The majority of those moving to cities-especially in developing countries-do so to earn higher incomes. Even though income inequalities have been increasing within most countries, on a global basis, there has simultaneously been a historic movement of people out of poverty and into the middle cla.s.s-particularly in Asia. And the vast majority of the growing global middle cla.s.s will live in cities.

Already, more than 80 percent of global production takes place in cities. The per capita carbon emissions of people who live in cities are lower than that of people who live in suburbs, but in spite of the improved efficiency with which resources are used in cities, the overall per capita consumption rates in cities are significantly higher than in rural areas-primarily because incomes are higher.

In just the last thirty years, per capita consumption of meat in developing countries has doubled, while egg consumption has quintupled. The impact of skyrocketing meat consumption on topsoil, deforestation, and freshwater resources-and its production of global warming pollution and cardiovascular disease-is magnified by another factor as well: nine kilograms of plant protein are consumed in the production of one kilogram of meat protein.

HUNGER AND OBESITY.

The change in diets around the world is also creating a global obesity epidemic-and in its wake a global diabetes epidemic-even as more than 900 million people in the world still suffer from chronic hunger. In the United States, where many global trends begin, the weight of the average American has increased by approximately twenty pounds in the last forty years. A recent study projects that half the adult population of the United States will be obese by 2030, with one quarter of them "severely obese."

At a time when hunger and malnutrition are continuing at still grossly unacceptable levels in poor countries around the world (and in some pockets within developed countries), few have missed the irony that simultaneously obesity is at record levels in developed countries and growing in many developing countries.

How could this be? Well, first of all, it is encouraging to note that the world community has been slowly but steadily decreasing the number of people suffering from chronic hunger.

Secondly, on a global basis, obesity has more than doubled in the last thirty years. According to the World Health Organization, almost 1.5 billion adults above the age of twenty are overweight, and more than a third of them are cla.s.sified as obese. Two thirds of the world's population now live in countries where more people die from conditions related to being obese and overweight than from conditions related to being underweight.

Obesity represents a major risk factor for the world's leading cause of death-cardiovascular diseases, princ.i.p.ally heart disease and stroke-and is the major risk factor for diabetes, which has now become the first global pandemic involving a noncommunicable disease.* Adults with diabetes are two to four times more likely to suffer heart disease or a stroke, and approximately two thirds of those suffering from diabetes die from either stroke or heart disease.

The tragic increase in obesity among children is particularly troubling; almost 17 percent of U.S. children are obese today, as are almost 7 percent of all children in the world. One respected study indicates that 77 percent of obese children will suffer from obesity as adults. If there is any good news in the latest statistics, it is that the prevalence of obesity in the U.S. appears to be reaching a plateau, though the increases in childhood obesity ensure that the epidemic will continue to grow in the future, both in the U.S. and globally.

The causes of this surge in obesity are both simple-in that people are eating too much and exercising too little-and complex, because the manufacturing and marketing of food products has changed dramatically. Dr. David Kessler, former head of the U.S. Food and Drug Administration, has extensively doc.u.mented how food manufacturers and restaurant and fast food chains carefully combine fats, sugar, and salt in precise ratios that reach the "bliss point"-which means they trigger brain systems that increase the desire to eat more, even after our stomachs are full. On a global basis, the World Health Organization has found a pattern of increased consumption of "energy-dense foods that are high in fat, salt and sugars but low in vitamins, minerals and other micronutrients."

Hyper-urbanization has separated more people from reliable sources of fresh fruit and vegetables. Quality calories in fruits and vegetables now cost ten times as much as calories per gram in sweets and foods abundant in starch. In a report for the Johns Hopkins Bloomberg School of Public Health, Arielle Traub doc.u.mented the increase from 1985 to 2000 in the price of fresh fruits and vegetables by 40 percent, while prices of fats declined by 15 percent and sugared soft drinks by 25 percent. Relative price, limitation of access to healthy food, increased inactivity, and the c.u.mulative effects of ma.s.sive food advertising campaigns all contribute to the obesity epidemic.

Several studies indicate that low-income neighborhoods have less access to supermarkets with a selection of fresh fruits and vegetables and are more likely to have fast food chains and convenience stores selling Slim Jims and Big Gulps than middle- and higher-income neighborhoods. Relative income and the time and knowledge necessary for food preparation both also play a role. Once eating habits are established, they are harder to change. When the U.S. government introduced healthier foods into the school lunch program in 2012, students at many schools launched protests on social media and threw the healthier food away.

In many countries, there is an almost precise correlation between the introduction of American fast food outlets and climbing obesity rates. One of the factors that led to the surge in fast food, manufactured food, and increasing portion sizes was a historic change in U.S. agricultural policy in the 1970s, at exactly the time when obesity rates began their climb. Instead of compensating farmers to withdraw land from production, as had been the case since FDR's New Deal, the government subsidized farmers to grow as much as they possibly could. This policy change coincided with new advances in agriculture technology, including better hybrid seeds coming out of the Green Revolution. Consequently, food prices went down significantly. Dr. Carson Chow, a mathematician working at the National Inst.i.tute of Diabetes and Digestive and Kidney Diseases, constructed a detailed mathematical model that strongly suggests that the changes in U.S. agricultural policy correlate precisely with the large average weight gains and increased obesity.

