Another point on this topic is that I think Carl Sagan had good advice when he said "Extraordinary claims require extraordinarily good evidence.". From that perspective, I've frequently found that the poster who asks for citations is actually the one making an extraordinary claim (either implicitly or explicitly). So in this case, since I've been concerned about the environment for 40 years now, I find your (implicit?), claim that we have nothing to worry about when it comes to the environment is actually the extraordinary claim, and that my claims are the common knowledge, ordinary claims.
Next, there is a way in which demanding citations is quite arrogant. It implies that the demander is somehow the arbiter of what's common knowledge and what isn't. My personal approach is to rarely ask for citations. If I'm ignorant on a topic, I usually spend a few minutes with my favorite search engine. Typically, I ask for citations only when I feel pretty well grounded in a topic and I hear something that doesn't agree with what I think I know.
IMO, most people haven't thought much about "topsoil depletion" or "aquifer depletion". That doesn't matter, I think any honest person would admit that they are ignorant on most of the world's topics, and who cares.
But in this case, you decided to wander into this thread, no one pulled you here. So I'd say, if you're ignorant about topsoil depletion,