The world’s current population of 7.3 billion people will reach up to 9.7 billion by 2050 and 11.2 billion by 2100, says John R. Wilmoth, director of the United Nations Population Division.

Speaking at Seattle’s annual Joint Statistical Meeting Monday, Mr. Wilmoth said the world population is estimated to reach between 9.5 and 13.3 billion by the end of the century.

“The projections stand in stark contrast to a widely held idea that the human population would peak in 2050 at about 9 billion,” writes The Christian Science Monitor’s Pete Spotts the first time the UN floated the possibility of hitting 11 billion people by the end of the century.

There is roughly a 23 percent chance that the world’s population will stop growing within this century, the UN says.

Population experts predict the main factor behind the rise is a projected increase in Africa’s population. Today, the continent hosts 1.2 billion people, but that number will likely reach between 3.4 billion and 5.6 billion people by 2100.

The continent’s population will continue to soar unless fertility rates decline in sub-Saharan Africa, where some areas’ populations are growing at an exceedingly rapid rate.

“Yet this is where some of the poorest countries on the planet are – where energy demand will grow with development and where the effects of climate change will tax economies lacking the resources to effectively adapt,” Mr. Spotts said.

The strain of unbridled population growth on the planet's finite resources comes into sharp focus this week as the planet approaches the so-called Earth Overshoot Day – the day when the world's population uses up all the natural resources the Earth can generate in a single year as defined by the sustainability think tank, Global Footprint Network.

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“This overshoot leads to a depletion of Earth’s life-supporting natural capital and a buildup of carbon dioxide in the atmosphere,” reads the Overshootday.com website. The Global Footprint Network estimates that the current population demands the resources of 1.6 Earths.

With global population numbers on the rise, “it means we still seem to be heading fast in the wrong direction with the world gearing up to approve new sustainable development goals in New York, and a new climate accord in Paris,” reports The Guardian.