More than three decades ago, the British economist E. F. Schumacher stated the essence of environmental protection in three words: Small is beautiful. As Schumacher argued in a famous book by that title, man-made disturbances of the natural world—farms, for example, and power plants—should have the smallest possible footprints.
But how can that ideal be realized in a world that must produce more and more food and energy for its growing population? The answer, in just one word this time, is density. Over the course of the last century, human beings have found ways to concentrate crops and energy production within smaller and smaller areas, conserving land while meeting the ever-growing global demand for calories and watts. This approach runs counter to the beliefs of many environmental activists and politicians, whose organic and renewable policies, as nature-friendly as they sound, squander land. The real organizing principle for a green future is density, which not only provides the goods that we need to survive and prosper but also achieves the land-preservation goals of genuine environmentalists.
Food cultivation is an excellent example of the virtues of density. During the second half of the twentieth century, hybrid seeds and synthetic fertilizers, along with better methods of planting and harvesting, produced stunning increases in agricultural productivity. Between 1968 and 2005, global production of all cereal crops doubled, even though the amount of cultivated acreage remained about the same. Indur Goklany, a policy analyst for the U.S. Department of the Interior, estimates that if agriculture had remained at its early-sixties level of productivity, feeding the worlds population in 1998 would have required nearly 8 billion acres of farmland, instead of the 3.7 billion acres that were actually under cultivation. Where in the world—literally—would we have found an extra 4.3 billion acres of land, an area just slightly smaller than South America?
There is an important exception to the historical trend of ever-denser agriculture, however: the production of organic food, which doesnt use many fertilizers and pesticides. Various recent studies have found that land devoted to organic farming produces 50 percent less wheat, 55 percent less asparagus and lettuce, and 23 percent less corn than conventionally farmed land of the same acreage does.
A large-scale transition to organic production therefore makes little sense. In a 2011 essay in Slate, James McWilliams, a history professor at Texas State University and a fearless debunker of the hype over organic food, pointed out that the global population was likely to increase by some 2.3 billion people over the next four decades. So many people, combined with an emerging middle class in developing countries like China and India, would require the worlds farmers to grow at least 70 percent more food than we now produce. The latest figures from the UNs Food and Agriculture Organization (FAO), which showed that the world had little unused arable land, led to an obvious conclusion, McWilliams wrote: Skyrocketing demand for food will have to be met by increasing production on pre-existing acreage. . . . Ninety percent of the additional calories required by midcentury will have to come through higher yields per acre. That is, agriculture must become even denser, producing still more food from the available land. Organic farming would do the reverse.
Inefficient organic production would also undoubtedly increase the cost of food. Thats a particular concern at a time when global food prices are near record highs: last February, the FAO reported that its Food Price Index, a basket of commodities that tracks changes in global food costs, hit its highest level since the organization began documenting prices in 1990. Though food prices have fallen somewhat since then, the Food Price Index throughout 2011 was roughly 60 percent higher than it was back in 2007. Adopting low-density agricultural techniques could also increase deforestation, as farmers desperately seek more farmland—a result that should disturb true environmentalists.
Yet we are continually bombarded with arguments for organic agriculture. In 2010, Maria Rodale—the chairman and CEO of the Rodale Institute, a pro-organic organization—wrote an essay arguing that organic farming was the most effective way to feed the world and mitigate global warming. Organic-friendly grocers, like Whole Foods Market, have seen huge increases in their market share, and industry groups like the Organic Trade Association point out that global sales of organic food and beverages more than doubled, to some $51 billion, between 2003 and 2008.
A related crusade against density is the push for biofuels, which are supposed to help reduce carbon-dioxide emissions but will divert huge blocks of arable land away from food production and into the manufacture of tiny amounts of motor fuel. The leading biofuel at the moment is corn ethanol, whose power density—the amount of energy flow that can be harnessed from a given area of land—is abysmally low. Some energy analysts put it as low as 0.05 watts per square meter of farmland. By comparison, a relatively small natural-gas well that produces just 60,000 cubic feet of gas per day has a power density of 28 watts per square meter; the power density of nuclear plants is even higher.
