This is misleading. Birth rates globally are still above replacement level. Even if they weren't, immigration still provides opportunities for people to move from areas of higher relative birth rate to areas of lower relative rate, should they choose to.
it's not really misleading at all. Places like Vietnam, the Philippines, Thailand, India, Bangladesh, and Malaysia all had birth rates below replacement in 2021.
Sure, you can still find nice big numbers in places like Niger in sub-saharan Africa, but even they are starting a sharp decline. And they are starting with a low base. Their entire national population is only the size of the greater NYC area.
