The United Nations currently predicts that by 2027, India will overtake China as the world’s most populous country. Estimates suggest India and Nigeria will together add 470 million people in the next three decades — almost a quarter of the world’s population increase to 2050. According to a new study from the University of Washington, however, several developing nations may find their so-called demographic dividend much less of a boon than anticipated.
Published in the Lancet, U.W.'s study has improved on the United Nation’s model by modelling fertility differently and making its decline more sensitive to the availability of contraception and the spread of education. In many parts of India, for instance, the total fertility rate — the expected average number of children born to each woman — is already well below the replacement rate of 2.1 and dropping faster than expected. The study, which also tries to account for the feedback loops between education, mortality and migration, concludes that populations around the world are going to start shrinking sooner and faster than projected.
South Asia, for example, would have 600 million fewer people in 2100 than previously predicted thanks to lower-than-expected levels of fertility. Instead of growing throughout, India’s population would peak in 2050 and then decline to 70 percent of that number by the end of the century. By that point, China’s population would be about half its current size. On the other hand, sub-Saharan Africa would continue to grow, with Nigeria entering the 22nd century as the world’s second-largest country, behind India and just ahead of China and Pakistan.