A feature article published by Nature on 19 August synthesises the latest demographic research showing that fertility rates in most of the world have fallen well below the 2.1 births per woman needed to keep populations stable. The Institute for Health Metrics and Evaluation projects that by 2050 more than three-quarters of countries will sit below replacement level, with South Korea’s rate already down to 0.75 and much of Europe locked in a decades-long decline. Researchers warn that shrinking working-age populations could slow innovation and productivity while straining pension and health-care systems as the share of people aged 65 and over in low-fertility nations is forecast to nearly double to 31% within 25 years. Although some governments are experimenting with cash incentives and family-friendly policies, the Nature analysis concludes that even the most aggressive programmes are unlikely to restore birth rates to replacement levels, and urges policymakers to focus on economic resilience and adapting to an older society. The publication has reignited public debate, with tech executive Elon Musk reiterating his view that Europe faces demographic collapse. Demographers quoted by Nature acknowledge the risks but add that gradual adaptation—through immigration, higher labour-force participation and productivity gains—could mitigate the impact of smaller families.