Evidence increasingly appears to show that an extensive pre-colonial iron industry may have overtaxed the environment, leading to deforestation and eventual social collapse in parts of Africa. Modern Africanists often lament the loss of the famed indigenous African iron industry.
Just about every agriculturalist African culture had impressive ironworking industries. Evidence of this industry exists in the form of massive iron slag heaps, such as those that can be found in archaeological sites such as Northern Sudan and the Niger and Senegal river valleys. However, is it something to really mourn? Considering the environmental toll that such an iron industry had, we probably shouldn’t.
In this article, we investigate the nature of the iron industry throughout pre-colonial Africa and how that could have contributed to environmental and social collapse. In particular, we will look at the examples of the Western Sudan, the portion of West Africa that encompasses the Southern Sahara and the Sahel, as well as Ancient Nubia, a Nile Valley civilizaton located to the south of Egypt.
How did an ancient iron industry In Africa hurt the environment?
Because it requires huge amounts of biofuel (or firewood) to operate, Iron smelting would have increased the risk of environmental catastrophe from deforestation. Iron smelting has long been considered a highly sophisticated pryrotechnology.
This is because exceedingly high temperatures are required to retrieve iron from its ore. Some experts believe that long experience (and by long, we mean 100s of years) with other “inferior” or “easier-to-operate” metals such as zinc and bronze, which are easier to work with because of the much lower melting points, is required as a kind of apprenticeship to prepare a culture for proficiency in iron smelting.
African archaeology defies all such expectations. There are only a few examples of these precursor metallurgy industries, such as zinc working. However, there are numerous examples of fully-fledged and sophisticated assemblages of ironworking sites throughout Sub-Saharan Africa, with many of them being quite old.
The oldest and most controversial in the central African site of Obouie, which has been dated as far back as 2000 BC, making it essentially the oldest iron working site in the world. Table 1 provides some notable examples of famous ironworking sites and their ages located throughout Africa. For a more comprehensive example, you can check out this useful article by Stanley P Alpern and this alternative view by Augustin C. Holl.
Table 1. List of a few early iron sites in Africa
Country | Site | Date |
Niger | Termit Masif | 1302–986 BC |
Nigeria | Lejja | 2571–2491 BC |
Cameroon | Olinga | 1096–910 BC |
Gabon | Otoumbi II | 883–691 BC |
NOTE. This is from A.C. Holl: Early West African Metallurgies: New Data and Old Orthodoxy.
Understanding the techniques for iron smelting in the African past requires some knowledge of the general or universal principles of iron smelting. Iron can only be smelted at a temperature of 1250°C (2282°F or 1523.15K). As can be assumed, this would require an immense amount of energy. While we rely today on fossil fuels for an energy source, in the past, wood would have been the typcial source of fuel that was used for iron smelting.
The high smelting point of iron would mean that plenty of firewood would be required. In particular, hardwood trees like acacia would be preferred. Therefore, the more intensive the iron working and smelting, the more firewood would be needed and the more trees would be cut down, leading to deforestation.
How did ancient iron-smelting furnaces work?
African iron smelting technology primarily relied on the bloomery process. This involved a chimney or pit, inside of which the iron ore and charcoal would be loaded to burn. In addition, a tuyere or an opening on the outside side and bottom of the pit wall, to allow air to be blown in either through natural drafts or via hand-operated bellows was used to induce temperatures high enough to allow the iron to smelt. Below is a pic of what a traditional bloomery furnace would look like.
This is a diagram of the bloomery furnace used by the Haya people of Ethiopia.
The resulting by-product of this process would have been slag, that is the unwanted impurities of the iron, and the bloom, which would be the purified or semi-purified iron.
The Ecological Settings of Iron Smelting In Africa
Iron smelting was prevalent throughout Africa; however, its debilitating environmental effects in the form of deforestation would have been in the semi-dry or semi-arid regions of the Southern Sahara and the Sahel. The Southern Sahara and the Sahel is a region that stretches from the West Atlantic seaboard to the Egyptian and Nubian deserts on either side of the Nile Valley.
The ecology of the Sahel is defined by grasslands. These are areas that include mostly grasses and widely spread woodlands. These types of environments are ideal for grazing by wild animals that depend on grasses, such as wild deer, wild buffalo, and of course the predators that rely on them. In addition, they are also suitable for animal herding (e.g., goat, sheep, and cattle) and rain-fed agriculture.
Photo by Magda Ehlers on Pexels.com
The civilizations or cultures that appeared to have been negatively affected by iron smelting would be Ancient Kush, located to the south of Ancient Egypt, and which was once dubbed as the Birmingham of Africa on account of the obvious evidence of massive iron slag heaps found at Nubian sites. The second was the empires of Medieval Western Sudan, the medieval kingdoms associated with the Niger and Senegal River valleys.
