The world population will reach a new milestone of 7 billion when a baby born on October 31 - somewhere on Earth - will symbolically represent the benchmark, the United Nations said in a report on Wednesday, dpa reported.
"This milestone is a challenge, an opportunity and a call to action," said Babatunde Osotimehin, the executive director of the UN Population Fund (UNFPA) at the launch of the report in London. "It is a wake-up-call, a reminder that we must act now."
The arrival of the 7 billionth person is marked by "achievements, setbacks and paradoxes," according to the report. While birth rates have dropped drastically due to family planning efforts, population numbers keep growing.
On a global average, the birthrate has dropped from six children per woman in 1950 to 2.5 children in 2011.
Osotimehin, a medical doctor and former health minister of Nigeria, said challenges and opportunities awaited the 7 billionth child born on October 31 - an arbitrary date as there is no way of knowing who that child really is.
"That child will be born with an iPhone in its hand, sending tweets. It will be better connected in the world," he said, warning that it faced "the challenges of climate change and urbanization."
"I hope that child will be an innovator and creator to make the world a better place," Osotimehin added.
With 1.8 billion people aged between 10 and 24 globally, fair access to education, resources and opportunities was a main priority, as well as opportunities for women to take charge of their own health, sexuality and family planning issues.
Osotimehin told dpa that he did not condone forced population planning. But he spoke out strongly for the economic and social empowerment of women, which had already led to lower birth rates.
"We must tear down economic, legal, social and cultural barriers to put women and men, and boys and girls, on an equal footing in all spheres of life," the UNFPA chief executive later told a press conference.
"The population question is one of equity, opportunity and social justice," he added.
The report said that, in poor countries, population growth hampers economic development and perpetuates poverty. In rich states, low birth rates mean fewer people pay taxes as their elders retire and expect longer lives.
The report stressed that a stable population was necessary for accelerated, planned economic growth.
It also showed that the global population was paradoxically growing younger - and older - than ever before.
People under 25 already make up 43 per cent of the world population, and up to 60 per cent in some countries. But there are also nearly 900 million people aged over 60, expected to grow to 2.4 billion by mid-century.
It took the world until 1800 to reach its first billion, and until 1987 to reach 5 billion.
The 2011 State of the World Population report focuses on "snapshots" from nine countries: China, Egypt, Ethiopia, Finland, India, Mexico, Mozambique, Nigeria and the former Yugoslav Republic of Macedonia.
Despite the decline of fertility rates, the world has been growing by 80 million people a year - equal to the population of Germany or Ethiopia.
Asia will remain the world's most populous region in the 21st century, with 60 per cent of Earth's people. But Africa is catching up, expected to grow from the current 1 billion - of whom 70 per cent are under 35 - to 3.6 billion by 2100.
The populations in Latin America, Europe and Oceania stand at 1.7 billion people in 2011 and are projected to grow to 2 billion by 2060.
The report noted the need for people to share and sustain the Earth's resources, highlighting two of the world's largest economies: the United States and China.
The US and China use 21 per cent and 24 per cent respectively of the earth's bio-capacity, the report said. The needs of the average American required 9.5 hectares while a person in India or Africa uses just 1 hectare. The global average is 2.7 hectares.