When assessing the adequacy of basic resources such as land or water over time, population is the universal denominator: as population expands, per capita availability shrinks.
The world population took until the start of the 19th century to reach 1 billion people. As population growth has picked up momentum, we have passed new milestones much more quickly. In 2011, the world reached 7 billion.
Tonight 219,000 people will be at the dinner table who were not there last night—many of them with empty plates.
While world population growth has slowed from the peak of 2.1 percent in 1967 to 1.1 percent in 2014, the global population is still projected to grow to 9.5 billion by 2050.
With populations stabilizing in much of the industrial world, almost all population growth in the near future is expected to occur in developing countries.
As human populations grow, so typically do livestock populations.
Nigeria, geographically not much larger than Texas, now has 178 million people and is projected to double by 2041, reaching 440 million in 2050.
Ethiopia, one of the hungriest countries, could grow from 96 million to 188 million by 2050.
Pakistan, with 185 million people living on the equivalent of 8 percent of the U.S. land area, is projected to reach 271 million by 2050—nearly as many people as in the United States today.
More than 200 million women around the world like to prevent or delay pregnancy but lack access to family planning information or effective contraception.
Iran experienced one of the fastest rates of fertility decline in world history, dropping growth from 4.1 percent in 1985 to 1.3 percent in 1995 by supporting education and family planning.
Worldwide 44 countries, including nearly all those in both Western and Eastern Europe, have reached population stability as a result of gradual fertility decline over the last several generations.
Updated July 2014