Why not 25 million or 1 billion? 1 billion seems pretty sustainable to me. I don't know of any ethical way to produce that kind of decline in a human lifetime.
The world will look very different in a few decades. Nigeria will probably surpass the population of the USA. Europe will lose 30 million or so people; that I would suppose would be largely replaced by immigrants from Africa. The majority of future population growth happens in Africa over the next 40 years. The UN predicts about a 25% chance that world population will stabilize by 2100 (at around 10 billion). With some saying we're already over world carrying capacity, this is very worrisome. Probably the number one thing the average person can do to fight climate change is not have kids of their own and adopt.
The world will look very different in a few decades. Nigeria will probably surpass the population of the USA. Europe will lose 30 million or so people; that I would suppose would be largely replaced by immigrants from Africa. The majority of future population growth happens in Africa over the next 40 years. The UN predicts about a 25% chance that world population will stabilize by 2100 (at around 10 billion). With some saying we're already over world carrying capacity, this is very worrisome. Probably the number one thing the average person can do to fight climate change is not have kids of their own and adopt.
I'm not anti-Christian. I'm anti-stupid.