Environmental Impact of Trade: Agriculture, Disease, and Population Shifts

Hi and welcome back to Heimler’s History. In the last video we talked about the cultural consequences of the connectivity provided to cultures through trade.

This video is going to explore the environmental consequences of connectivity. And if that sounds boring, don’t worry, by the end we’ll have talked about bananas and worldwide death.

Let’s get to it. We need to talk about two major categories of things that spread through networks of exchange: agriculture and disease.

So let’s start with agriculture. As merchants travelled from place to place they introduced crops into lands which had never seen them before and that had big consequences.

One of the most significant of these crops is one I’ve mentioned several times in other videos, namely, champa rice. It was introduced to China by merchants who travelled from the Champa Kingdom in Vietnam.

This strain of rice was drought resistant and could be harvested several times a year. This, of course, led to massive population growth in China, but the environmental impact of champa rice was significant too.

The introduction of this crop led to the transformation of the land, namely, terrace farming. This was a method of farming that made previously unfarmable land farmable by cutting steps into hillsides so that you could plant rice.

And again, the more food that was introduced into China the more the population grew. Another significant crop introduced by merchants was bananas. This time it was Indonesian merchants bringing this foreign crop into subSaharan Africa.

And this was huge because when the Bantu-speaking natives of Africa learned to plant this crop it changed the course of their entire lives. Their main food staple was yams, and that means they lived in the places they could

grow yams. But with the introduction of the banana, they could move to regions where yams couldn’t grow, and spoiler alert: they did.

So because this Indonesian fruit was introduced into Africa, whole populations migrated. And this same kind of thing happened elsewhere too and in general when new crops were introduced, population increased.

But when population increases, that puts more pressure on the land, and as you can imagine, consequences will follow. For example, overgrazing in Great Zimbabwe led to such severe environmental degradation

that the whole city was abandoned in the late 1400s. In Europe the land was changed through deforestation which eventually led to a profound erosion of the soil.

Combine that with the Little Ice Age that began in the 1300s, and you’ve got a severely contracted agricultural production. Okay, those were some of the environmental effects of trade with regards to agriculture,

let’s look now at the spread of disease. Lots of diseases spread through merchants arriving on new shores, but surely the most significant of them was the Black Death or the bubonic plague.

Now we understand today how this disease was spread: namely through fleas. So fleas would bite a carrier infected with bubonic bacteria. Then the bacteria multiplies in the flea’s guts and eventually there would be so much

bacteria that it clogged the fly’s guts. So then they would bite a human and regurgitate the bacteria into the bite. And to me that’s just insulting because not only are you getting the Black Death in

your blood stream which will kill you in a couple days, but you’re also getting honked on by a flea. Now thanks to our friends the Mongols and their unrelenting lust for more land, as they

pushed further and further into new territories, they unknowingly brought these fleas with them. But the Mongols can’t bear ALL the weight of responsibility here, the spread of this

disease also came along trade routes, especially ships that provided homes to infected rats. But not only that, as merchants travelled over land they stopped to rest in what were called caravanserai.

These were little places that dotted the length of the Silk Roads where merchants could rest and sleep. However, they did so in close proximity to animals and animals have fleas.

So all that to say, the Black Death was a major consequence of connectivity during this period. And when it showed up in a town, the consequences were devastating.

Probably the most famous account of the effects of the Black Death come to us from a European by the named of Giovani Boccaccio in his book called The Decameron. Here’s a little taste:

"The symptoms were not the same as in the East, where a gush of blood from the nose was the plain sign of inevitable death; but it began both in men and women with certain swellings in the groin or under the armpit.

They grew to the size of a small apple or an egg, more or less, and were vulgarly called tumours. In a short space of time these tumours spread from the two parts named all over the body.

Soon after this the symptoms changed and black or purple spots appeared on the arms or thighs or any other part of the body, sometimes a few large ones, sometimes many little ones. These spots were a certain sign of death, just as the original tumour had been and still

remained. And maybe Boccaccio’s best summary of the effects of the disease is this: The victims ate lunch with their friends and dinner with their ancestors.

Yeesh. Anyway, this dreadful disease found its way into many societies of Afro-Eurasia, primarily by means of trade.

And after all was said and done, it killed huge numbers of people. In fact, in Europe most estimates are somewhere in the neighborhood of half of the population. Now as you can imagine, this situation had significant consequences.

Maybe one of the biggest was economic. The Black Death changed the relationship between workers and lords in Europe, for example, because now that half the population was wiped out, workers were all of the sudden pretty

scarce. And with this higher demand for labor, power for negotiation of wages shifted squarely into the hands of the surviving workers.

Okay, that’s what you need to know about the Environmental impact of trade. If you’re in AP World history this year, then subscribe to this channel and I’ll help you get an A in your class and a 5 on your exam.

If you like hearing about fleas honking death on human beings, then hit the like button and let me know. Heimler out.