The Gap Between Delhi and Dallas
In October, just in time for Halloween, the World Wildlife Fund issued its frightening Living Planet Report, which shows that humanity continues to consume resources and destroy ecosystems at a rate that overshoots Earth's ability to produce and restore. And the gap is widening.
This deficit spending cannot last; it will be brought to a halt either by self-restraint or by catastrophe.
The problem, of course, is that international negotiations meant to address the problem generally go something like this: "You've got too many cars!" say poor countries. "Oh yeah? Well, you've got too many people!" say the rich ones.
Energy consumption is perhaps the most divisive issue. The United States, the United Kingdom and Australia together consume more energy each year than India, Pakistan, Japan, China, the Koreas, Southeast Asia and the Pacific Islands combined. Those Asian-Pacific nations have more than 10 times as many people as we do in the U.S., U.K., and Australia, and we use almost 10 times as much energy per head as they do.
History shows that lower population growth usually results from an improved standard of living. But the Wildlife Fund says overall resource consumption must be cut almost in half for the planet to have a fighting chance. Humans are now spending natural resources at a rate equal to 120 percent of Earth's biological capacity. The Wildlife Fund says that we must gradually reduce that figure to about 67 percent by 2050, or risk piling up an "ecological debt" big enough to bankrupt the planet.
Global consumption must be reduced sharply. At the same time, poor nations need to become better off if they're to check their population growth. The implication: Rich nations will have to get by on a lot less.
A 2003 study by Melanie Moses and James Brown in the scientific journal Ecology Letters sharpens the horns of this dilemma. They analyzed data from more than 100 countries and concluded that humans are far from unique among mammals. In fact, we obey a general biological law: The greater the energy consumption by individual animals of a species, the fewer offspring they will produce and raise.
From little monkeys to big apes to prehistoric humans to subsistence farmers to commuters in their SUVs, increases in energy consumption lead to smaller families. (For you math fans, the decline in fertility is proportional to the cube root of per-animal energy consumption.)
A blue whale needs a much bigger vascular system and a lot more energy than does a rabbit to deliver nutrients and oxygen throughout its body. An American toddler, in turn, is hooked up to a support system that dwarfs that of the blue whale: a planet-wide industrial infrastructure.
We humans have the unique ability to extend our "energy networks" far beyond our physical bodies. As we've drawn upon greater quantities of fossil fuels and other resources, we have built societies in which people have education, contraceptives and pension plans, all of which encourage smaller families.
The people of rich nations might like to believe that high consumption has thereby freed them from the laws of nature. But Moses and Brown's analysis says the lunch isn't free: "We hypothesize that parents face a tradeoff between the number of offspring and the energetic investment in each offspring ... the perceived energetic investment (including material goods and education) required for a child to be competitive in a given society is greater in more consumptive societies."
Of course, in biology, no mathematical relationship is absolute. Looking at those nations that deviate from the overall trend can be as instructive as studying those that follow it. For example, birth rates in 10 oil-producing nations whose citizens have unfettered access to fossil fuels are much higher than would be predicted by Moses and Brown's equations. Meanwhile, Cuba, when compared with Central America and the larger nations of the Caribbean, has similar per capita energy consumption but only half the birth rate. Cuba's lower rate of population increase is generally attributed to its high degree of economic equality, a rarity in Latin America.
The generally close relationship between energy consumption and fertility decline, however, suggests that people, like members of all species, tend to keep consuming until, inevitably, they hit a limit. That limit is miserably low if you're a parent living in a Delhi slum; in a Dallas suburb, it's far too high.
If we put these hefty brains of ours to good use, we could become the first species to find a way around Moses and Brown's equations – to restrain both our numbers and our consumption. But on an already battered planet, the solution will require more equality, not more growth.