The world's population was 7 billion in 2011, and it's already set to hit 7.2 billion next month, the UN says in a new report. If that seems like a lot, wait a few more decades: By 2100, the population is projected to be 10.9 billion, AFP reports. Most of the growth is centered in the developing world. In the least-developed countries, population is likely to double from a current 898 million to 1.8 billion in 2050 and 2.9 billion in 2100. In developed countries, the outlook is much different: The UN expects the population to climb from 1.25 billion to 1.28 billion by 2100.
In fact, that figure would actually decline without immigration from poorer areas, likely about 2.4 million people per year from now until 2050, the report says. Half of the world's population growth will be focused on only eight countries: The US, the Democratic Republic of Congo, Ethiopia, India, Niger, Nigeria, Tanzania, and Uganda. Meanwhile, seniors' numbers are growing rapidly. There will be some 3 billion people at least 60 years old by 2100, the report says, more than triple the current figure. The AP adds that life expectancy at birth for the world, which has risen from 47 years in 1950-55 to 69 years in 2005-2010, and is projected to hit 82 years in 2095-2100. Head to AFP for more. (Read more population stories.)