Why is the world aging? Two major distinct trends: Life expectancies have been increasing around the world. 2.Fertility rates have been falling around the world. Bhattacharya,Hyde and Tu-HealthEconomics Bhattacharya, Hyde and Tu – Health Economics Why is the world aging? Two major distinct trends: 1. Life expectancies have been increasing around the world. 2. Fertility rates have been falling around the world