The UN forecasts that India will swell to 1.6 billion people, overtaking China in 2028, just as population there is peaking. Changes in fertility make long-term projections tricky, but the UN reckons that by 2100 the planet’s population will be rising past 10.9 billion, and be much older. The median age will go up from 29 to 41, and around 28% will be over 60. A few may even remember this article.