World population to reach 7 billion in 2012

The world's population will reach 7 billion in 2012, even as the global community struggles to satisfy its appetite for natural resources, according to a new government projection.

There are 6.7 billion people in the world today. The United States ranks third, with 304 million, behind China and India, according to projections released Thursday by the Census Bureau.

The world's population surpassed 6 billion in 1999, meaning it will take only 13 years to add a billion people.

By comparison, the number of people didn't reach 1 billion until 1800, said Carl Haub, a demographer at the Population Reference Bureau. It didn't reach 2 billion until 130 years later.

"You can easily see the effect of rapid population growth in developing countries," Haub said.

Haub said that medical and nutritional advances in developing countries led to a population explosion following World War II. Cultural changes are slowly catching up, with more women in developing countries going to school and joining the work force.

That is slowing the growth rate, though it is still high in many countries.

The global population is growing by about 1.2% per year. The Census Bureau projects the growth rate will decline to 0.5% by 2050.

By then, India will have surpassed China as the most populous country.

The Census Bureau updates projections each year on a variety of global demographic trends, including fertility and mortality rates and life expectancy. U.S. life expectancy has surpassed 78 years for the first time, the National Center for Health Statistics announced last week.

The new Census report comes amid record high oil and gasoline prices, fueled in part by growing demand from expanding economies in China and India.

There is no consensus on how many people the Earth can sustain, said William Frey, a demographer at the Brookings Institution, a Washington think tank. He said it depends on how well people manage the Earth's resources.

Today, industrialized nations use a disproportionate share of oil and other resources, while developing countries are fueling population growth.

There are countries in Africa, Asia and the Middle East where the average woman has more than six children in her lifetime. In Mali and Niger, two African nations, women average more than seven children.

"There's still a long way to go in the developing world," Frey said. "A lot of it does have to do with the education of women and the movement of women into the labor force."

In the U.S., women have an average of about two children, which essentially replaces the population. Much of the U.S. population growth comes from immigration.