According to demographers, the world’s population didn’t reach 1 billion until 1804, and it took 123 years to hit the 2 billion mark in 1927. Then the pace accelerated – 3 billion in 1959, 4 billion in 1974, 5 billion in 1987, 6 billion in 1998.
Looking ahead, the UN projects that the world population will reach 8 billion by 2025, 10 billion by 2083. But the numbers could be much higher or lower, depending on such factors as access to birth control, infant mortality rates and average life expectancy – which has risen from 48 years in 1950 to 69 years today.
“Overall, this is not a cause for alarm – the world has absorbed big gains since 1950,” said John Bongaarts, vice-president of the UN Population Council. But he cautioned that strains are intensifying: rising energy and food prices, environmental stresses, more than 900-million people undernourished.
“For the rich, it’s totally manageable,” Bongaarts said. “It’s the poor, everywhere, who will be hurt the most.”
Many experts believe that most of Africa, and other impoverished nations such as Afghanistan and Pakistan, will be hard-pressed for food, water and jobs for their people, especially in the absence of family planning initiatives.
"Extreme poverty and large families tend to reinforce each other," says Lester Brown, the environmental analyst who heads the Earth Policy Institute in Washington. "The challenge is to intervene in that cycle and accelerate the shift to smaller families."
The executive director of the UN Population Fund, former Nigerian health minister Babatunde Osotimehin, describes the seven billion milestone as a call to action, a time of empowering women in the sense of keeping adolescent girls in school and giving women the control over the number of children they have.