In a book i've read the hero was saying that if you believe the end of the world is imminent, and you are contemplating suicide, then most likely you are in a cult.
Unfortunately modern environmentalism is a cult with its own armageddon. And WWF actively displacing native hunter gatherer people to "save the wildlife". What is the point of preserving environment if there are no people in it?
In fact shrinking population is the worst thing for the environment that can happen now, because at this point we have already activated the natural process of arctic melting and releasing CO2, and even if half of people were magically removed there wouldn't be a huge difference.
On the other hand the new science and technology depend on large number of people ready to pay for them. Things like starlink, new CPUs, would be impossible with smaller population. But if the population was larger, we would already have floating cities increasing carbon capture in sea, desalination plants irrigating large parts of sahara, system of balloons, solar updraft towers and satellites controlling the local climate.
If you are from a rich country, not having children is doubly bad, because you have all the resources to give these kids better education. The world would have been a much better place if people from western countries were immigrating to the rest of the world bringing their money and their knowledge of how to build a better society, but instead of that the rich countries are making easy for smart and entrepreneurial people to immigrate there leaving us perpetually underdeveloped. (When most of the people who were exposed to western values, and had good education immigrate, there is not enough power remaining to fight with those who want to build medieval dictatorship).