The advertising industry has played a major role. One fast food hamburger chain, to pick only one example, famously used in its television advertis.e.m.e.nts a skimpily clad s.e.x symbol washing a car in a suggestive manner. The advertising budget for manufactured food items and fast food chains is already two thirds that for automobiles. And again, these interrelated trends may have started in the U.S., but have now spread around the world. The impact of obesity on the world's resources is the equivalent of adding an extra one billion people to the planet.

THE ORIGINS OF Ma.s.s MARKETING.

The rising rate of consumption in the world is a relatively new phenomenon, less than a century old, and is also a trend that started in the United States. Although ma.s.s advertising began to emerge in the late nineteenth and early twentieth centuries, most historians date the true beginning of consumer culture to the 1920s, when the first ma.s.s electronic medium, radio, was introduced in the United States, along with the first national circulation magazines and the first silent films shown in theaters. Significantly, consumer credit also became more widely available during the Roaring Twenties to help buyers finance the purchase of relatively expensive new products like automobiles and radios.

Electricity, which was available in less than one percent of American households at the beginning of the twentieth century, rose to almost 70 percent of U.S. homes by the end of the 1920s. The technology of ma.s.s production with interchangeable parts and early forms of automation (all forerunners of today's Earth Inc.) began to decouple productivity from increased employment and produced a cornucopia of consumer goods that stimulated a keen interest among manufacturers and merchants in the emerging science of ma.s.s marketing. The advertising industry entered a new and distinctly different role in the marketplace.

It was at precisely this moment in history that the ideas of Sigmund Freud became popular in the United States. Freud's first trip to America was in 1909, to deliver a series of five lectures on psychoa.n.a.lysis at Clark University in Worcester, Ma.s.sachusetts, to an audience that included William James (whose young protege, Walter Lippmann, was greatly influenced by Freud) and many of the other most prominent intellectuals in America. Throughout the following decade, ideas popularized by Freud-like the role of the subconscious in understanding human motivation, psychological transference, and other insights from psychoa.n.a.lysis-spread, particularly on the East Coast, where the advertising industry was and is located. The American Psychoa.n.a.lytic Society was founded two years after Freud's visit.

By the time the United States entered World War I in 1917, these psychological concepts had been adapted into techniques of ma.s.s persuasion that were used during the war effort. Woodrow Wilson established a Committee on Public Information. Sigmund Freud's nephew, Edward Bernays, served on the committee, alongside Walter Lippmann, only two years his elder, whose influence on Bernays almost rivaled that of his uncle Sigmund. After the war, Bernays p.r.o.nounced himself astonished at the effectiveness of ma.s.s propaganda and set out to introduce the techniques into ma.s.s marketing.

Known as the "father of public relations," Bernays actually coined the phrase "public relations" in order to avoid using the word "propaganda," which had acquired a negative connotation in the U.S. due to its frequent use by Germany to describe its ma.s.s communications strategy during the war. Bernays revolutionized the field of marketing research by discarding the then standard technique of asking consumers what they liked and disliked about various products. Instead, Bernays spent time with psychoa.n.a.lysts and conducted deep interviews with people designed to uncover the a.s.sociations they made in their subconscious minds that might be relevant to the marketing of products and brands. Bernays's business partner, Paul Mazur, said, "We must shift America from a needs to a desires culture.... People must be trained to desire, to want new things, even before the old have been entirely consumed. We must shape a new mentality. Man's desires must overshadow his needs."

As Bernays later wrote, in 1928, the conscious and intelligent manipulation of the organized habits and opinions of the ma.s.ses is an important element in democratic society. Those who manipulate this unseen mechanism of society const.i.tute an invisible government that is the true ruling power of this country. We are governed, our minds molded, our tastes formed, our ideas suggested, largely by men we have never heard of. This is a logical result of the way in which our democratic society is organized.... In almost every act of our daily lives, whether in the sphere of politics or business, in our social conduct or our ethical thinking, we are dominated by the relatively small number of persons ... who understand the mental processes and social patterns of the ma.s.ses. It is they who pull the wires which control the public mind.

In one of his early successes, Bernays tackled a problem for his client, the American Tobacco Company: how could he break down the social taboo against women smoking cigarettes? He hired a group of women to dress as suffragettes and march in formation in a parade down Fifth Avenue in New York City on Easter Sunday, 1929. When they reached the section of elevated seats reserved for the press, the faux suffragettes all pulled out cigarettes, lit them up, and proclaimed them to be "freedom torches." Decades later, the iconic cigarette advertis.e.m.e.nt aimed at women-"You've come a long way baby"-was still using Bernays's innovative but sinister a.s.sociation of smoking with women's rights.

In 1927, a prominent American business advisor, Edward Cowdrick, wrote that stimulating consumption had become more important than production: "the worker has come to be more important as a consumer than he is as a producer ... not to manufacture and mine and raise enough goods, but to find enough people who will buy them-this is the vital problem of business." He described this fresh macroeconomic conventional wisdom as the "new economic gospel of consumption."

