A new report indicates that, in less than two years, global population will reach seven billion people, a number that imposes new challenges for food, health and education. The report also shows that the highest fertility rates are in underdeveloped countries, particularly among the poorest segments of the population.

Despite lower fertility rates in developed countries, the world's population continues to grow, mostly in the planet's poorest countries.  
In less than two years, global population will reach seven billion, according to the Population Reference Bureau, a nonprofit group in Washington DC.

Carl Haub co-authored its report. He says, "At the moment, the world is adding one billion population every 12 years. And it took us until 1800 - however many millions of years that humans have been walking the earth - to reach our first billion."

In Sub-Saharan Africa, birth rates are high and mortality rates have slowed.

Campaigns against killers like HIV-AIDs and Malaria are producing results.

Africa will add one billion people in the next 40 years, according to the report.

"Women in Niger, at today's birth rate, would give birth on average to 7.4 children," Haub said.

Already, 80 percent of the world's children live in Africa and Asia.

This large non-productive segment of the population needs services, schools, health centers and eventually jobs.

"To have a large number of youth who have no education or barely literate is not an advantage," Haub says, "And that I think is one of the biggest challenges facing developing countries."

John F. May is a demographer at the World Bank. He says in Africa only 10 of 100 children will finish secondary school. One percent will go to college. "I think the strength of a country is not linked to the number of people," May says, "but it is linked to the number of educated people."

On the other hand, developed nations have lower birth rates.  Europe and East Asia have the lowest.

Taiwan has the lowest birth rate in the world, an average of one child per woman.  

Higher education and the migration to cities are factors for lower birth rates, May says.

China and India both have over one billion people, the largest populations in the world.  They will soon switch places.

"Sometime in the 2020s which is not that far off, India will become the largest country in population in the world, surpassing China," Haub adds.

Food production continues to be a challenge. However Haub says much of the hunger in the world is not because food is lacking but because people are impoverished. "Half of the population of the developing world lives in what the World Bank defines as extreme poverty: less than $2 per day. And that is the group that is growing faster," Haub said.

Demographers agree that population growth, especially in Africa, will fuel migration to urban areas. As a result, cities could become even more massive, difficult to manage, with large pockets of poverty and slums.