Enough Is Enough

by Rob Dietz

  Cohen may be critical of predictions, but he has compiled plenty of them in his book, How Many People Can the Earth Support? Although somewhat dated, the book (published in 1995) provides comprehensive coverage of studies on the carrying capacity of the planet. Carrying capacity is defined as the maximum population of an organism that a particular environment can sustain. Having undertaken an exhaustive review of the literature, Cohen found that science-based estimates of the earth’s human carrying capacity range from fewer than 1 billion people to more than 1,000 billion, with the most frequent estimates falling between 4 and 16 billion.4 But he is quick to add that knowledge of population history, population projections, and ecological limits is insufficient to support a confident statement of how many people the planet can sustain.

  The wide range in these estimates stems from the inexact science of calculating carrying capacity. It’s a thorny challenge for an ecolo-gist to gauge the potential population of perch in a pond, gazelles in a grassland, or jaguars in a jungle. Such calculations are tricky despite consistent life cycles and restricted habitats for the species involved. The calculations become even trickier when the species is Homo sapiens. People have spread all over the globe, so our habitats have fuzzier boundaries than those of other species. In addition, people do three things differently than other animals, and these differences make it difficult to pin down our numbers.

  The first difference relates to the quantity of resources we consume. Whereas one sheep consumes about the same amount of stuff as any other sheep, some human individuals, communities, and societies consume a lot more than others (e.g., more food, more materials, and more energy). Our ability to alter how much we consume allows a trade-off between population size and standard of living. We can have a large population consuming relatively meager resources per person or a small population consuming more resources per person. The Worldwatch Institute estimates that the planet could accommodate roughly 13.6 billion people living low-income lifestyles, versus 2.1 billion people living high-income lifestyles (Table 3.1).5 It’s interesting to note that incomes in the high-income scenario are still about $10,000 less per year than the average income in the United States.

  The second trait setting us apart from other animals and hampering determination of human carrying capacity is our ability to trade. Indeed, trade among early peoples may have catalyzed humans’ rise to power. Researchers hypothesize that trade was a uniquely human advancement that allowed us to outcompete the Neanderthals. The thinking is that, through trade, we developed both specialization of labor and new technologies, while Neanderthals (who apparently were reluctant to trade) failed to develop either.6 At the national scale, the flow of goods and services across boundaries—international trade—enables prolonged consumption beyond the capacity of local ecosystems. A nation, therefore, can expand its population and consumption to a greater extent than would be expected given the resources within its own territory.

  TABLE 3.1. POPULATION AND INCOME SCENARIOS

  The third critical difference—the trait that muddles calculations of economic scale and carrying capacity the most—is technology. The unanticipated effects of technology have invalidated the claims of many scholars who have taken a pessimistic stance on the limits to population growth. In the late 1960s, the ecologist Paul Ehrlich expressed grave concern about the prospects for food production to keep pace with the demands of a growing population.7 However, his forecasts of famine failed to materialize in the time frame predicted because he underestimated the speed with which technological breakthroughs in agriculture would be adopted. On the flip side, the promise of technology has led some optimistic analysts to make outlandish assertions. Julian Simon was a rival of Ehrlich’s and an oft-quoted professor of economics and business. In 1996, he claimed that human population could keep growing at the same rate for the next 7 million years—never mind that exponential growth over such a long period would produce a population greater than the number of atoms in the universe!8

  Putting aside predictions for the moment, it’s clear that how much we consume, the effects of trade, and technological progress all influence how many people the planet can support. The story of Norman Borlaug demonstrates the point. Borlaug was a remarkable plant scientist. He directed an agricultural research program in Mexico and, over the course of twenty years, he developed a new strain of high-yield, disease-resistant wheat. He took what he learned and set out on a humanitarian mission to battle hunger by spreading his new strains, coupled with modern farming techniques, around the world. His effort came to be called the Green Revolution, and it prevented famine, suffering, and starvation for masses of people.9 The technology of the Green Revolution and the subsequent trade in food created a caloric cushion that has provided sustenance for a larger global population. But Borlaug himself knew that the cushion was only temporary. In his acceptance speech for the Nobel Peace Prize in 1970, he stated that humanity would lose the fight against hunger unless it could figure out how to limit population size.10

  Even with all the uncertainty attached to estimates of human carrying capacity, most economists, business leaders, government officials, and average Joes and Janes continue to buy into the model of more. They subscribe to technological optimism, a belief in the power of technology to overcome the limits to growth. The idea is that, if we employ technology to decrease the detrimental effects of economic processes, we can keep the numerator in the economic scale relationship from getting too big. But the question remains: how far can technology go in overcoming the failures of economic growth discussed in Chapter 2?

