World Population: Fertility Surprise Implies More Populous Future

Robert Engelman | Jul 10, 2013

World population reached 7.2 billion in mid-2013, according to United Nations demographers, with present and projected future growth propelled in part by unexpectedly high fertility in a number of developing countries.1 Based on current trends in global birth, death, and migration rates, the United Nations projects a variety of future population scenarios, with the three principal ones suggesting that world population will be somewhere between 6.8 billion and 16.6 billion at the end of this century.2 (See Figure 1.) Using a number based literally on a projection of trends through 2010, the U.N. demographers determined that 82.1 million people were added to the world’s population in 2012—the highest annual increment since 1994.3 (See Figure 2.)

 World Population Figure 1


Based in large part on the 2010 round of annual censuses in countries around the world, the new U.N. Population Division report, World Population Prospects: The 2012 Revision, dispels a widespread view that experts expect population growth to end “on its own” sometime in the second half of the twenty-first century.4 Rather, the new medium-fertility or best-guess scenario suggests the most likely outcome is that world population will continue to grow throughout this century and into the next. In this scenario, the world still gains more than 10 million people in the year 2100 and closes the century at 10.9 billion.5

By 2050, the year when many in the environmental and food security fields had been assuming the world will be home to around 9 billion human beings, the new projections suggest instead a global population of 9.6 billion.6 That is about 700 million people more than the 8.9 billion the U.N. Population Division had projected for 2050 just 10 years ago.7

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