His use of the word "gospel" was not as casual as it may sound today. The struggle between capitalism and communism had taken on a new significance in the wake of Lenin's successful revolution in Russia ten years earlier and the establishment of the USSR. During the long struggle between capitalism and communism in the twentieth century, unlimited growth was the one a.s.sumption built into both ideologies that neither questioned.

In 1926, President Calvin Coolidge in a speech to advertisers ventured into the same sacred territory that Cowdrick had described as a new economic gospel: "Advertising ministers to the spiritual side of trade. It is a great power that has been entrusted to your keeping which charges you with the high responsibility of inspiring and enn.o.bling the commercial world. It is all part of the greater work of regeneration and redemption of mankind."

Three years later, two months before the stock market crash of 1929, Coolidge's successor as president, Herbert Hoover, issued the report of his Committee on Recent Economic Changes, which took note of the newly recognized power of psychology in ma.s.s marketing: "The survey has proved conclusively what has long been held theoretically to be true, that wants are almost insatiable; that one want satisfied makes way for another. The conclusion is that economically, we have a boundless field before us; that there are new wants that will make way endlessly for newer wants, as fast as they are satisfied ... by advertising and other promotional devices, by scientific fact finding, by a carefully predeveloped consumption a measurable pull on production has been created ... it would seem that we can go on with increasing activity."

In the 1930s, another Freudian psychoa.n.a.lyst from Vienna, Ernest Dichter, immigrated to the U.S. and began working on ma.s.s marketing. Fully aware of the popularity of Freudian concepts in the advertising business, he told potential customers on Madison Avenue and Wall Street that he was not only a "psychologist from Vienna" but that he had lived on the very same street as Sigmund Freud. He promised them that he could help them "sell more and communicate better." And, like President Coolidge, he saw the importance of stimulating more ma.s.s consumption as a means of strengthening America's economy in the struggle to ensure the triumph of capitalism. "To some extent the needs and wants of people have to be continuously stirred up," Dichter said.

Inevitably, the new power of psychology-based ma.s.s electronic marketing had an enormous impact on the democracy sphere as well as the market sphere. Bernays and Lippmann had both always predicted it would. But in the desperate and dangerous interwar period in Europe, these new powers were put in the service of totalitarianism. In 1922, Joseph Stalin became general secretary of the Communist Party in the USSR and Benito Mussolini became the fascist prime minister of a coalition government in Italy. Six months earlier, Adolf Hitler had become the chairman of the National Socialist Party in Germany.

Fifteen years later, after the Nuremburg Laws and the opening of the first concentration camps, Edward Bernays was dismayed by the eyewitness report of a recent visitor to Berlin who told him that Joseph Goebbels was making intensive use of Bernays's book Propaganda in organizing Hitler's genocide.

In the U.S., also in 1922, Bernays's friend and former wartime propaganda colleague, Walter Lippmann, wrote: The manufacture of consent ... was supposed to have died out with the appearance of democracy. But it has not died out. It has, in fact, improved enormously in technique. As a result of psychological research, coupled with the modern means of communication, the practice of democracy has turned a corner. A revolution is taking place, infinitely more significant than any shifting of economic power.... The knowledge of how to create consent will alter every political calculation and modify every political premise.... It is no longer possible, for example, to believe in the original dogma of democracy.

As noted in the previous chapter, the combination of unlimited secret campaign contributions and extremely expensive but devastatingly effective psychology-based ma.s.s electronic marketing is indeed posing a deadly threat to the continued vibrancy and good health of partic.i.p.atory democracy. If the current a.s.sault on the integrity of democracy is allowed to continue, Lippmann's dark prophecy may yet come to pa.s.s; if elites can use money, power, and ma.s.s persuasion to control the policies of the United States, the average person may eventually come to a point where it seems, in Lippmann's words, "no longer reasonable" to believe that America is a democracy.

In the market sphere, the amount of money spent to "manufacture wants" and stimulate increased consumption has continued to rise year by year. The appeal of Freudian-based ma.s.s marketing began to wane later in the twentieth century, but more recently the invention of more sophisticated techniques such as brain scans has reinvigorated the use of subconscious a.n.a.lysis in the field of neuromarketing. Ma.s.s marketing to promote increased consumption is now so pervasive that we almost consider it to be a normal part of our environment. The average person living in a city used to see an average of 2,000 commercial messages per day thirty-five years ago. According to The New York Times, the average city dweller now sees 5,000 commercial messages per day.

WASTE AND POLLUTION.

Increased per capita consumption by a larger and larger global population is pressing against the limits of some resources. As both human population and the global economy grow in size, we are not only consuming more natural resources to make products, we are also producing larger and larger streams of waste. According to a recent report from the World Bank, the per capita production of garbage alone from urban residents in the world is now 2.6 pounds per person every day; and the total volume is projected to increase by 70 percent in a dozen years.

The cost of managing the garbage will almost double over the same period to $375 billion per year-with most of the increase in developing countries. According to the Organisation for Economic Co-operation and Development, each one percent increase in national income produces a .69 percent increase in munic.i.p.al solid waste in developed countries.

