What do you think a sustainable way of life looks like? In terms of both global population size and typical life experiences.
That's why I expect we're headed for tragedy- we can't and won't collapse everyone's consumption to that level. The people who consume the least will be the most hurt by the ecological consequences of what we in the high-consumption regions of the world do.
Bad news, I’m afraid: If you keep the population and technology constant, the maximum sustainable consumption per person is lower than basic metabolic needs. Either the tech or the headcount needs to change, and nobody is going to let it be their head that gets dis-counted.
The main reason for this isn’t energy (current tech includes really cheap PV we just have not yet gotten around to building but could and likely will), it’s phosphorus. Phosphorus is mined for use in fertilisers, it isn’t renewed, the run-off flows into oceans.
Only thing we know of that might help is more tech, and the tech seems like it needs high-consumption societies to get proper funding.
Naturally, if you can get good research going without that, that’s a massive win for everyone, not just in this aspect.
I'm not saying that this applies to your arguments, but what I notice among many people and groups claiming to be concerned with our impact on the environment is more of a fetishism towards doom and pushing forward a notion of personal sacrifice for billions of people, while actively making any excuse for decrying numerous suggestions for technologies and social advancements that could possibly let us make the world cleaner while also being able to live better on a much broader scale.
That kind of thinking teeters on the verge of pseudo-religious, ideological instead of being something reasoned and practical.