George Gao, Pew Research, June 8, 2015

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When the English scholar Thomas Malthus published An Essay on the Principle of Population in 1798, the number of people around the world was nearing 1 billion for the first time. “The power of population is indefinitely greater than the power in the earth to produce subsistence for man,” he wrote then.

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In 2015, the global population is an estimated 7.3 billion, according to the United Nations, and many of Malthus’s and Ehrlich’s predictions have yet to come true or have been proven false (such as the “increasing” death rate, which has actually decreased).

According to a pair of 2014 Pew Research Center surveys, however, today’s scientists are more likely than the general American public to be concerned about population growth, though not necessarily to the extent that Malthus and Ehrlich were.

Asked whether or not the growing world population will be a major problem, 59% of Americans agreed it will strain the planet’s natural resources, while 82% of U.S.-based members of the American Association for the Advancement of Science said the same. Just 17% of AAAS scientists and 38% of Americans said population growth won’t be a problem because we will find a way to stretch natural resources.

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Looking ahead, it’s still unclear what the population trajectory will be. The UN says that population will continue to grow throughout the 21st century, predicting with 80% confidence that it will reach somewhere between 9.6 billion and 12.3 billion people by 2100.

Growth is expected to occur mostly in Africa, and abate in the Americas, Europe and parts of Asia, especially as families in more-developed nations have fewer children than they used to have. {snip}

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