There’s a sustainability theme on Scientific Gems this month, and I thought I’d take a look at sustainability in the Middle Ages. The Middle Ages get a lot of unjustified bad press (people did not think the world was flat, for example).
It is more accurate to describe the Middle Ages as a search for sustainability. The rise of Christianity meant the phasing out, and eventual elimination, of slavery in Europe. That meant a need to replace the use of slaves as an energy source. The Middle Ages therefore saw a steady increase in the use of water power, tidal power, and wind power.
Another transformation was needed in agriculture. The collapse of the Western Roman Empire and the Arab invasion of Egypt meant that the rich Egyptian grainfields could no longer feed Europe. European agricultural productivity therefore had to be increased to feed the population, while being sustainable on a time scale of centuries. The mouldboard plough was an important piece of technology here.
Another key development was the introduction of three-way crop rotation. A field produced grain for a year, and was used as pasture the next, thus fertilising the soil with manure. The third year, the field produced legumes, which added nitrogen to the soil, and the cycle repeated again with grain. Three-way crop rotation was both more productive and more sustainable than the older two-way system. There’s a lesson to be learned here, I think.