Shifting population trends mean that one in three children born by 2050 will be African, the U.N. Children's Fund said Tuesday.
UNICEF's new study also says the United States is the only high-income country projected to have an increasing proportion of children by 2025.
The demographic shifts will present policy makers and planners with "major challenges" in the decades following the 2015 deadline for achieving the U.N.'s anti-poverty goals, UNICEF said in a press release.
The study drew its findings from U.N. Population Division projections.
"Though China and India will continue to have a major share of the world's population, in absolute terms, Nigeria will see the highest increase in its under-18 population of any country, adding 31 million children, a rise of 41 per cent, between 2010 and 2025," the study says.
The study adds that the deaths of children under age 5 will increasingly occur in sub-Saharan Africa, particularly in pockets of poverty and marginalization in heavily populated, low-income countries.
Co-author Danzhen You highlighted the need to safeguard children's rights, especially as the aging global population increases pressure to shift resources away from children.
"Children do not vote," You said. "Their voices are often not heard when governments make decisions about funding."
According to projections, the 49 U.N.-designated Least Developed Countries will account for around 455 million of the two billion global births between 2010 and 2025. Five populous middle-income countries—China, India, Indonesia, Pakistan and Nigeria—will account for about 859 million births between 2010 and 2025.
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