(Newswire.net — September 19, 2014) — Researchers have long held the view that the number of people on the planet would grow to just 9 billion by 2100, and then stabilize or even decline.
However, according to a report published in Science journal, the latest analysis indicates global population will increase by 4 billion by the end of the century.
“The consensus over the past 20 years or so was that world population, which is currently around 7 billion, would go up to 9 billion and level off, or even decline,” said co-author Adrian Raftery, professor of statistics and of sociology at the University of Washington.
“We found there’s a 70 percent probability the world population will not stabilize this century,” he added.
Much of the reason for the predicted population growth comes from Africa, where the population is expected to quadruple from 1 billion today to 4 billion by 2100.
According to the study,”there is an 80 percent chance that the population in Africa at the end of the century will be between 3.5 and 5.1 billion people.”
Predictions of 4 billion more people on the planet by 2100 places new emphasis on the issue of natural resources, many of which are already dwindling, for example fresh water resources.
According to the United Nations, water use has increased by more than twice the rate of population growth in the last century. By 2025, an estimated two-thirds of the world’s population will live in “water-stressed regions” as a result of overuse, growth and climate change.
Another crucial natural resource is oil. Writing in the prestigious scientific journal, Philosophical Transactions of the Royal Society (‘The Future of Oil Supply’, 2013), experts predicted “a sustained decline in global conventional production appears probable before 2030 and there is significant risk of this beginning before 2020.”
The global population has doubled in 40 years from 1959 (3 billion) to 1999 (6 billion), according to World Population Clock.
Global population is currently increasing at a rate of about 1.14 percent annually, while the average population change is estimated at about 80 million more people per year. It is now estimated that it will take another 43 years to increase by another 50 percent, reaching 9 billion by 2042.
Additionally, by 2030 India’s population is expected to surpass China’s, to become the most populous nation in the world. Meanwhile, Nigeria’s population is predicted to surpass America’s population by around mid-century to become the third-most populous country, reaching about 1 billion people in 2100.
“Earlier projections were strictly based on scenarios, so there was no uncertainty,” said UN demographer Patrick Gerland. “This work provides a more statistically driven assessment that allows us to quantify the predictions, and offer a confidence interval that could be useful in planning.” he added.
The analysis, formulated by UN and researchers at the University of Washington, Seattle, is said to provide a more accurate outlook than other studies in that it incorporates Bayesian statistics, which takes into account many different factors to arrive at a conclusion. It also uses data from the most recent UN population data, released in July.