by David Orrell
Along with agriculture, massive macro-engineering projects began to leave their mark. During the Qin and Han dynasties (221 B.C. to 220 A.D.), large parts of China’s forests were cut down to provide scaffolding, fuel, and housing for wooden cities and the Great Wall. The wood required during the building of the Great Pyramid of Khufu, in Egypt, came from cedar trees in Lebanon. Deforestation in many areas affected the local climate and led to permanently warmer and drier conditions—the Fertile Crescent is no longer so fertile.
The increasing size and density of cities led to rapid transmission of ideas and the development of sophisticated culture. Bigger cities also created the conditions to support and sustain epidemics. Rome in the third century A.D. had a population density similar to that of a tenement in today’s Mexico City, and there was no running water or sanitation. Deadly outbreaks were frequent occurrences. The Plague of Justinian (540–42), believed to have been bubonic plague, is estimated to have killed 25 to 40 percent of Europeans. A thousand years later, the disease returned as the Black Death, with a similar effect on population. The impact of these pandemics was so large that according to one theory, it can even be measured in carbon-dioxide emissions.12 Antarctic ice cores store air samples absorbed from the atmosphere over millennia, providing a record of atmospheric carbon dioxide; during plague years, farms were allowed to grow wild, so they absorbed carbon dioxide from the air, producing a dip in the records. Only smallpox would prove more deadly.
We didn’t get the upper hand over disease until the invention, by James Watt and others, of that great cure-all, the steam engine. This kick-started the Industrial Revolution in England by making it possible to transform coal into energy. Improved economic and material conditions, along with developments in sanitation and medical techniques such as vaccination, soon resulted in significantly lower death rates. The world population expanded, reaching the billion mark in the first half of the nineteenth century. By 1930, we were up to 2 billion souls, some with their own cars, now powered by that other carbon source. Birth rates slowed in industrialized countries, but elsewhere they remained high. Population grew in a roughly exponential fashion, and this growth was supported by the Green Revolution of the 1970s, which led to more productive agriculture and increased the planet’s capacity to feed the species. At the millennium, the world headcount had reached a frothy 6.1 billion. About 10 percent of the people who have ever lived are alive today. The earth has never before supported humanity on such a scale.
Economies also grew at a rapid clip. At the time of Christ, per capita income would equate to about a dollar per day (around what a person in an impoverished country can survive on today). Since then, it has increased, on average, to about fifteen dollars, with much of this increase occurring after 1700.13 Like successful suburbanites, we have grown both larger and richer. But how is the planet doing? What would Plato or his mentor, Socrates, say now?
THE WORLD: OVER 6 BILLION CUSTOMERS SERVED
As our population and economic processes have expanded, our impact on the environment has grown. Large areas of “new” countries like Brazil and Canada are fairly pristine, but in many areas of the planet, “only the bare framework of the land [is] left.” About a quarter of all ice-free land has been transformed into cropland or pasture, and much of the rest is exploited in some way for natural resources.14 Around half the world’s forests are now gone, and more have been significantly fragmented or otherwise degraded. Engineering works and other processes disrupt the earth’s surface on a scale comparable to that of erosion by wind or water. All life forms transform their local environments, but our impact is multiplied by technology. Other species don’t cover the land in concrete.
Our impact on the oceans is less immediately visible, since it is under water and out of sight. However, populations of large fishes such as tuna and cod have crashed by as much as 90 percent. Techniques like bottom trawling have laid waste to fragileocean-floor ecosystems and all but depleted fishing grounds like the Georges Bank off Nova Scotia.15 The water quality in some areas has recently improved—the Thames River, for example, is cleaner than it has been in decades—but those lakes, rivers, and streams that do not supply the wealthy with drinking water or recreation are often highly polluted. Changing rainfall patterns, combined with inadequate drainage, has led to increased flooding worldwide.16
In the air, fossil-fuel emissions have caused a rapid rise in atmospheric carbon dioxide. The Antarctic ice records show that the carbon dioxide level has stayed within a band of about 180 to 280 parts per million for the past few hundred thousand years—until recently. In 1958, it reached 315 ppm, and it is now about 380 ppm, and climbing.17 Much comes, almost invisibly, from the exhaust of private vehicles; every fifty litres of gasoline contributes about 115 kilograms of the gas. Local air pollution is of course not a new phenomenon—people complained about the soot in ancient Rome. However, pollution is now a global problem, and chemically synthesized molecules, with their complex and often unknown effects on atmospheric and biological chemistry, are ubiquitous.
