in salt water (be it from the sea, or de-icing salts) will slowly penetrate the concrete cover and lower the pH of concrete. This means that steel looses the alkaline protection provided by the concrete and rusts.
There are two main ways to prevent corrosion from developing. The first one consist in chiseling away the concrete cover, leaving the steel exposed and shotcreteing a new cover. It is possible to estimate the penetration rate of chlorides and thus specify a thickness of the cover that will last for a given number of years. 50 years, for example. An alternative solution is to use a cathodic protection system. This means applying a current to reinforcement steel such that even if it looses the alkaline protection by the surrounding concrete, it does not give away ions, so it does not corrode. This system has an unlimited lifespan and is cheaper, but requires monitoring to ensure that it works properly.
If you think that the organization responsible for bridge maintenance will do a good job operating and maintaining the cathodic protection system for the next 50 years, then you should choose it. This means that three or four generations of engineers have to get familiar with the system. There must be a way to preserve and transfer knowledge, but not only that, maintenance of the system must be properly funded by the bridge owner year after year.
Back in 2016 the Norwegian Public Roads Administration started a program to repair and retrofit with cathodic protection systems a number of bridges in Northern Norway. I think it was more than a technical decision. It showed confidence in the continuity and presence of an administration that will take care and maintain these systems. Only time will tell if it they were right.
I often think about the decision of Germany to close their nuclear plants after the Fukushima accident. It is puzzling to me why people in Germany would want to shut down relatively modern plants with a good safety record considering that Germany is surrounded by other countries that also have nuclear plants, many of them much older and in worse condition. The German decision gave more incentives to keep other plants in operation, thus exposing the population to higher risk of a nuclear accident.
Now I think that another way to interpret this decision is that people in Germany do not trust their institutions in supervising, monitoring and emergence planing for nuclear accidents.
Last updated: 2022-03-06