And that's just the garbage. When the waste a.s.sociated with energy production, the making of chemicals, manufacturing, electronic goods, agricultural waste, and waste from the paper products industries are apportioned on a per capita basis among the seven billion people who consume the results of all these processes, the actual amount of waste produced each day is more than the body weight of all seven billion people.

There is a thriving black market in the illegal disposal of waste-particularly shipments from developed countries to poor countries. In the European Union, exports of plastic waste-almost 90 percent of it to China-increased by more than 250 percent in the last decade. The news media has focused on the enormous "garbage patch" in the middle of the Pacific Ocean-made up mostly of plastic-but much larger volumes are on land in millions of waste dumps.

Although there have been some laudable efforts by many companies and cities to increase the recycling of waste, the total volumes are overwhelming the current capacity for responsible disposal practices. For example, organic waste can be used to produce valuable methane, but due to inertia and an absence of leadership, so much organic waste is simply dumped in unimproved landfills that it decomposes to produce 4 percent of all the global warming pollution each year.

The growing volumes of e-waste (waste a.s.sociated with electronic products) have been the focus of increasing attention because of the presence of highly toxic materials in the waste stream. And once again, even though recycling efforts are under way, the problem is still growing faster than the solution.

Toxic chemical and biological waste poses a particular challenge. During the 1970s and 1980s, I chaired and partic.i.p.ated in a large number of congressional hearings on the dangers of toxic chemical waste. The tough laws that were enacted in the wake of those and other hearings have since been severely weakened by chemical industry lobbying of the U.S. Congress and executive branch. A recent U.S. study by the Centers for Disease Control and Prevention identified traces of 212 chemical wastes in the average American, including pesticides, a.r.s.enic, cadmium, and flame r.e.t.a.r.dants.

Flame r.e.t.a.r.dants? Their presence in the tissues of Americans has an interesting backstory that provides another example of the imbalance of power in U.S. decision making and the dominance of corporate interests over the public interest. An exhaustive examination by the Chicago Tribune in 2012 demonstrated in detail how the cigarette industry corruptly influenced policymakers to legally compel the addition of toxic flame r.e.t.a.r.dants to the foam inside most furniture in order to save lives that were being lost in thousands of fires started each year by smokers who fall asleep and drop their lit cigarettes on a couch or chair.

A far more logical and less dangerous solution-one that had been proposed since the early part of the twentieth century-would have been to require the cigarette manufacturers to remove the chemicals they routinely add to cigarettes to keep them burning even when they are not being puffed. But the tobacco industry did not want to be blamed for the fires, and they worried that any inconvenience for smokers might hurt sales. So they came up with a corrupt scheme to buy enough influence to require the addition of dangerous chemicals to most all furniture instead.

When the companies manufacturing the flame r.e.t.a.r.dant chemicals began to understand how they benefited from this ruse, they joined in providing more money to support the tobacco companies' scheme. The same lobbyist represented state fire officials and the chemical manufacturers-and remained secretly on the payroll of the tobacco industry. Meanwhile, children continue to breathe in the dust from the decaying flame r.e.t.a.r.dants and scientists continue to link their exposure with evidence of cancer, reproductive disorders, and damage to fetuses. And, by the way, the Consumer Product Safety Commission recently found that the flame r.e.t.a.r.dants added to the foam in the furniture didn't work to cut down on house fires.

A few particularly dangerous chemicals, such as Bisphenol A (BPA) and phthalates (which are chemically similar to flame r.e.t.a.r.dants), have been singled out for special attention by health experts, but the law enacted in 1976 to deal with such chemicals, the Toxic Substances Control Act, has never been truly implemented. An estimated 83,000 chemicals are listed in the inventory of substances that should be tested, but the Environmental Protection Agency has required testing for only 200 of them, and has restricted usage of only 5. The chemical manufacturers are allowed to withhold most of the medically relevant information about these chemicals from regulators, by claiming they are trade secrets.

THE SURGE IN the development of agricultural and industrial chemicals following World War II was based in significant part on leftover stockpiles of unused nerve gas and munitions. (The inventor of poison gas in World War I was also the inventor of synthetic nitrogen fertilizer.) These new kinds of chemical compounds introduced more toxic forms of water pollution than in the past. In prior periods, water pollution had been dominated by fecal contamination causing typhoid and cholera. Although the latter problems have been largely solved in developed countries, waterborne diseases are still among the leading causes of death in developing countries, especially in South Asia, Africa, and portions of the Middle East.

Indeed, pollution of rivers, streams, and groundwater aquifers is a serious problem contributing to water shortages in many areas of the world. The World Commission on Water for the Twenty-First Century, in which multiple United Nations agencies partic.i.p.ate, reported in 1999 that "More than one-half of the world's major rivers are being seriously depleted and polluted." One of the reasons for this global tragedy is that neither depletion nor pollution is included in the world's prevailing system for measuring national income and productivity-GDP. As economist Herman Daly points out, "We do not subtract the cost of pollution as a bad, yet we add the value of pollution cleanup as a good. This is asymmetric accounting." As a result, decisions to clean up the environment are routinely-and inaccurately-described as hurtful to prosperity. For example, in Guangzhou, China, the vice director of the city's planning agency felt forced to defend a decision to limit automobile traffic as a means of reducing dangerous levels of air pollution by saying, "Of course from the government's point of view, we give up some growth, but to achieve better health for all citizens, it's worth it."