  TECHNOLOGY’S POTENTIAL TO OVERCOME THE LIMITS TO GROWTH

  Tim Jackson is an economist at the University of Surrey. He’s a big-picture thinker who studies the connections between consumption, lifestyles, well-being, and the environment. One of the questions he poses in his research is whether technology can overcome the failures of economic growth. He asks, “Is it really possible for a strategy of ‘growth with decoupling’ to deliver ever-increasing incomes … and yet remain within ecological limits?”11

  The term “decoupling” refers to the process of producing more economic output with fewer material and energy inputs. For decoupling to be a viable strategy, we would need to break the link between economic activity and resource use. The evidence to suggest we can do this, while by no means conclusive, is certainly discouraging. Between 1980 and 2007, the material intensity of the global economy (i.e., the amount of biomass, minerals, and fossil fuels required to produce a dollar of world GDP) decreased by 33 percent. It’s worth celebrating this remarkable improvement in efficiency, as well as the technological innovations that made it possible. And yet, concurrent with these improvements, world GDP grew by 141 percent, such that total resource use still increased by 61 percent (Figure 3.1).12 The gains made in efficiency were overwhelmed by the increase in the size of the economy. The picture is almost identical for global energy use: energy intensity decreased by 29 percent over the same period, but total energy use rose by 70 percent.13 As economist Peter Victor remarks in his book Managing without Growth, “Americans have been more successful decoupling GDP from happiness than in decoupling it from material and energy.”14

  Although efficiency gains have so far failed to counteract the effects of growth, perhaps decoupling could still be a feasible solution for the future. To get a sense of its feasibility, Jackson has calculated the degree of decoupling that would be required in a world where economies continue to grow, and at the same time move toward global equity. Jackson’s scenario assumes wealthy economies will grow at about 2 percent per year between now and 2050, while the economies of poorer nations will grow more quickly, so that incomes in all countries will converge to those of the European Union by 2050. To keep the concentration of atmospheric CO2 at 450 parts per million (a target higher than what many climate scientists believe is safe), the carbon intensity of each dollar would have to decrease by a factor of almost 130—a staggering improvement to achieve.15
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br />   Jackson has also run the numbers out to 2100, and finds that if global economic growth were to continue at 2 percent per year, we would need to achieve “a complete decarbonization of every single dollar.”16 If a stricter CO2 target were imposed (say 350 parts per million instead of 450), Jackson says the carbon intensity would have to be less than zero. In other words, economic activity would have to remove CO2 from the atmosphere, not add to it! These calculations have led him to call decoupling a myth, and to ask a series of thought-provoking questions such as “What kind of economy is that? What are its consumption activities? What are its investment activities? What does it run on?”17

  Maybe there’s still a chance that decoupling can work. Perhaps with major investments in new technologies, we could improve resource efficiency fast enough to offset the negative effects of rising GDP. What if the desired technological breakthroughs are just around the corner? Chris Goodall, a researcher and writer on the topics of climate and technology, asserts that the United Kingdom may have already achieved decoupling of economic growth from overall material use. Based on his analysis of national material flow accounts, he suggests that the weight of material flowing through the U.K. economy peaked around 2001 to 2003, even though the economy continued to grow up until 2007. Goodall concludes that GDP growth may be spurring technological progress and more efficient use of resources, thereby reducing the environmental impacts of economic growth.18

  FIG. 3.1. Although global material intensity (the amount of materials needed to produce each dollar of world GDP) has declined, total material use has increased because of ongoing economic growth. Quantities for world GDP, material use, and material intensity are expressed as percentages of their levels in 1980. SOURCE: see note 12.

  If material use has indeed peaked in the United Kingdom, it’s a striking achievement. However, Goodall offers no evidence of a causal link between GDP growth and improvements in resource efficiency. We think it is far more likely that material use stabilized in spite of GDP growth, not because of it. Moreover, Goodall’s analysis overlooks important indicators, such as CO2 emissions. Taking trade into account, U.K. emissions increased by almost 10 percent between 2001 and 2007.19

  Continued tracking of material use, energy use, and pollution will be necessary to draw stronger conclusions about technology’s role in mitigating the effects of GDP growth, but there are two major reasons to remain suspicious of a “techno-fix decoupling” strategy. The first is the “rebound effect,” which was originally described by William Stanley Jevons in his 1865 book The Coal Question. Jevons observed that the invention of a more efficient steam engine made coal a viable fuel for many new uses. This efficiency gain amplified the demand for coal and led to a major increase in coal consumption, even as the amount of coal required for any particular use fell. As Jevons stated, “It is wholly a confusion of ideas to suppose that the economical use of fuel is equivalent to a diminished consumption. The very contrary is the truth.”20

  New technologies that reduce resource use also reduce costs; this frees up money that can then be spent on additional consumption, often undermining (or sometimes even overtaking) the original efficiency gains. Improvements in automobile fuel efficiency provide a good example. As cars have become more efficient, they have consumed less fuel per mile traveled, and the cost of driving has fallen. But drivers of more efficient cars may use the savings to drive more miles (an example of direct rebound). Alternatively, they might spend this money on a different activity altogether, such as a vacation abroad, increasing overall fuel use (an example of indirect rebound). Either way, because of the rebound effect, material and energy savings predicted on paper often fail to materialize in the real world.21

