USA, October 31, 2011 (CNN): The global population is expected to reach 7 billion today — just 12 years after hitting 6 billion — and the milestone has many pondering the complex challenges associated with billions more people on Earth in the coming years. Some are also pondering something else: Just how big is 7 billion really? It’s a number that’s easy to underestimate.
“The number is just outside of our usual everyday scale of thinking,” said Klaus Volpert, an associate professor of mathematics at Villanova University. “Once you go past a million, it becomes a blur.”
Here are some different ways that might help you envision the enormousness of 7 billion:
::: Seven billion seconds ago, the year was 1789. That was the year George Washington was inaugurated as the first U.S. president and Congress met for the very first time.
::: Seven billion ants, at an average of 3 milligrams each, would weigh at least 23 tons (46,297 pounds).
The world didn’t reach 1 billion inhabitants until 1800, according to the Population Reference Bureau, and it reached 2 billion in 1930. But with advances in modern medicine, in 1960 it reached 3 billion; in 1974, 4 billion; in 1987, 5 billion; and in 1999, only 12 years ago, it reached 6 billion.
The U.N. has estimated a population of 9.3 billion by 2050, and there is expected to be more than 10 billion people on Earth by 2100.
“We’re getting into more and more trouble the bigger the number gets,” said John Bongaarts, vice president of the Population Council, an international nonprofit group. “Every billion people we add makes life more difficult for everybody that’s already here.”