Recently, an investigation by The New York Times collected hundreds of thousands of state and federal records of water pollution under the Freedom of Information Act that showed that approximately one out of every ten Americans has been exposed to chemical waste or other health threats in their drinking water.

Since 1972, the United States has pioneered clean water protections and most of the developed world has followed suit. However, the progress in developing countries has fallen short of the 2000 Millennium Development Goals (a blueprint for global development agreed to by all 193 member states of the United Nations and 23 international organizations). According to the World Health Organization, "over 2 billion people gained access to improved water sources (defined as 'likely to provide safe water') and 1.8 billion people gained access to improved sanitation facilities between 1990 and 2010...[however] over 780 million people are still without access to improved sources of drinking water and 2.5 billion lack improved sanitation."

If current trends continue, these numbers will remain unacceptably high in 2015: according to the World Health Organization, "605 million people will be without an improved drinking water source and 2.4 billion people will lack access to improved sanitation facilities." In China, where 90 percent of the shallow groundwater contains pollution, including chemical and industrial waste, 190 million Chinese become ill each year due to their drinking water, and tens of thousands die.

Supplies of freshwater are unevenly distributed, with more than half of the total located in only six countries. The declining availability and deteriorating quality of freshwater in numerous countries and regions stands alongside the loss of topsoil as one of the two most serious limitations constraining the expansion of food production. Overconsumption and profligate waste of freshwater-new compet.i.tion for water from cities and the growing demands of Earth Inc.-are threatening to create food crises in multiple areas of the world.

Just as urban sprawl has had an impact on the supply of agricultural land, "energy sprawl" is also having a harsh impact on the availability of freshwater for food crops. The unwise decision to promote the rapid growth of first generation ethanol fuels and biodiesel from palm oil has reallocated both water and land resources from food crops. And the growing craze for deep shale gas, which requires five million gallons of water per well, has put severe strain on supplies in regions that were already experiencing shortages. Many cities and counties in Texas, for example, have now been forced to choose between allocating water to agriculture and hydraulic fracturing (fracking) of gas and oil. On a global basis, the use of water for energy production is projected to grow twice as fast as energy demand.

The expansion of oil and gas fracking is adding to the injection of toxic liquid waste into areas deep underground that have been thought to be safe repositories-until recently. In the United States, an estimated 30 trillion gallons of toxic liquid waste have been injected into more than 680,000 wells for underground storage over the past few decades, even as the practice of fracking changes the underground geology, opening new fissures and modifying underground flow patterns. Unfortunately, some of these deep repositories have leaked waste upward into regions containing drinking water aquifers.

Groundwater resources represent approximately 30 percent of all the freshwater resources in the world, compared to one percent represented by all of the surface freshwater. In the last half century, the rate of shrinkage in groundwater aquifers has doubled. The rate at which groundwater withdrawals have been increasing has accelerated steadily over the last half century to double the rate in 1960, but in the last fifteen years (since the growth rates of China and other emerging economies have accelerated), the increases have proceeded at a much faster pace.

The introduction of new water drilling and pumping technology has also been a significant factor. In India, for example, $12 billion has been invested in new wells and pumps; more than 21 million wells have been drilled by the 100 million Indian farmers. Partly as a result, the aquifers in many communities have been completely dried up and drinking water has to be trucked in-while farmers must rely on increasingly unpredictable rainfall.

Because of the growth in population and the increase in water consumption, the surface water from many of the world's important rivers is now so overallocated that many of the rivers no longer reach the sea: the Colorado, the Indus, the Nile, the Rio Grande, the Murray-Darling in Australia, the Yangtze and Yellow rivers in China, and the Elbe in Germany.

A SWELLING POPULATION.

Although population growth rates have slowed in most of the world over the past several decades, the overall size of the population is now so large that even a slower rate of growth will add billions more people before our numbers stabilize near the end of this century at a total that is now difficult to predict but is estimated at between 10 and 15 billion. (There is also a low projection of 6.1 billion people, and a runaway projection of 27 billion people-that would occur if there are no further decreases in fertility. But the vast majority of experts a.s.sume that the most likely range is slightly above 10 billion.) In the next dozen years, India will surpa.s.s China for at least the balance of the century as the most populous nation on Earth. In the next two dozen years, Africa will have more people than either China or India and by the end of the century is projected to have more people than both combined. Half of the global growth in population over the next four decades is projected to take place in Africa, which is now on track to more than triple its present population, to an astonishing 3.6 billion, by the end of this century. Given the dangerously low levels of soil fertility in much of Sub-Saharan Africa, shortages of freshwater, poor governance in many countries, and the projected impact of global warming, the limits to growth in Africa are likely to be a central focus of the world's attention in the balance of the twenty-first century.

The reason it is so difficult to predict peak global population, and the reason that the range of estimates varies by five billion people-as many as all the people in the world at the end of the 1980s!-is that it is inherently difficult to predict how many children the average woman will prefer to have during the next several decades. An increase in that key variable by even a half a child (demographers have long since become numb to the discomfiture of that expression) can mean the difference in several billion people in world population in the course of the next eighty-seven years. The multiple factors that have an impact on women's preferences are, in turn, also difficult to project over such a long period of time.

