The Population Bomb: How we survived it

World population will reach 7 billion this year, prompting new concerns about whether the world will soon face a major population crisis.

'In spite of 50 years of the fastest population growth on record, the world did remarkably well in producing enough food and reducing poverty,' said University of Michigan economist David Lam, in his presidential address at the annual meeting of the Population Association of America.

Lam is a professor of economics and a research professor at the U-M Institute for Social Research. The talk is titled 'How the World Survived the Population Bomb: Lessons from 50 Years of Exceptional Demographic History.'

In 1968, when Paul Ehrlich's book, 'The Population Bomb,' triggered alarm about the impact of a rapidly growing world population, growth rates were about 2 percent and world population doubled in the 39 years between 1960 and 1999.

According to Lam, that is something that never happened before and will never happen again.

'There is virtually no question that world population growth rates will continue to decline,' said Lam. 'The rate is only as high as it is because of population momentum, with many women of childbearing ages in developing countries because of rapid population growth in earlier decades.'

Lam discussed a variety of factors that have worked together to reduce the impact of population increases. Among the economic forces, he cited the green revolution, started by Nobel prize-winner Norman Borlaug, that increased per capita world food production by 41 percent between 1960 and 2009.

'We've been through periods of absolutely unprecedented growth rates, and yet food production increased even faster than population and poverty rates fell substantially,' he said.

The capacity of cities to absorb the growth in world population is another major reason that the world was able to double its population in the last 40 years without triggering mass starvation or increased poverty, Lam told the group. Along with urbanisation, Lam pointed to the impact of continued declines in fertility and rising investments in the education and well-being of children.

Work Lam did in Brazil with ISR social demographer Leticia Marteleto shows a mean increase of 4.3 years of schooling among 16-17-year-olds from 1960 to 2000.

'This increase clearly involves more than just reductions in family size,' Lam said. 'For example, children with 10 siblings in 2000 have more schooling than children with one sibling in 1960.

'There is no Norman Borlaug of education to explain how schooling improved so much in developing countries during a period in which the school-age population was often growing at 3 percent or 4 percent a year. This is one of the accomplishments of the last 50 years that deserves to be noted and marvelled about.'

In conclusion, Lam told the group, 'The challenges we face are staggering. But they're really nothing compared to the challenges we faced in the 1960s.'