I guess we all agree that continuing as is is clearly unsustainable. The one and only alternative to full human extinction is radically scaling down humanity, primarily quantitatively. We would still need some amount of people, ideally geographically distributed to stay resilient against god knows what else will come in the future.

I am not well versed at all in the multiple disciplines one needs to talk about this in technical detail, but I guess 500.000 people per habitable continent should be enough?

I do realize this is impossible to enforce top down or get the people to do bottom up. As the evolutionary greedy animals we are, we will continue to procreate.

After all this rambling my short, personal answer: The only possible thing is becomming true eco terrorists and genociding 99% of the world population somehow. Boom. 99% of the ecological/climate foot print humanity has evaporated!

To the appalled reader: I‘d prefer reasonable counter arguments over downvotes and flags...