These new higher projections for peak global population in the latter part of the twenty-first century reflect a slower than expected decline in the average fertility rate in scores of less developed countries-the majority of them in Africa. The biggest single reason for the increased population estimates for Africa and the world is the failure of the world community to make fertility management knowledge and technology available to women who wish to use it.

Population and development specialists have learned a great deal over the last few decades about the many factors that actually drive changes in the dynamics of population growth. Voluminous research has shown conclusively that four elements of the population puzzle all fit together and act in combination to shift the pattern of population growth in any country from one equilibrium-characterized by high death rates, high birth rates, and large families-to a second equilibrium-characterized by low death rates, low birth rates, and small families.

The good news is that the global effort to slow population growth is actually a success story, albeit one that is unfolding in slow motion. Even though very large increases in our absolute numbers will continue for many decades to come, almost every nation in the world has been moving from the high equilibrium state toward the low equilibrium state. Some have changed quickly but others are lagging behind. In the U.S., the rate of growth in population has slowed to the lowest level since the Great Depression.

For several decades in the twentieth century, the prevailing view was that increases in GDP-particularly those factors a.s.sociated with industrial development-were the key to falling population growth rates. This was another early ill.u.s.tration of the seductive convenience and illusory simplicity of GDP as a proxy measurement of generalized progress and how it can capture the attention of policymakers, even when it is only loosely connected to the real goals they are trying to reach.

Although GDP is not one of the four factors, economic growth is loosely correlated in many countries with the creation of social conditions that can and do have an impact on population. And conversely, in most instances, extreme poverty is certainly correlated with higher population growth rates-especially in countries with failing inst.i.tutions and shortages of clean water and topsoil. All fourteen nations with those three characteristics have extremely high population growth rates; thirteen of the fourteen are in Sub-Saharan Africa.

The four relevant factors, all of which are necessary but none of which, by itself, is sufficient, are: * First, the education of girls-the single most powerful factor. The education of boys is also important, but population statistics show clearly that the ability of girls to become literate and to obtain a good education is crucial.

* Second, the empowerment of women in society, to the point where their opinions are heard and respected, and they have the ability to partic.i.p.ate in making decisions with their husbands or partners about family size and other issues important to their families.

* Third, the ubiquitous availability of fertility management knowledge and technology, so that women can effectively choose how many children they wish to have and the s.p.a.cing of their children.

* Fourth, low infant mortality rates. As an African leader, Julius K. Nyerere, said midway through the twentieth century, "the most powerful contraceptive is the confidence by parents that their children will live."

The struggle to provide access to contraception and the knowledge of how to manage fertility has not gone as well as social scientists and population experts had hoped. The commitments by wealthy countries to finance wider access in poor countries to fertility management have not been fully met. In some developed countries where democracy is being weakened, like the United States, attacks on programs beneficial to women have been more successful in recent years. Political opposition to contraception, for example, has surprisingly reemerged in the United States in the last two years, even though the overwhelming majority of American women (including 98 percent of s.e.xually active Catholic women) support it and even though it seemed to be a question that had been settled in the 1960s.

The religion-based opposition to contraception by a tiny minority in the U.S. has also had a harsh impact on U.S. contributions to the global effort to make fertility management available in fast growing developing countries-in part because of the disingenuous conflation of contraception and abortion. Since foreign aid is always vulnerable to budget cuts in the United States, the amount of help actually provided has fallen far short of the amount pledged. And once again, the imbalance of power and political paralysis in the U.S. has deprived the world of desperately needed leadership, which, in turn, has seriously damaged the world's ability to take action.

Partially as a result, antic.i.p.ated declines in fertility rates have not been achieved-especially in Africa, where thirty-nine out of the fifty-five African countries have high levels of fertility. (There are nine high-fertility countries in Asia, six in Pacific Island nations, and four in the low-income countries of Latin America.) In thirty-four of the fifty-eight high-fertility countries in the world, population will triple in the balance of this century.

On a global basis, women now have an average of 2.5 children during their childbearing years. In Africa, however, the average is almost 4.5 children per woman. Moreover, in four African countries, the average woman is still expected to have more than six children, leading to disruptive and unsustainable population growth. Malawi, for example, which has 15 million people today, is projected to have a nearly tenfold increase in population by the end of the century to an estimated 129 million. The African nation with the largest population, Nigeria, is projected to increase from slightly more than 160 million people today to more than 730 million by 2100. That would put Nigeria's population at the level of China in the mid-1960s.

Before the improved understanding of population dynamics, many people a.s.sumed that higher death rates reduce overall population. But the impact of high death rates on high birth rates gives the lie to this former belief. The Black Death of the fourteenth century did reduce population-indeed, that is believed to be the last time population has declined. But in today's world, even the most feared diseases have not had an impact on population. The HIV/AIDS epidemic has had an impact on the overall numbers of people in a few African countries, but on a worldwide basis population grew by more in the first five months of 2011 than all of the deaths from HIV/AIDS since the disease first began rapidly spreading three decades ago.

