Ecologists worry that the world’s resources come in fixed amounts that will run out, but we have broken through such limits again and again
How many times have you heard that we humans are “using up” the world’s resources, “running out” of oil, “reaching the limits” of the atmosphere’s capacity to cope with pollution or “approaching the carrying capacity” of the land’s ability to support a greater population? The assumption behind all such statements is that there is a fixed amount of stuff—metals, oil, clean air, land—and that we risk exhausting it through our consumption.
“We are using 50% more resources than the Earth can sustainably produce, and unless we change course, that number will grow fast—by 2030, even two planets will not be enough,” says Jim Leape, director general of the World Wide Fund for Nature International (formerly the World Wildlife Fund).
But here’s a peculiar feature of human history: We burst through such limits again and again. After all, as a Saudi oil minister once said, the Stone Age didn’t end for lack of stone. Ecologists call this “niche construction”—that people (and indeed some other animals) can create new opportunities for themselves by making their habitats more productive in some way. Agriculture is the classic example of niche construction: We stopped relying on nature’s bounty and substituted an artificial and much larger bounty.
Economists call the same phenomenon innovation. What frustrates them about ecologists is the latter’s tendency to think in terms of static limits. Ecologists can’t seem to see that when whale oil starts to run out, petroleum is discovered, or that when farm yields flatten, fertilizer comes along, or that when glass fiber is invented, demand for copper falls.
That frustration is heartily reciprocated. Ecologists think that economists espouse a sort of superstitious magic called “markets” or “prices” to avoid confronting the reality of limits to growth. The easiest way to raise a cheer in a conference of ecologists is to make a rude joke about economists.
I have lived among both tribes. I studied various forms of ecology in an academic setting for seven years and then worked at the Economist magazine for eight years. When I was an ecologist (in the academic sense of the word, not the political one, though I also had antinuclear stickers on my car), I very much espoused the carrying-capacity viewpoint—that there were limits to growth. I nowadays lean to the view that there are no limits because we can invent new ways of doing more with less.
This disagreement goes to the heart of many current political issues and explains much about why people disagree about environmental policy. In the climate debate, for example, pessimists see a limit to the atmosphere’s capacity to cope with extra carbon dioxide without rapid warming. So a continuing increase in emissions if economic growth continues will eventually accelerate warming to dangerous rates. But optimists see economic growth leading to technological change that would result in the use of lower-carbon energy. That would allow warming to level off long before it does much harm.
It is striking, for example, that the Intergovernmental Panel on Climate Change’s recent forecast that temperatures would rise by 3.7 to 4.8 degrees Celsius compared with preindustrial levels by 2100 was based on several assumptions: little technological change, an end to the 50-year fall in population growth rates, a tripling (only) of per capita income and not much improvement in the energy efficiency of the economy. Basically, that would mean a world much like today’s but with lots more people burning lots more coal and oil, leading to an increase in emissions. Most economists expect a five- or tenfold increase in income, huge changes in technology and an end to population growth by 2100: not so many more people needing much less carbon.
In 1679, Antonie van Leeuwenhoek, the great Dutch microscopist, estimated that the planet could hold 13.4 billion people, a number that most demographers think we may never reach. Since then, estimates have bounced around between 1 billion and 100 billion, with no sign of converging on an agreed figure.
Economists point out that we keep improving the productivity of each acre of land by applying fertilizer, mechanization, pesticides and irrigation. Further innovation is bound to shift the ceiling upward. Jesse Ausubel at Rockefeller University calculates that the amount of land required to grow a given quantity of food has fallen by 65% over the past 50 years, world-wide.