The biggest hope at this point honestly is that fewer people are having kids and we're on track to halve the world population in another couple generations. Greenhouse emissions cut by half.
Halving the population in 50 years is not a realistic plan.
Here are some projections to support that statement. Supposedly 2084 is peak population.
https://population.gov.au/sites/population.gov.au/files/2025...
I haven't read up on all the assumptions made for those projections. If something unassumed pops up that makes things substantially worse then the population peak would come earlier I guess. But that's a gamble.