In countries with high rates of infant mortality, the natural tendency of parents is to have more children in order to ensure that at least some of them will survive to take care of their parents in old age and to carry on the family name and tradition. In practice, when child death rates fall dramatically, birth rates generally decline a half generation later-provided the other three factors are also present. Following World War II, revolutionary advances in health care-higher levels of sanitation, better nutrition, antibiotics, vaccines, and other achievements of modern medicine-led to significant declines in child and infant mortality in many countries around the world. This same combination of improvements in health care and nutrition has doubled life expectancy in industrial countries from the beginning of the nineteenth century-from thirty-five to seventy-seven years.

AN AGENDA FOR WOMEN AND GIRLS.

The education of girls has become commonplace around the world, including in most countries that used to focus only on the education of boys. Although there is still opposition to the education of girls among groups such as Afghanistan's Taliban, most nations have long since become aware of the compet.i.tive advantages, especially in the information age, of educating all their children. Saudi Arabia used to focus on boys alone in their school systems, but according to the most recent statistics available, almost 60 percent-compared to 8 percent in 1970-of college students in Saudi Arabia were women.

The comparable figure in Qatar is 64 percent, in Tunisia and the United Arab Emirates, 60 percent; the average in Arab states is now 48 percent; in Iran 51 percent. Indeed, more women than men received college degrees in 67 of the 120 nations for which statistics are available. The world average is 51 percent. In the United States, women now receive 62 percent of a.s.sociate's degrees, 58 percent of bachelor's degrees, 61 percent of master's degrees, and 51 percent of doctoral degrees.

The empowerment of women, on the other hand, remains a challenging goal in many traditionalist societies. None of those women college graduates in Saudi Arabia, for example, is allowed to drive a car-or vote-although their relatively progressive king has announced plans to allow women to vote beginning in 2015. Even though 93 percent of the gender gap in education of women has been closed on a global basis, less than 60 percent of the gap in economic partic.i.p.ation and only 18 percent of the gap in political partic.i.p.ation have been closed.

The Global Mind has accelerated demands for the empowerment of women throughout the world; women make up more than half of all social network users globally, and almost half of all Internet users. When they are exposed to the more favorable norms of gender equity in advanced countries, they naturally become impatient for change.

Women have been coming into the workplace in almost all countries in higher numbers than men, reflecting a historic change in global att.i.tudes about women working outside the home. In fact, for the last forty years, two women have entered the workplace for every man. Women have made a particular difference in the compet.i.tiveness of rapidly growing East Asian nations, with 83 women in the workforce for every 100 men. They have had the biggest impact in several export-oriented businesses, including clothing and textiles-filling between 60 to 80 percent of the jobs.

The Economist has calculated that on a global basis, "the increased employment of women in developed economies has contributed much more to global growth than China has." In developed countries as a group, women are responsible for producing slightly less than 40 percent of GDP. However, another flaw in the way GDP is measured-one noted by Kuznets when he first introduced it in 1937-is that it does not a.s.sign any economic value to the work women (and some men) do in the home: raising children, cooking meals, keeping the household, and all the rest. If this housework in developed countries were valued at the amount that would be paid for nannies, cooks, and housekeepers, the total contribution of women to GDP would be well over 50 percent.

The movement of women into jobs outside the home has had startling social impacts. In the United States, during the three decades between the 1960s and 1990s, the percentage of married women with children younger than six years old who work outside the home skyrocketed from 12 percent to 55 percent. The percentage of all mothers with young children who chose to work outside the home rose during the same three decades from 20 to 60 percent.

These sociological changes are also among the many factors contributing to the obesity epidemic. Because many more mothers are now working outside the home, and a much higher percentage of children live in families where both parents work, more people eat fast food, other restaurant food, and manufactured meals and food products designed for minimal preparation, such as microwaving. Portion sizes have also increased along with the body ma.s.s index. It all adds up to what Kessler calls "conditioned hyper-eating."

Studies also show that children in low-income neighborhoods are often permitted and even encouraged by their parents and caregivers to watch more television than average because of greater concerns about their safety playing outside in neighborhoods that, relatively speaking, are p.r.o.ne to more violence. This mirrors a global trend for people of all ages, who are spending more time on electronic screens connecting to the Global Mind and are, on average, more likely to work in jobs that do not require as much physical activity as in the past. The trend toward more driving and less walking is also a factor.

THE CHANGING FAMILY.

The increased partic.i.p.ation of women in the workforce, the dramatic changes in the education of women, and changes in social values have also led to significant structural changes in the inst.i.tution of the family. Divorces have increased dramatically in almost every part of the world, partly due to new legislation making them easier to obtain, and, according to experts, partly because of the increased partic.i.p.ation of women in the workforce. Some experts also note the role of online relationships; according to several a.n.a.lyses, between 20 and 30 percent of all divorces in the U.S. now involve Facebook.

