The United Nations Population Fund estimates that the world’s population will top 7 billion today, having doubled in size since 1968.
The astonishing growth comes at a time when fertility rates have plummeted worldwide. But advances in medicine have resulted in markedly longer lifespans — from 48 in the 1950s to 69 in the first decade of this century — and a precipitous drop in infant mortality rates.
Though 43 percent of the world’s population is under the age of 25, a ballooning number of elderly inhabitants will present the planet with new challenges. Today, there are just under 900 million people over age 60, but by the middle of this century, that number is expected to rise to 2.4 billion.
China remains the world’s most populous country, with 1.35 billion inhabitants, but India is expected to claim the top slot by 2025, reaching a population of 1.6 billion.
THE WORLD'S 10 MOST POPULOUS COUNTRIES IN 2010
1. China 1.34 billion
2. India 1,22 billion
3. United States 310 million
4. Indonesia 240 million
5. Brazil 195 million
6. Pakistan 174 million
7. Nigeria 158 million
8. Bangladesh 149 million
9. Russia 143 million
10. Japan 127 million
COUNTRIES WITH THE HIGHEST BIRTH RATES PER 1,000 WOMEN
1. Niger 50.54
2. Uganda 47.49
3. Mali 45.62
4. Zambia 44.08
5. Burkina Faso 43.59
COUNTRIES, TERRITORIES WITH FEWEST BIRTH RATES PER 1,000 WOMEN
217. St. Pierre and Miquelon 8.32
218. Germany 8.30
219. Hong Kong 7.49
220. Japan 7.31
221. Monaco 6.94
* United States ranks 148th with 13.83 births per 1,000 women
FACTS
About 80 million people are added to the world each year, a number roughly equivalent to the population of Germany or Ethiopia.
People under the age of 25 make up 43 percent of the world’s population, reaching as much as 60 percent in some countries.
Source: “State of World Population 2011,” by The United Nations Population Fund
Video by Karan Singh, Jasvinder Singh, Shalini Sharma, Olivia Linn