The power density of ethanol is so low that in 2011, to produce a quantity of motor fuel whose energy equivalent was just 0.6 percent of global oil consumption, the American corn-ethanol sector had to convert a mind-boggling 4.9 billion bushels of grain into ethanol. Thats more corn than the combined outputs of the European Union, Mexico, Argentina, and India. It represents 40 percent of all the corn grown in the United States—about 15 percent of global corn production and 5 percent of all the grain grown in the world. The EU, too, is pushing to produce motor fuel from farmland.
These efforts have, unsurprisingly, driven global food prices upward. In a June 2011 article in Scientific American, Tim Searchinger, a research scholar at the Woodrow Wilson School at Prince- ton University, observed that since 2004 biofuels from crops have almost doubled the rate of growth in global demand for grain and sugar and pushed up the yearly growth in demand for vegetable oil by around 40 percent. We need to consider the moral impact of our actions, Searchinger continued: Our primary obligation is to feed the hungry. Biofuels are undermining our ability to do so. Yet each year, Congress lavishes some $7 billion worth of subsidies on the ethanol industry, and in his January 2011 State of the Union speech, President Obama declared that we can break our dependence on oil with biofuels.
Biofuel enthusiasts, recognizing the moral problems with converting food into fuel, have long promoted cellulosic ethanol, which is derived from inedible biomass, such as switchgrass and trees. In 1976, Amory Lovins, cofounder of the Rocky Mountain Institute and a darling of the Green Left, wrote in Foreign Affairs that exciting developments in the conversion of agricultural, forestry and urban wastes to methanol and other liquid and gaseous fuels now offer practical, economically interesting technologies sufficient to run an efficient U.S. transport sector. Three decades later, not a single company in the United States was producing significant quantities of cellulosic ethanol—yet in 2004, Lovins and several coauthors wrote Winning the Oil Endgame, still clamoring for cellulosic ethanol and even claiming that it would strengthen rural America, boost net farm income by tens of billions of dollars a year, and create more than 750,000 new jobs.
Will it? Cellulosic ethanols power density, though higher than corn ethanols, is nevertheless very low. Even the best-managed tree plantations achieve power densities of only about 1 watt per square meter of cultivated area. That means you need gargantuan quantities of biomass to produce meaningful volumes of motor fuel. Lets say that you wanted to replace just one-tenth of U.S. oil consumption with ethanol derived from switchgrass. That would require you to produce about 425 million tons of switchgrass per year, which would mean cultivating some 36.9 million acres of land—an area roughly the size of Illinois. Put another way: to replace 10 percent of the countrys oil needs with cellulosic ethanol, youd need to plant switchgrass in an area equal to 8 percent of all American cropland currently under cultivation.
Nevertheless, in May 2008, Speaker of the House Nancy Pelosi helped pass a subsidy-packed $307 billion farm bill, declaring it an investment in energy independence because it provided support for the transition to cellulosic ethanol. Under Pelosis leadership, Congress also mandated that fuel suppliers in the United States blend at least 21 billion gallons of cellulosic ethanol into the American gasoline pool by 2022. To reach that standard, Congress set production targets: in 2011, for instance, domestic distilleries would supposedly produce some 250 million gallons of cellulosic ethanol. But the commercial production of cellulosic ethanol remains so insignificant that the Environmental Protection Agency, which administers the governments renewable-fuel rules, was forced to slash the production target to just 6.6 million gallons.
Over the past decade, global energy consumption has increased by about 28 percent. Today, the worlds inhabitants are consuming the equivalent of 240 million barrels of oil per day. We cannot depend on the planets farmland to provide the enormous quantities of energy needed by countries like China, India, Indonesia, and Brazil as millions of their citizens move into the modern economy. We must rely on forms of energy that have the highest density and, therefore, the smallest footprints.
Biofuels arent the only renewable sources of energy whose low power densities make them impractical. Wind turbines have a power density of about 1 watt per square meter. Compare that with the two nuclear reactors at Indian Point in Westchester County, which provide as much as 30 percent of New York Citys electricity. Even if you include the entire footprint of the Indian Point project—about 250 acres—the sites power density exceeds 2,000 watts per square meter. To generate as much electricity as Indian Point does, youd need to pave at least 770 square miles of land with wind turbines, an area slightly smaller than the state of Rhode Island. Further, few people could live on that great expanse of land because the low-frequency sound that wind turbines generate can cause health problems.
