Highly religious people like Mormons and Amish have 3 kids on average, same for highly religious societies in Africa and Asia. Fun times ahead. Ironically from a darwinian point of view religion is a great adaptation for fitness
By definition, nature always purges unhealthy attitudes from the gene pool. And the biggest threat to health in the modern era is not global warming, but people becoming hysterically moralistic about what are complex issues that we have little understanding of. Every purchase, every job, every interaction is judged on some creepy moralistic lense by those who would make the Spanish inquisition look nuanced in contrast to their own nursery-rhyme fanaticism.
Some have become so absolutely certain of their own self-righteous stance to the point of sabotaging themselves and removing themselves from the gene pool. Thank goodness we will be rid of these attitudes in a few generations, and through no violence on the part of the sane. We can simply let them line up and drink the koolaid while the rest of us go about our pragmatic lives, living humbly in understanding that we don't really know what is right or wrong unless it has been proven to promote human flourishing over hundreds of generations. Everything else is speculative and prone to error.
Note that this is not to say people shouldn't be concerned, from a technical or engineering point of view, with various problems facing us, but when you cross the line to turning everything into a hysterical moral stance, that's when knowledge turns into blind faith and becomes toxic.