Towards the gerontocene?

All statistics concur: total fertility rates are falling across the world. Knowing that a population is stable with 2.1 children per woman, fertility rates worldwide have dropped from 5 children in the 1960s to around 2.5 in 2015 (World Bank 2015). Such statistics suggest that fertility rates will remain above the 2.1 threshold for the foreseeable future, which means that world population should keep increasing in the foreseeable future.