[lopmotr]

Since you can't see the fault in your analogy, I'll tell you. People have already tried that and we have biology that tells us what would happen without those things. So we know the answer without having to test it again. It's not comparable to continuing to change the environment the way we are, which is something we don't know the effects of.

[rosser]

Ecosystems are massively interdependent. There is necessarily an inflection point where an ecosystem is so depleted that it can't carry itself any more, let alone us. That's called "collapse" and it tends to be permanent.

Species are currently going extinct at a rate we've previously only seen in the fossil record — from which we've estimated that the current rate of species extinction to be on the order of 10-100 times that of any previous extinction event.

Then, consider that there are key roles in an ecosystem, without which its collapse is more or less a certainty. One of those roles is pollinating.

The collapse of bee and butterfly populations, and our having to resort to commercial pollination (because something on the order of 3/4 of the world's food plants require pollinators, and many of the essential nutrients — things the body can't synthesize itself, and must obtain through diet — come from plants which critically depend on pollinators, while wild bee populations have fallen to alarming levels) is a dangerous leading indicator.

We're well on the path towards a collapse. If we don't avert it, things will not go well for us. When the things we eat all die, they aren't there for us to eat any more. When that happens, we die.

How is this not flashing neon obvious?

[lopmotr]

Life on Earth has never been wiped out, no matter how bad it got. And we're not even talking about glaciers over every continent bad (humans survived that), just less fish and some other things. Not even always making them extinct, just less of each species. You're assuming that if we carry on without worrying about it, we will make important species extinct. That's only an assumption and not obvious.

[mikeash]

We need the environment to provide air, water, and food, so if you keep destroying it then eventually this will go from analogy to direct consequence.

[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.