The waste products of civilization also affect local and global climates. Carbon dioxide is a greenhouse gas and contributes to global warming. Over the course of the twentieth century, the planet’s average surface temperature rose by about 0.6°C. The 1990s were the warmest decade since record-keeping began, and the 2000s are so far following suit. Among other effects, this has led to increased forest fires across the world. Even the (normally damp) Amazon rainforest in Brazil and Venezuela is now vulnerable (as shown when a portion the size of Belgium was destroyed by fire in 1997–98).18
Human actions have therefore profoundly affected land, water, air, and fire. The only one of Plato’s elements not to have been touched is the ether—unless we count the electronic signals beamed around the world by satellite. And we have an even greater impact on life. While we as a species are doing well, our effect on creatures of the land, oceans, and skies has often been disastrous. We prosper as other species crash.19 Every extinction knocks another set of genes out of the world gene pool and affects the robustness of the global ecosystem.
Even this low-resolution history of the world is enough to show that we are living in unusual times: what we take as normal isn’t that normal. The climate is always prone to change, but over the past 10,000 years, humanity has enjoyed a warm and relatively stable period that has been suitable for the development of agriculture. We seized that window of opportunity, and now we have put almost all suitable land to the purpose of feeding ourselves. The length and quality of life in many countries has as a result increased enormously, but at the expense of degrading the existing air, water, and soil. And while our stone-age ancestors could react to land loss or shifting climates by moving, we don’t have that flexibility; there’s little slack in the system. As people in poor nations cluster in vulnerable areas, they are increasingly susceptible to natural disasters, such as the storm that hit Venezuela in 1999.
Many people in industrialized countries have grown up with a greatly reduced fear of infectious disease. Antibiotics and improved sanitation were a great success story of modern science, and they have vastly reduced death rates in many countries. The last really serious influenza pandemic to hit the rich world, in 1918, killed at least 20 million and made many more ill. Bubonic plague has been all but eradicated; smallpox exists only in the lab.20 Of course, the gains won were not permanent or global. The number of people infected with HIV/AIDS worldwide is about 40 million. New diseases such as SARS continue to emerge, and overuse of antibiotics has led to resistant strains of old diseases like tuberculosis.
Perhaps the most unusual thing about recent history, though, has been the extraordinary rate of economic growth. Industrialized countries like the United States commonly try to achieve annual growth rates in gross domestic product of around 3 or 4 percent. If the homme moyen had pulled in a dollar per day 2,000 years ago and a growth rate of only 1 percent over inflation was maintained since, he would today be enjoyin
g a healthy pay packet of $439 million per day.21 Since not everyone plays NBA basketball, this is clearly impossible. Economic growth is the relatively recent by-product of the Industrial Revolution. In rich countries, we have until now had the best of all possible worlds: a good climate, excellent health, and an explosive economy. In bread-making terms, we are like a yeast colony in a dough: carefully nourished with all the requirements for life, covered with a towel, left undisturbed in a warm place, and growing exponentially. So how long can this go on?
LIVING IN A BUBBLE
According to chart-following optimists, the answer is forever. After all, many worriers have cried wolf in the past, and their dire predictions never came true. Malthus thought the world would disintegrate into famine, plagues, and wars, but while these have certainly happened, none has come close to stopping the growth of the total world population. We have the wind in our sails, momentum behind us, and nothing can hold us back. Global warming and overpopulation are just the fevered inventions of a neurotic society that is living in the safest period of human history and is egotistical enough to believe its challenges are unique.22
One such optimist is Michael Crichton, the author of thrillers such as Jurassic Park and the creator of the hit television hospital drama “E.R.” For his 2004 thriller, State of Fear, he spent three years researching climate change and the environment, and he came in on the side of the skeptics. In an appendix to that novel, which created a lot of controversy and was cited in the U.S. Senate as a useful contribution to the global-warming debate, he argued that climate predictions are hopelessly unreliable, and that improved technologies will mean that we never run short of resources. “For anyone to believe in impending resource scarcity, after 200 years of false alarms, is kind of weird,” he wrote. “I don’t know whether such a belief today is best ascribed to ignorance of history, sclerotic dogmatism, unhealthy love of Malthus, or simple pigheadedness.”23
Indeed, we have been told many times that we are on the verge of running out of oil or water or some other resource. The United States Bureau of Mines predicted in 1914 that American oil would run dry within ten years. Similarly alarmist predictions were made by the Department of the Interior in 1939 and 1951 (thirteen years of U.S. oil left), and by the Club of Rome in 1972 (not much of anything left). All, apparently, were proved wrong. As Adam Smith knew, scarcity means that the price goes up, so either new sources are found, which is what happened with oil (the Alberta tar sands are big), or an alternative is developed.24 In their book The Bottomless Well, Peter Huber and Mark Mills argue that energy use is positively virtuous, because “energy begets more energy. . . . The more energy we seize and use, the more adept we become at finding and seizing more.”25 According to this theory, when we approach a stop sign, we should step a little harder on the gas.
