A 2017 scientific study claimed having one fewer child was the most effective way to fight climate change – more impactful than going vegan or ditching your car. A small but growing number of people have consciously chosen not to have children to help the planet. Yet sacrifice may prove unnecessary. After half a century of population explosion and global overpopulation alarms, the problem now appears reversed: population decline. "We're not preparing for what's coming. Just as rapid population growth disrupted the world, the coming population drop will be equally – or more – swift and disruptive", warns Darrell Bricker, Ipsos researcher and co-author (with John Ibbitson) of Empty Planet.