Say, how'd you attempt to tackle the belief that us over fishing, over hunting is just the natural order of things? Humans in order to survive have stocked up on surpluses of food and other necessities. Some argue that it's very difficult to distinguish between over-consumption and necessary intake.
Environmental issues are a lot more serious than most people seem willing to acknowledge, and I think talking about food supplies is probably the best way to get them to change their minds. Hardly anybody cares about global warming or the extinction of various animal species, but if you tell them about how it affects their food *right now* then they might sit up and listen. Long-term thinking and planning for the unexpected are both areas humans (as a group, not as individuals) are not great at, sadly. Show people how a problem affects them right now and then they start to care. Then you have the door open to talk about further sustainability-related issues.
Personally I do find this statement may hold some truth theoretically speaking, but given most cases, in today's world it holds little value: for example, factories manufacture huge volumes of livestock such as chicken or cows being reared for meat and such a method is apparently a prime example of overproduction. One does not need much further study to deduce that its an evident form of over-kill so to speak. But besides in such cases like the above do you guys have any other reasoning for why it is not natural for us to over-consume or at least, over-produce food products for ourselves?
It seems like manufacturing, doesn't it? But in fact, livestock shouldn't be "manufactured." It's supposed to have been
raised. It was very well put in a podcast I was listening to earlier today (paraphrase): the misery the animals go through in factory farms becomes misery for us down the road. Just because we don't see, hear, smell, feel the torturous life they're put through, doesn't mean we don't suffer from it ourselves in the form of inferior and only weakly nutritive meat, eggs, and dairy. Even if you don't want to take "you are what you eat" that far, it's sad that what
should be the most nutrient-rich foods filled with pre-formed vitamins, organic minerals, etc., are so poorly taken care of (tiny, filthy factory pens), at best they end up becoming the equivalent of a watered-down bar drink and at worst they can be outright dangerous.
My point is more along the lines of the current world production of food being enough for everyone. The issue in africa is a tad more complicated though. As far as I know, however limited, they have the issue that they can't grow much food and they cannot buy it because they are pretty poor. If they could buy food probably someone would sell it to them after all.
Africa has plenty of food, contrary to the tired old narratives of Western media. It's a diverse continent incredibly rich in natural resources, with accordingly diverse and significant (and growing) global exports. I hate to generalize, but food distribution problems there usually have little to do with supply. They're largely
logistical, and/or due to lack of
infrastructure. Often the same nation that has a famine in one isolated rural region can have a food surplus in another because fresh foods from the latter location will spoil before they can be transported to the former. It
is a problem though, when outside nations will pay a significant amount more for a food export than people can to buy it locally. Then there's commodity price speculation on food by investment bankers, driving up prices.
I think the biggest threat to food supplies globally is unethical business practices, honestly.
Interesting point about the phytoplankton! I already preferred the idea of building upward like you said rather than building on the ocean after seeing a documentary on it a while ago, but even just somewhat limiting our oxygen supply is a scary thought.
A good question would be, WHY SHOULDN'T WE? Nature has provided us with everything we need. Air to breathe, water to drink, food to eat. Why shouldn't we give back and preserve the nature / environment? Isn't that beneficial to us too? Also, it is not so hard, is it? Just make sure you turn your tap completely, so there will be no leaks and to segregate our trash correctly. No sweat!
I entered this phrase in google and came up with pretty good site discussions : why should we preserve our environment
Aren't you concerned about coal emissions or oil spills that pollute the land, water, air, and our food, and lay the costs of all this damage on the public? How do you convince people not to drive cars when so many people look down on public transit, OR convince car companies to make electric cars while also convincing governments to invest in interconnected, intentionally-redundant nationwide electric grids to fuel those cars? Will oil companies stand for that? What about commercial aircraft and (especially) private jets? Can we convince rich people to go book a first class car in a bullet train instead of just hopping into their own planes? Will people happily give up the ability to buy the most common fruits at any time of year and go back to seasonal buying to reduce emissions?
Anyway, I don't think the public is as much to blame for most of this stuff as government/business failure to act. Governments
should be working to find the most beneficial long-term solutions for everybody, but instead they're all corrupt and bought out by those who want to make a quick buck.
). 
I really do appreciate it.
