Population Equation: Balancing What We Need With What We Have

Planet Earth, now home to about 6.5 billion human beings, has thus far disproved the doomsayers. In 1798, Rev. Thomas Robert Malthus predicted that population would outrun food supply on the assumption that human numbers would increase at a geometric rate while food would be limited to arithmetic increases. Then, in 1968, Stanford University professor Paul R. Ehrlich issued a similar warning in his book The Population Bomb, in which he predicted that hundreds of millions of people would die of starvation in the 1970s and 1980s. Both men underestimated humanity’s resourcefulness—as well as its scientific and technological acumen—in figuring out how to provide for its growing numbers. Still, there’s little doubt that the Earth’s human carrying capacity has a limit. And growth can’t continue indefinitely without more of the significant environmental health impacts we are already seeing. In addition to documenting exactly how much growth is occurring, scientists are now interested in trends reflecting where such growth is occurring and the effect of factors such as consumption rates and migration on sustainability of the Earth’s resources.