The planet’s population is projected to reach 6.5 billion at 7:16 p.m.
EST Saturday, according to the U.S. Census Bureau and its World
Population Clock.

Thomas Malthus, the 18th-century thinker who famously predicted the
human population would outrun its food supply, would be astounded.

Back in 1798, when Malthus penned his classic An Essay on the Principle of Population, barely a billion Homo sapiens roamed the planet. Today, Earth’s population teeters on the brink of a new milestone: 6.5 billion living, breathing humans.

"Malthus would be astonished not only at the numbers of people, but
at the real prosperity of about a fifth of them and the average
prosperity of most of them," said demographer Joel Cohen, a professor
of populations at Rockefeller and Columbia universities. "He wouldn’t
be surprised at the abject poverty of the lowest quarter or third."

The clock,
which operates continuously, estimates that each second 4.1 people are
born and 1.8 people die. The clock figures are estimates, subject to error, given the difficulties of maintaining an accurate global population count.

However, the key concept — that population levels are growing, but
at a slower rate than in the past few decades — reflects the consensus
view of demographers. The current growth of world population, estimated
by Cohen at 1.1 percent a year, has slowed significantly from its peak
of 2.1 percent annual growth between 1965 and 1970.

"That’s a phenomenal decline," said Cohen, who probed the question of whether population growth is sustainable in his book, How Many People Can Earth Support?. (The short answer: It depends.)

Today, a large portion of the world’s population lives in nations
that are at sub-replacement fertility, meaning the average woman has
fewer than two children in her lifetime. Countries in this camp include
former members of the Soviet Union, Japan and most of Europe.

Demographers attribute the slowing rate of global population growth
in part to more-widespread availability of birth control and to people
in developed nations choosing to have fewer children. But low-birthrate
countries are counterbalanced by nations like Yemen, where the average
woman has seven children in her lifetime.

The highest population growth rates emanate disproportionately from
the poorest regions of Africa, the Middle East and the Indian
subcontinent.

U.S. population is also growing at a steady clip, augmented by high
numbers of immigrants. It is projected to hit 300 million later this
year. Earth’s population is expected to reach 7 billion in 2012,
according to the Census Bureau.

Monthly World population figures:

07/01/05    6,451,058,790
08/01/05    6,457,380,056
09/01/05    6,463,701,322
10/01/05    6,469,818,677
11/01/05    6,476,139,943
12/01/05    6,482,257,297
01/01/06    6,488,578,564
02/01/06    6,494,899,830
03/01/06    6,500,609,361
04/01/06    6,506,930,627
05/01/06    6,513,047,982
06/01/06    6,519,369,248
07/01/06    6,525,486,603