The age at which the average woman gets married has also increased significantly, and a larger percentage of men and women choose never to marry at all. Fifty years ago, two thirds of all Americans in their twenties were married. Now, only one quarter are. Many more couples are living together-and having children-without getting married. Forty-one percent of children in the U.S. are now born to unmarried women. Fifty years ago, only 5 percent of U.S. children were born to unmarried mothers. Today, the comparable figure among mothers under thirty is 50 percent. Among African American mothers of all ages, the percentage is now 73 percent.

In the overall rankings of countries on the basis of gender equity, the four highest are Iceland, Norway, Finland, and Sweden; the lowest rank goes to Yemen. However, the political partic.i.p.ation of women has lagged far behind most other indicators of gender equity. On a global basis, women make up less than 20 percent of elected parliaments, with the highest percentage (42 percent) in the Nordic countries and the lowest percentage (11.4 percent) in the Arab states. The United States is barely above the global average. Only two countries in the world have a female majority in their parliaments-one of the tiniest countries, Andorra, and one of the poorest, Rwanda, which in the wake of its 1994 tragedy enacted a const.i.tutional requirement that a minimum of 30 percent of its parliament be women. The empowerment of women in corporate governance is lower still-with only 7 percent of corporate boards in the world made up of women.

All four of the factors that bring about a reduction in population growth rates are connected to the expansion of partic.i.p.atory democracy and the right of women to vote. In those countries where women vote in high percentages, there is understandably more support for programs that reduce child mortality, educate girls, further empower women, and ensure high levels of access to fertility management.

In most wealthy industrial countries, birth rates have fallen so swiftly that some now have declining populations. Russia, Germany, Italy, Austria, Poland, and several other countries in Eastern and Southern Europe now have fertility rates well below the replacement rate. j.a.pan, South Korea, China, and several countries in Southeast Asia have also fallen below the replacement rate. The U.S. birthrate fell to an all-time low in 2011.

In a few of these countries, the fertility rate has fallen so low that they are in danger of falling into what demographers call the fertility trap. That is, fewer women of childbearing age will themselves have fewer children, adding up to a sudden and sharp further decline in population. j.a.pan's population is projected to decline from 127 million today to 100 million by midcentury, and 64 million by 2100.

Sweden and France both adopted policies some years ago to increase fertility and avoid the fertility trap; both countries spend roughly 4 percent of their national income on programs that support families and make it easier for working parents to have children if they wish: generous maternity and paternity leave, free preschool, affordable high-quality child care, excellent child and maternal health care, protections for women returning to their career paths after having children, and other benefits. Both countries are now once again nearly at their replacement rate of fertility.

By contrast, j.a.pan and Italy have failed to provide such services and have not yet been able to slow their fertility declines. As a result, they will soon face great difficulty in financing pensions because of a dramatic change in the ratio of their working-age population to their retired population. Social contracts that are based on financing mechanisms that tax work to pay for retirement are far more burdensome for working people when there are many fewer of working age compared to the number who are retired.

LONGEVITY.

To a greater or lesser degree, this new demographic reality is a major cause of the budget crises in most developed countries in the world today. Similarly, since health care is used more intensively by older people, the same demographic changes have contributed to developed country budget crises for health care programs-most of all in the United States, because of the greater per capita expense of U.S. health care compared to any other nation.

The relative size of the retiree population is also increasing because of a significant increase in average lifespans almost everywhere. Incredibly, more than half of the babies born in developed countries after the year 2000 are projected to live past the age of 100. In the United States, more than half of the babies born in 2007 will live to be more than 104.

This revolution in human longevity is causing dramatic adjustments throughout the world. Although statistics are hard to come by, anthropologists believe that the average human lifespan for most of the last 200,000 years was probably less than thirty years; some believe much less. After the Agricultural Revolution and the building of cities, lifespans began climbing slowly upward, but not until the middle of the nineteenth century did the average lifespan reach forty. In the last 150 years, however, average lifespans worldwide have climbed to sixty-nine-and in most industrial countries are now in the high seventies.

Improvements in sanitation, nutrition, and health care-particularly the introduction of antibiotics, vaccines, and other modern medicines-have played the most important roles in increasing lifespans. But education levels, literacy, and the distribution of information about health care have also had major impacts. Access to information online about health and wellness has also begun to play an even more significant role. Globalization and urbanization have magnified these factors in some countries, leading to even more rapid increases in longevity. China is projected to double the percentage of its population represented by those aged sixty-five and older within the next quarter century.

The larger ratio of older people in some countries represents only one ill.u.s.tration of how changes in societies can be driven not only by the absolute size of populations but also by changes in the distribution in different age groups. When a baby boom generation comes into the workforce, societies with an ample number of jobs to be filled can experience enormous productivity gains. Yet years later, when that same generation ages, they are sometimes less able to adapt quickly to new technology and new demands for flexibility in the workforce, as in the age of Earth Inc. If a subsequent decline in fertility leads to smaller successive generations entering the workforce to replace them, the same cohort that clamored for revolutionary change in their youth start clamoring for bigger pension checks and better health care in their old age.

China enjoyed an economic boom for the last three decades, powered by a young workforce. Yet, within the next two years, China's working age population will begin to decline, and by 2050 fully one third of Chinese will be sixty or older. Similarly, the percentage of the Indian population over sixty-five will double during the same thirty-seven years, though the percentage of the elderly will still be half that in China.