Humanities › Geography The Most Populous Countries in 2100 Share Flipboard Email Print New Delhi, India. hadynyah/Getty Images Geography Population Basics Physical Geography Political Geography Country Information Key Figures & Milestones Maps Urban Geography by Matt Rosenberg Matt Rosenberg is a professional geographer and writer with over 20 years of experience. He is the author of both a geography reference book and a guide to winning National Geography Bee contests. Updated January 16, 2019 In 2017, the United Nations Population Division released its World Population Prospects: The 2017 Revision, a set of population projections out to the year 2100 for the planet Earth and for individual countries. The United Nations expects the global population— 7.6 billion as of 2017—to reach 11.2 billion by the year 2100. The report placed current population growth at 83 million people per year. Key Takeaways: The Most Populous Countries in 2100 • The U.N. expects the current global population of 7.6 billion to reach 11.2 billion in 2100.• Most population growth is expected to take place in a small group of countries, including India, Nigeria, the United States, and Tanzania. In many other parts of the globe, fertility rates are declining, and populations are expected to see little or negative growth.• Migration—driven by the effects of climate change and other challenges—is expected to play a larger role in demographic changes over the next century. The United Nations looked at population growth both globally and at the country level. Of the 10 largest countries, Nigeria is growing the fastest and is expected to have a population of nearly 800 million by 2100, making it even larger than the United States. By 2100, the U.N. predicts that only India and China will be larger than Nigeria. The Most Populous Countries in 2100 Current population growth varies wildly from country to country, and the list of the most populous nations in the world is expected to look much different by the turn of the next century. Ranking Country 2100 Population Current Population (2018) 1 India 1,516,597,380 1,354,051,854 2 China 1,020,665,216 1,415,045,928 3 Nigeria 793,942,316 195,875,237 4 United States 447,483,156 326,766,748 5 Democratic Republic of the Congo 378,975,244 84,004,989 6 Pakistan 351,942,931 200,813,818 7 Indonesia 306,025,532 266,794,980 8 Tanzania 303,831,815 59,091,392 9 Ethiopia 249,529,919 107,534,882 10 Uganda 213,758,214 44,270,563 These U.N. projections are based on national censuses and survey data from around the world. They were compiled by the Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat. The full data is available for download in a customized Excel spreadsheet. Compared to current population estimates and 2050 population projections, note the high number of African countries on this list (five out of the top 10). While population growth rates are expected to decline in most countries in the world, African countries by 2100 may not experience much reduction in population growth at all. Even some countries whose growth rates are expected to decline will still become much larger, as their growth rates are already relatively high. Most notably, Nigeria is expected to become the third most populous country in the world, a spot long held by the United States of America. Of the five most populous nations in 2100, five are expected to be African countries. About half of the world's population growth over the next 30 years is expected to take place in only nine countries: India, Nigeria, the Congo, Pakistan, Ethiopia, Tanzania, the United States, Uganda, and Indonesia. Reasons for Population Growth In developed nations around the world—including England, France, and Japan—fertility rates are declining, reducing overall population growth. However, some of the decline in growth is being mitigated by longer life expectancies, which have risen to 69 years for men and 73 years for women. The global increase in life expectancies is due to multiple factors, including a reduction in child mortality rates and improved treatment for HIV/AIDS and other diseases. In most developed nations, populations are expected to see minimal or negative growth over the next century. Diminished fertility rates will result in aging populations, with people over the age of 60 making up about 35 percent of Europe's population (they currently make up only 25 percent). Meanwhile, the number of people over the age of 80 is expected to increase as well. By 2100, the U.N. predicts there will be about 900 million people in this age cohort around the globe, nearly seven times as many as there are now. Another reason for shifting populations, the U.N. notes, is migration, and the Syrian refugee crisis, in particular, is expected to substantially increase the populations of Syria's neighbors, including Turkey, Jordan, and Lebanon. Migration is also expected to take place in other parts of the globe, much of it driven by the effects of climate change. As rising temperatures disrupt ecosystems and increase food insecurity, more and more populations will be displaced, causing demographic changes in affected areas. A 2018 report by the World Bank found that worsening climate change could cause more than 140 million people to become "climate migrants" by 2050. Continue Reading In the Year 2050, Which Countries Will Have the Most People? What Is India's Population? China's One-Child Policy Had a Huge Impact on Population Growth Can You Name the 30 Largest Cities in the World? 10 Fascinating Facts About Africa Top 25 Most Populous Countries in the World Current World Population and Future Projections Which State Has the Biggest Population? Here's How Much Info One Basic Graph Can Show About a Population Ranking the 7 Continents by Size and Population How to Measure and Understand Population Growth Is Population Growth Creating Serious Environmental Issues? Why Is Negative Population Growth Important? Russia Expected to Lose 32 Million People by 2050 What Is Latin America? Definition and List of Countries What Is the Population of the United States?