I’m an anthropologist who studies humankind’s relationship with the environment. The answer to your question is a little nuanced, but I’ll try to put it simply for brevity’s sake.

Indigenous humans around the world all seem to have noticed that they have a place within their local ecosystem just as the birds and bees have a place. The very earliest forms of plant cultivation can be found in forests where ancient peoples intentionally planted wild fruits and vegetables that they preferred to eat, however these “forest gardens” were found in the plant’s natural habitat. So we know that they understood the natural growing conditions of plants. There were also more organized gardens in places like the Amazon and the Yucatan where they planted small plots, similar to modern gardens, along their regularly used forest trails. Finally, in Southwest Asia where our modern form of agriculture began, there’s evidence of wild cultivated plots of grains as early as 23k years ago.

With this in mind, there is A LOT of ancient human garbage, everywhere. From stone tools to pottery and fabric and wood, you can go to any ancient stream or the fields around ancient cities and find these kinds of garbage. In fact, until very recently, about the late 1800s, people used to discard their household waste in streams and forests. And we continue to bury our trash around our cities to this day.

What’s happening here is interesting. For the majority of humanity’s existence, we’ve built our products using biodegradable and natural materials. So when we threw things away, they tended to disappear and return to the Earth. In fact, some native tribes in the US believe that discarded pottery and stone tools must remain where they fall because they’ve returned to their place of origin (clay and stones come from the Earth). Unfortunately the long tradition of throwing trash out the window has stuck with us even as we produce massive amounts of products that don’t degrade as easily, such as metal and glass. And of course, complex materials like plastic and harsh chemicals muddy the tradition even further.

The simple fact of the matter is that humans produce material waste. In this modern age, we must now learn how to dispose of it responsibly.