Several complicated interlinked factors probably explain the collapse of these societies. However, researchers have cited the overtaxing of the environment as one of the factors behind their collapse. But here, we will take a brief look at each of these examples in turn.
The Medieval Western Sudan
The Southern Sahara and the Sahel, especially its western sector, was the home of a number of famous civilizations, namely Medieval Ghana, Mali, Songhai, and Kaw-Kaw Empires. These were mostly successive empires, that relied on the trading and agricultural complex that arose from the Senegal and Niger River valleys and the trade of gold from Africa and prestige goods from the Islamic world. Their trading networks were far-ranging and widespread and stretched from West African rainforests to cities in Andalusia Spain and throughout the Islamic Medieval world.
The Medieval Ghana Empire
For our purposes, we will look at the Ghana Empire that was located mostly in what is known now as Mali and partly in what is now known as Mauretania. It should also be noted that it was located between the Senegal and Niger River valleys. The Medieval Ghana empire lasted from Date to Date. It is most famous for providing gold to the Islamic world, which was used to mint dinars or coins in the Islamic states. The Ghana empire sourced its gold from the southern regions of W. Africa, and the king appeared to have a monopoly on this production. Islamic travelers and scholars described Ghana as an exceedingly gold-rich empire.
But gold was not all that the Ghana empire had to trade. Archaeology has revealed just how complicated the Ghana empire was and the structure of its towns and settlements. Arab travelers and accounts describe how the Ghana empire was dependent on a dual-city system, a royal town with the palatial residence of the king and his ministers and other government officials, and a commercial town, which included Islamic merchants, who were most likely Wangara, Soninke merchants who had adopted Islam or Islamic culture for the sake of trade, and the foreign commercial agents from North Africa and the wider Islamic world. Ordinary citizen settlements were scattered in between these two towns.
In addition to these historical accounts, modern archaeology has also shown that these towns had a number of satellite towns. These satellite towns were organized according to the category of craftsmen who occupied them. For example, in the Mema District of Medieval Ghana, there were towns dedicated to the construction of pottery or iron smelting. Pottery just like iron smelting would have been a biofuel-intensive industry, requiring large amounts of firewood.
The empire of Ghana lasted from the 7th–13th century. However, it was slowly eclipsed by the rise of the Mali Empire. Historians claim that evidence suggests that a successful military challenge by the Mali Empire, a kingdom predominated by the Mandinka people, explains the ultimate collapse of Medieval Ghana. However, archaeological evidence suggests pressure on the environment, which was being overtaxed to support the economic activity in the region may have played a major role.
How Would Iron Smelting Lead to Collapse in Medieval Ghana?
As mentioned earlier, the trade networks of Medieval Ghana would have been wide-ranging. A massive demand for the goods produced within this state would have created a vicious cycle. Towns would need to expand to meet demand. And these towns would have their own energy demans that would have to be sourced from firewood. Although wood is a renewable, the rate at which it would have been extracted would be too intensive to allow for it to replenished fast enough to make it sustainable.
In particular, two medieval industries would have been largely responsible for overtaxing the local environment: namely, the cermaic industry and teh iron industry. Ceramics have been described as the “plastic of the ancient world.” It would have been ubiquitous and used just like plastics for a wide range of purposes, including storing water and food and carrying goods over long distances. Also, just like iron smelting, it was an industry that relied heavily on energy. Ceramics are made from clay, which would need to be heated to give it temper, that is, the ability to not crumble or break as one would expect of soft clay.
But by far, iron smelting would have been the main culprit in the environmental stress that would lead to savanna woodland being converted into desert. The exceedingly high temperatures required to smelt iron would mean huge amounts of firewood from species of hardwood trees would be necessary. These trees play a crucial role in preserving soil and retaining moisture through their root systems. If they were cut down more quickly than they could grow back, this could spell environmental disaster. In their absence, the soil would detoriate rapidly, and previously fertile soil that could have supported farming and livestock ranging would turn into barren desert.
The factors behind the decline of the Ghana Empire are complex. Historians point to the rise of their rival–the Mali Empire–in the fourteenth century as the primary reason. However, this type of environmental stress and degradation undoubtedly played a role in weakening its economy.
Medieval Ghana is not the first empire to fall victim to environmental degradation.
Other famous examples include Angkor Watt in Cambodia, The Easter Islands, and the Ancient Maya. Today, the rapid and intensive industrialization that defines our modern and globalized economy and the phenomena of global warming and climate change also may pose a similar threat to our modern civilization.
Cite this EminentEdit article |
Antoine, M. (2024, September 17). Did a Precolonial African Iron Industry Expand the Sahara? https://www.eminentediting.com/post/did-a-precolonial-african-iron-industry-expand-the-sahara |
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