[lopmotr]

How can you destroy water? It literally falls out of the sky. Israel makes drinking water from sea water. How can you destroy all food? There's no way we can wipe out all plants and animals, and we can eat lots of them, even if they're not our favorite food today. You can even eat cockroaches.

You're confusing actually destroying the things we depend on with carelessly using them and not trying to make sure they survive. An obvious counterexample - we do our best to eat as many cows as we can, yet the species is thriving! Maybe fish farms will do that to desirable fish species too. We didn't even wipe out sperm whales despite whalers doing their best to find all they could and having no concern for conservation.

I agree there's a _risk_ of that happening though. We just don't know for sure. My concern is with people who claim to know for sure when actually they're taking a dishonest extreme position to make their political point stronger. Of course we should be careful not to destroy the environment because if we don't, the downside to being wrong is terrible. Somehow most of the people arguing about this seem to be victims of their own extremism and unable to distinguish risk from certainty.

[mikeash]

Water is doable as long as you have enough energy to decontaminate it, which is not really a given. Food, I'm not nearly so confident as you. Cows thrive partly because of what we do with them and partly because of all the natural stuff we can use to do so. Sperm whales weren't wiped out because that particular act of environmental destruction was checked before the species disappeared. You can find plenty of examples of species that were hunted to extinction, that just happens to not be one of them.

To say that unchecked destruction of the environment won't necessarily destroy us is the same as saying that we'll be able to create closed-loop life support systems that can operate indefinitely without any outside organic input, and that we'll be able to do it fast enough to save ourselves. I'm highly dubious of that.

[lopmotr]

You're assuming that 'unchecked destruction of the environment" means all important species will be made extinct. That's not true. We do our best to destroy various pests but they keep surviving. Many species have been wiped out and everything's still going fine. How much damage do we have to do to cause important ecosystems to collapse? I'll bet nobody knows because it's too complicated. Again, it might happen but nobody's certain so it's a lie to say that it's certain.

Something I'm pretty sure of though is that we can never destroy all food-producing life on earth by just eating everything till it's gone. Whatever's left will thrive and can be used to make food. Maybe not as tasty or as cheap, but we won't need a fully artificial life support system. Even in an extreme case of desertification, we can still grow plants indoors, and rain will still fall on our "deserts". And that's the very extreme! In reality, maybe the price of beef will go up a little as farmers have to spend more on feeding them.