"I’m talking about more than doing ten things a day to reduce global warming."

First things first. Prove "global warming" is not a naturally occuring cycle in the Earths life cycle?

E=mc2

Energy is never lost, we dont "deplete resources", we can only change the nature of the resource. What might be considered 'waste' today maybe the energy source of the future.

Good to be back on topic

<i>it’s actually really hard to picture and live a life that does “more good” for the planet rather than “less bad”</i>

That's the typical complete nonsense answer you get when you haven't sorted out the question properly.

The planet will live and die according to its natural cosmic cycles and forces no matter what any of us do. Short of saving it from a direct hit by a comet or large asteroid there is nothing the human species can do for it.

Likewise the biosphere will survive and evolve with or without us. We might be able to make some little tweaks here and there for a short time to influence the population distributions of some not very important species but that's about it.

The only meaningful interpretation of sustainability is as sustainability of human life. If your desire to "help the planet" really just equates to aiding the sustainability of human life then of course we get completely different answers to the question.

All kinds of efforts, work and innovations contribute and very many people are involved. IMO this is a far more realistic way to view the world than the blinkered religious purity of environmental activism.

I'm at a loss to understand how anyone with this sort of thinking can actually justify having children, as surely these will cause a massive debit of the so-called "bad" environmental effects. How is that ever going to be negated?

The only human lifestyle that has not caused mass extinction and environmental degradation is that which pre-dates fire and hunting. Indigenous peoples (eg aborigines and North American first nations) are often cited as living in harmony with their natural environment. Harmony? There is no such thing in nature. Fossil records show extinction of large herbivorous mammals coinciding with the arrival of human hunters on both the Australian and American continents, closely followed by the extinction of large carnivorous mammals.

Civilisation as we know it is fundamentally unsustainable.

What true 'sustainability' really requires is a true return to nature, predators and uncontrolled diseases and parasites. In those circumstances nature would make pretty short work of most of us, which is how ecosystems work. Most people won't take that deal.

If civilisation is to persist at all, we are stuck with some major changes to this planet, and those changes will probably thin out our population as well. The planet has a way of correcting course.

Species will comes and go, adapt and fail, including humans eventually. However the planet will endure and life will generally flourish in some assemblage. It has been that way for a billion years, and will continue for a few billion more, at least until the next scheduled supernova.