Really? Is this a genuine comment? That a medieval world population of (optimistically) 500 million would produce more hazardous materials and waste than an industrialised world population of 6 billion?
You can't possibly think that your environment is worse than the common environment of a medieval european. You have a house insulated from the elements, a wide variety of food sources which you can't imagine ever running out, you've never gotten a disease from drinking the water available to you... and on and on.
The worst you have to worry about is accumulation of toxins that may take decades to manifest into disease, and maybe if you live near a coast, you might have to move inland a mile in 40 years.
Modern technology and productivity have almost entirely insulated us from environmental problems. Ask yourself if you or anyone you've known has personally experienced an environmental problem that was anything more than a mild inconvenience or irritation ... or not entirely based on fear for the future.
Likely in reference to their inability to deal with the conditions they faced, either created directly or indirectly by themselves to say nothing of what nature could do.
I am quite sure we all acknowledge modern man is very capable of wrecking the environment, we are however able to prevent much of it and even correct it. It never ceases to amaze me the amount of dangerous materials we work with everyday that never impact the environment
