The more people who freely choose not to have children, the more likely we are heading for a global catastrophe
https://www.bbc.co.uk/news/health-53409521
Non-sense. The reverse is true - the current growth in human population provides the greatest likelihood of global catastrophe, through inadequate basic resources to support that population and climate change.
Why would reduced human population result in global catastrophe - indeed why would the globe be harmed if one species (humans) became extinct. Remember this happens all the time to other species.
But the reality is that people won't stop having children - there is an inherent evolutionary drive to reproduce. The responsible thing for the planet is for people to have less children, to stabilise human global populations and ultimately (sustainably over generations) to gently reduce human populations.