Yes, there is a limit to how many humans can probably sustainably occupy the planet, however I don't think we're near that if we actually tackle the problem of how to live in a sustainable way with nature.
It's not a black and white issue between government, big companies or the individual, it's actually all of those. Consumers can shape demand, but governments must help incentivise change, and big companies must invest wisely and potentially even re-invent themselves. If we can do all those, we have a chance to avoid some of the worst impacts. We're already too far gone to prevent any impact, some bad **** is going to happen this century whatever we do.
I think that when I'm now making decisions about what to buy, how to live etc. I'm thinking more and more about the environmental impact of what I do. I encourage you to as well. I have children and I would love to leave them in a world that was better than the one I arrived into and previous generations have given us. That's motivation enough. Can I afford solar panels, a new electric car, a heat pump system etc. - No, I can't. So this is where government needs to step up and companies need to make wise decisions as well. Then we have to make good personal choices. If a sustainable option was a comparable price, or even a bit more, maybe with some inconvenience, I would still jump on as I know it's the right thing to do, which could help accelerate change. I could probably do more, but I find myself making little changes all the time that hopefully will add up.
To those who think this is some left-wing propaganda or political issue, overall it really isn't. I would think the vast majority should now accept this as an anthropogenic issue and if you can't, probably best to step aside for a bit. This is a matter of survival for our (and many other) species. Sure, let's debate about how best to solve the problems, but obstructing constructive dialogue is like letting the clock run out when you're losing instead of trying to win the game.