  The second reason to be skeptical of the techno fix is that although some technologies (such as wastewater treatment) can help alleviate the environmental impacts of growth, others may cause unforeseen pollution and increases in energy and resource use. For example, some of the techniques used in the Green Revolution have caused soil erosion, water pollution, and other undesirable effects. The rapid evolution of computer technology provides another example. Technological progress in the field of miniaturization has vastly reduced the size of computers and expanded their processing power. The change is astounding, and it has provided many tangible benefits. For instance, a modern desktop computer can hold a library’s worth of information. However, the miniaturization enabling this feat has also allowed us to build and operate machines that extract natural resources at rates previously un-imagined. Without the power of modern computers (coupled with an abundance of cheap energy), it is unlikely that mining, fishing, farming, and energy production would be possible at the scale we see today.22

  The key message regarding technological progress is that it can be helpful for managing some of the impacts associated with economic growth, but it may not be sufficient to overcome them. This doesn’t mean that we should discourage innovation or abandon efforts to develop new technologies. On the contrary, we must invest heavily in the infrastructure for a low-carbon economy. But this alone will not be enough. To bring material and energy use within ecological limits, we must address the scale of economic activity as well.

  The starting point may be to reform the education system so that people can gain a better understanding of economic scale. Most introductory economics textbooks devote plenty of ink to “economies of scale” (situations in which a firm can lower its average costs by increasing its output), but they fail to adequately consider sustainable economic scale. In his popular economics textbook, Harvard professor Gregory Mankiw takes less than one out of 896 pages to dismiss the notion that there may be a limit to how large an economy can grow. The conclusion of the passage states, “Market prices give no reason to believe that natural resources are a limit to economic growth.”23 This statement may be true, but it reveals more about the failure of markets than the absence of limits!

  Schools everywhere, from elementary to university, should include a curriculum on scale. To provide a particularly strong grasp of the concept, the curriculum could encourage students to complete a mapping exercise in which they exert their own energy to cross a great distance (a long bike ride down the C&O Canal would suffice for students in the Washington, D.C., area).

  Suppose people did develop a better understanding of economic scale and realized that the economy had grown beyond what’s sustainable. Or suppose that, even if such understanding failed to blossom, people generally concluded that enough was preferable to more. Then a pressing question would arise. What sort of economy provides enough—that is, how would the economy be different from what we’ve experienced in the age of growth?

  [ CHAPTER 4 ]

  WHAT SORT OF ECONOMY PROVIDES ENOUGH?

  It is not enough simply to attack the progrowth orthodoxy; we must have an alternative vision.

  HERMAN DALY1

  Students in college economics courses occasionally express their frustrations, and when they do, it can be both loud and public. Each fall at the University of Pennsylvania, home of the Wharton School of Business, students enrolled in Economics 101 participate in a curious ritual that can fairly be described as loud and public. The night before the first midterm exam, students abandon the library early, even though you’d expect them to linger among the dusty rows of books for one last look at their production-possibility frontiers and supply-and-demand curves. It doesn’t take a reconnaissance team to track down the missing students—they can be found hanging out on the Junior Balcony and grassy field of the lower Quad.

  More and more students make their way to the Quad as the hour approaches midnight. A nervous energy begins to pulse through the crowd, and windows open in the dorm rooms above, so that residents can get a good look at the gathering horde. A minute before midnight, an unsettling quiet descends on the students as they take a collective inward breath. Then the quiet is broken by a countdown, much like the one in Times Square on New Year’s Eve. Ten, nine, eight, seven, …

/>   At the stroke of midnight, the Econ Scream erupts. Normally mild-mannered students hang out of windows screaming, “I HATE ECON!” Members of the crowd, some of them shirtless, scurry in all directions, spewing unintelligible grunts from the depths of their souls. The Econ Scream is an outpouring of emotion and a massive release of stress. A few moments later, the students shuffle back to their dorm rooms, and the Quad rests peacefully for the remainder of the night.

  What causes students to build up and then blow off steam over a simple test of economic knowledge? Mostly it has to do with the pressure accompanying the first exam of their college careers. But there’s more to it than that. After all, it’s not the Math Scream or the English Scream. Students often take exception to economics because they sense a disconnect between what they’re learning and what they experience in the real world.

  The Econ Scream offers a lighthearted example of this attitude among students. A more serious example took place on November 2, 2011, at Harvard University. On that day, seventy students walked out of their economics class, which was being taught by Gregory Mankiw, author of one of the most popular introductory economics textbooks. An open letter from the students to Mankiw stated, “Today, we are walking out of your class, Economics 10, in order to express our discontent with the bias inherent in this introductory economics course. We are deeply concerned about the way that this bias affects students, the University, and our greater society.”2

  The Post-Autistic Economics Movement provides another example of student discontent. In the year 2000, a letter from French economics students to their professors ignited an international uprising. The students wrote the letter to express their dissatisfaction with the teaching of economics and to demand more attention to history, functioning institutions, and concrete realities. They declared, “We no longer want to have this autistic science imposed on us.” As the letter generated media coverage, the movement leapt across the ocean. Students from Cambridge, England, to Cambridge, Massachusetts, identified with the themes of the letter and made similar requests at their colleges.3 The themes are still gaining traction in a journal that emerged from the movement, the Real-World Economics Review.