Until now, weve examined density chiefly as it relates to area: how much food or energy can be produced on a certain quantity of land. But wind projects defy density in a second way, eating up not just huge tracts of land, relative to their poor performance, but enormous quantities of steel as well. Installing a single wind turbine requires about 200 tons of steel. The newest turbines have capacities of about 4 megawatts. Divide four by 200, and youll find that such a turbine can produce about 0.02 megawatts of electricity per ton of steel. Compare that with a conventional natural-gas-fired turbine—say, General Electrics LM6000. The LM6000 weighs nine tons and can generate nearly 43 megawatts, meaning that it produces about 4.7 megawatts per ton of steel—more than 230 times as many as the wind turbine does.
These numbers are only ballpark figures, of course, and they dont account for the other resources needed to produce electricity. For instance, wind turbines are generally located far from urban areas and require the construction of thousands of miles of high-voltage transmission lines, while gas turbines must be supplied by long steel pipelines carrying methane from distant wells. But even if the calculations are off by a full order of magnitude—and gas-fired generation uses steel merely 23 times as efficiently as wind generation does, rather than 230 times—it remains clear that wind energy production is an enormously resource-intensive process.
Fortunately, opposition to wind projects is growing rapidly. The United States has seen the rise of about 170 anti-wind groups over the past few years. Ontario in Canada alone has more than 50, the European Platform Against Windfarms has 505 signatory organizations from 23 countries, and in the United Kingdom, some 250 anti-wind groups have formed to fight industrial wind projects in Wales, Scotland, and elsewhere. The resistance is easy to understand: people dont want to look at 400-foot-high industrial turbines all day, or at flashing red lights all night, or at unsightly transmission lines.
Environmentalists themselves have begun to recognize the inefficiency of wind turbines. In 2009, the Nature Conservancy, one of Americas most conservative environmental groups, issued a report condemning the energy sprawl that comes with large-scale wind-energy projects. Even hard-core environmental groups like Earth First! have sprung into action. In November 2010, five people, several of them from Earth First!, were arrested for blocking a road leading to a construction site for a 60-megawatt wind project in Maine. According to the Portland Press Herald, one of the protesters carried a sign: STOP THE RAPE OF RURAL MAINE. But politicians have been slower to object to energy sprawl. In March 2010, governors from 29 states implored Congress and the White House to install more wind turbines across the country, arguing that wind energy would reduce electric-sector greenhouse gas emissions by about 25 percent.
The virtues of density can be seen even in nuclear waste. The American commercial nuclear-power industry, over its entire history, has produced about 60,000 tons of high-level waste. Stacked to a depth of about 15 feet, that would cover an area the size of one football field. Coal-fired power plants in the United States, by contrast, generate about 130 million tons of coal ash, much of it contaminated with heavy metals, in a single year. Yes, radioactive waste is toxic and long-lived, but it can be stored safely. France produces about 80 percent of its electricity from nuclear fission, and all of its high-level waste is stored in a single building about the size of a soccer field.
Perhaps the most familiar example of environmentally friendly density, though, is the way humanity has concentrated itself by moving from the country to cities, a process that is happening especially rapidly in the developing world. The opposite process, suburbanization, requires far more land area per resident—and therefore more miles of streets, electricity cables, and sewer lines (see Green Cities, Brown Suburbs, Winter 2009). In a 2009 essay for the Atlantic, architect and author Witold Ryb- czynski wrote that being truly green means returning to the kinds of dense cities and garden suburbs Americans built in the first half of the 20th century.
The greenness of density leads to two conclusions. First, those who make environmental policy should consider density a desirable goal in nearly all the issues that they confront. And second, the real environmentalists arent headline-seeking activists and advocacy groups; theyre farmers, urban planners, agronomists, and, yes, even natural-gas drillers and nuclear engineers.