Around the world, babies born Monday are being noted as symbolically bringing the world human population up to 7 billion people. The United Nations is marking the event with celebrations and festivities around the world, as part of the U.N.'s 7 Billion Actions initiative.
The program is meant to encourage action and communication around issues of population growth, international understanding, and environmental sustainability. "A world of seven billion has implications for sustainability, urbanization, access to health services and youth empowerment – however, it also offers a rare call-to-action opportunity to renew global commitment for a healthy and sustainable world," the U.N. website says.
Demographers say it took until 1804 for the world to reach its first billion people, and a century more until it hit 2 billion in 1927. The twentieth century, though, saw things begin to cascade: 3 billion in 1959; 4 billion in 1974; 5 billion in 1987; 6 billion in 1998.
The U.N. estimates the world's population will reach 8 billion by 2025 and 10 billion by 2083. But the numbers could vary widely, depending on everything from life expectancy to access to birth control to infant mortality rates.
(image via: http://people.howstuffworks.com/)