A new report by UNICEF warns that the number of child brides in Africa could more than double to 310 million in the next 35 years.

Though the rates of child marriage are on the decline in most parts of the world, the number of girls married as children in Africa is expected to increase by 250 percent by the year 2050.

At that point Africa would surpass South Asia as the region of the world with the largest number of young women who were married before their 18th birthday, the report says.

The rates of child marriage are technically declining in Africa, but the slow rate of decline combined with an expected population boom means the number of child brides will increase. The report explains that across Africa, the percentage of girls married as children dropped from 44 percent in 1990 to 34 percent today. But because Africa's total population of girls is expected to rise from 275 million today to 465 million by 2050, the sheer growth of the populations will mean higher rates of child marriage.

The report also noted that the progress made in combating child marriages has been unequal, with the poorest girls still facing the same chances of being married as children as they did 25 years ago.

"The data is also clear that ending child marriage requires a much sharper focus on reaching the poorest and most marginalized girls – those in greatest need and at greatest risk – with quality education and a host of other protective services," said UNICEF Executive Director Anthony Lake. "Their lives, and the futures of their communities, are at stake."

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