If you think we live in a crowded world, think again. World population is expected to grow from 7.3 billion in mid-2015 to 8.5 billion in 2030, 9.7 billion in 2050, and 11.2 billion by 2100, according to new estimates from the United Nations (U.N.). And a population shift is predicted.

At present, China and India are the largest countries in the world, together making up almost 40 pcent of the world's population, while 60 percent of the global population lives in Asia, 16 percent in Africa, 10 percent in Europe, 9 percent in Latin America and the Caribbean, and only 5 percent in North America and Oceania, reports Gulf News. But all that is going to change.

The African continent will claim three of the world's 10 most populous countries in 2050, according to projections released Tuesday by the Population Reference Bureau (PRB) in Washington.

Niger, South Sudan, Democratic Republic of the Congo, Somalia and Chad have the highest fertility rates in the world and are experiencing a baby boom. "The population gains are also due to a decline in mortality rates due to improvements in public health. Africa is going to be a key driver in population growth over the next few decades," said Peter Goldstein, vice president with the PRB, who oversaw production of its 2015 World Population Data Sheet, according to Bloomberg Business.

Populations in 34 countries are projected to be smaller in 2050 than they are now with Japan projected to see the greatest decline with 30 million fewer people living there, reports CNN Money.

While China is currently the world's most populous nation, it will be overtaken by India by 2050, according to PRB. "China for several decades has been focused on driving down fertility rates. India's population is growing at a relatively moderate pace, but China's projected fertility rates will be below replacement level," Goldstein said, according to Bloomberg Business.