Africa's population is expected to rise from the current 1 billion people to 3.6 billion by 2100, a report released on Wednesday by the UN Population Fund (UNFPA) says.
The report, which relied on recent estimates by UN Population Division, states that Nigeria's population will increase from 390 million in 2050 to 730 million by 2100.
Nigeria will be the third most populous country in the world by 2100, up from its current seventh position.
The report predicts a global population of 9.3 billion in 2050, an increase over earlier figures, and more than 10 billion people by the end of this century.
Much of this increase is expected to come from high fertility countries, which comprises 39 in Africa, nine in Asia, six in Oceania and four in Latin America, the report says.
"The State of the World Population 2011" UNFPA report was published ahead of Oct. 31, which the UN says will mark the birth of the seventh billionth human being into the world.
The UN Correspondent of the News Agency of Nigeria (NAN) reports that seven countries - China, India, U.S, Indonesia, Brazil, Pakistan and Nigeria,- accounts for half of world current seven billion population.
The 126-page UNFPA report notes that Africa's population which is growing by 2.3 per cent a year, is more than double of Asia's one per cent.
Asia remains the most populous major area in the world in the 21st century.
The report warns that demographic pressure posed mighty challenges for easing poverty and conserving the environment.
"This report makes the case that with planning and right investments in people now... our world of 7 billion and beyond can have thriving, sustainable cities, productive labour forces ... and youth populations that contribute to the well being of economies and societies," it says.
The report highlighted the challenges and opportunities individuals would confront- in trying to "build better lives for themselves, their families, communities and nations."
People in nine countries were profiled including: Nigeria, China, Egypt, Ethiopia, Finland, India, Mexico, Mozambique and the former Yugoslav republic of Macedonia.
UNFPA's executive director and Nigeria's former health minister Babatunde Osotimehin said: "Our record population can be viewed in many ways as a success for humanity -- people are living longer, healthier lives.
"How did we become so many? How large a number can our Earth sustain? These are important questions, but perhaps not the right ones for our times.
"When we look only at the big number, we risk being overwhelmed and losing sight of new opportunities to make life better for everyone in the future," Osotimehin said. (NAN)