For years, experts have suggested that the human population is growing at a startling rate. But it might be accelerating at an even greater rate than previous predictions.

According to a new report by the Population Reference Bureau (PRB), the world's population could swell to 9.9 billion by 2050.

There are an estimated 7.6 billion people on the planet today, so when you do the math, the global population could be 33 percent larger in 35 years than it is today.

That prediction is bigger than the most recent estimates in the United Nations report, which suggested the world's population would reach 9.6 billion by 2050.

There are a few reasons why the world's population is growing so rapidly. For one, people are living longer than at any other point in history, thanks to advances in healthcare, nutrition, and access to food.

The UN report also adds that more people survive to reproductive age and there is increased migration to safer, more developed areas.

The region with the most rapid population growth within the next 35 years is expected to be Africa, according to the PRB report. Nigeria's population, for example, is projected to double by 2050.

The UN report also backs up these findings.

"More than half of global population growth between now and 2050 is expected to occur in Africa," the UN reported in 2015.

"Of the additional 2.4 billion people projected to be added to the global population between 2015 and 2050, 1.3 billion will be added in Africa."

Rapid population growth may pose challenges for future generations, including scarcities of resources like clean water and food.

With all those added people, it might really be time to start thinking about how humans could move to Mars.

This article was originally published by Business Insider.

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