I suppose it depends upon what you mean by sustain life. If somebody is hooked up to life support in a hospital for the rest of their life, does that mean their body is able to sustain life or does it mean the hospital is able to sustain life? That is somewhat similar to what we are talking about. All of this technology is wonderful to introduce stability, to get us through the rough patches, but a permanent dependence upon it is questionable.
As for that native gentleman, I'm not sure what the situation is down south, but the prairies of Canada and the Northern US have been known to have dry spells. The 1930's were particularly bad, but apparently early explorers returned conflicting reports about the habitability of the prairies simply because of the variability in precipitation across the years. Of course, aboriginals would have knowledge of that since they inhabited those lands for time immemorial. I have even seen suggestions that those who lived in the regions were nomadic since they had to follow the food (which, of course, had to follow its own food). This is in sharp contrast to those who inhabited other parts of the Americas, who were settled.
It can't sustain 40 million people who all want a pool, a grass lawn, freshly-grown fruits/nuts/vegetables, air conditioning, large-scale manufacturing, golf courses, etc.
Like I said, it is literally sustaining this as I type this comment. You just don't like the consequences (the Colorado river isn't making it to the ocean).
Perhaps it is, but that's not sustainable. Every ecosystem has a carrying capacity. We're coming closer and closer to that for the Southwestern US. It won't be pretty when we reach it.
I actually couldn't care less whether the Colorado makes it to the ocean. I have two major rivers in my city. There's plenty of water without having to fine people for using water on the opposite of their odd-even day. The heat during the summer is uncomfortable but it's usually not an imminent threat to human life after an hour of unhydrated exertion.
> Every ecosystem has a carrying capacity. We're coming closer and closer to that for the Southwestern US.
The limit of carrying capacity is the limit of sustainability. If the system is coming closer to the carrying capacity, the current state, having 40 million people with lawns, is sustainable!
If your argument is that having 200 million people with lawns is unsustainable, say that! But that's not what you said.
It's not just lawns; you're being purposefully obtuse.
There are already towns in California experiencing spells of not having any potable water [0]. We've pumped so much water out of parts of California that some land has dropped almost 30 feet [1]. Wildfire season in the southwest, including California, is now longer and more severe than it once was [2]. Arizona has passed resolutions imploring Congress to investigate diverting water from the Mississippi River out west [3] which is almost guaranteed to cause serious political confrontations.
So, no, the current state of things and the projected growth isn't sustainable. When you're honestly considering the idea of building a continent-wide aqueduct system to keep golf courses in Phoenix playable, you're better off packing up and heading back to the Midwest and Northeast to repopulate towns that have infrastructure we already bought and paid for decades ago.
I mean they were wrong, it obviously does sustain life. You're just grumpy about what it looks like.