Some scientists have always believed that science itself will learn to control the progress of the human race and steer us to safety. In A Masculine Birth of Time, Sir Francis Bacon wrote of science bringing about “a blessed race of Heroes and Supermen.” As the psychologist B. F. Skinner wrote in 1973, “What we need is a technology of behaviour. We could solve our problems quickly enough if we could adjust the growth of the world’s population as precisely as we adjust the course of a spaceship.”26 And if that doesn’t work, and we run out of room, we could always try a real spaceship and find another planet to colonize.
Optimism in the power of science and progress is heartwarming, but those pigheaded people who believe in fundamental analysis tend to take a more jaundiced, seasoned view. They will point out that recent successes took place in a very favourable environment, which may not continue; that these successes have been mostly limited to rich countries and have done little for a substantial proportion of the population; that excessive expansion often results in overshoot of fundamental limits (i.e., a bubble); and that when bubbles burst, they do so with a bang. In other words, all the boosterism for human ingenuity and technology is about as meaningful as that heard for the latest tech firm at the turn of the millennium.
These fundamental analysts will cast a questioning eye over S-shaped curves such as that shown in figure 7.1 (see page 282). Most current prognosticators have the world population shrinking slightly in rich countries and growing progressively more slowly in developing countries, until it gently coasts to an equilibrium around 2150. This is based on the observation that as developing countries get richer, the death rate decreases and population goes up. After a while, the birth rate also decreases (rich people have fewer children, for some reason), so growth slows or levels out.
Because the time scale for human reproduction is slow, population projections can be relatively accurate thirty or so years in advance—but only if nothing unusual happens (such as the baby boom, which forecasters failed to predict).27 Like economic models, demographic models tend to extrapolate the past and do not capture major turning points, like the one that is supposedly coming up. A fundamental analyst will therefore ask if this estimate of future growth, based on current trends, can be reconciled with the actual number of people the earth can support over the long term (its carrying capacity). If not, then we are living in a bubble. Rather than taper off at a sustainable limit, the population will overshoot and then crash—as has happened time and again on a more local scale with previous civilizations.28
FIGURE 7.1. Total estimated world population.29
The carrying capacity depends on, for example, whether everyone will be living at current First World standards. Its calculation implicitly assumes all kinds of things about economic and technological growth and the resilience of nature. (Even the definition of “sustainable” is nebulous. I will take it to refer, like homeostasis, to maintaining a kind of dynamic metabolic balance with the environment. Sometimes it is easier to define in the negative—Easter Island, not sustainable.) For everyone to enjoy a Western lifestyle, one estimate pegs the carrying capacity at around the 1930 population of 2 billion.30 This might seem low, but it accounts for the fact that rich people have far more impact on the planet than poor people. The environmentalist World Wildlife Fund estimates that by 2050, we will need almost three earths to support ourselves in the style to which we have become accustomed.31 Others believe that new technologies will allow us to support a much greater density, even higher than today’s. What is evident is that we are currently degrading the biological and physical systems that support life. In the words of the United Nations’ 2005 Millennium Ecosystem Assessment, we are “living beyond our means.”32
There is a chance that our technology will improve and growth rates will slow and reverse, steering the population back to a sustainable level; but there is also the possibility of a dramatic collapse. Maybe the Club of Rome was right. If so, then environmental skeptics are not skeptics at all—they are boosters who make naïve extrapolations based on recent performance. The true skeptics are people like Sir Martin Rees, Astronomer Royal, who pegs our civilization’s chances of survival to the end of the century at only 50 percent.33 (His predecessor in that position, John Dee, was also interested in predictions of the apocalypse, but his were based on the whispering of angels.34)
One study on opinions about climate change revealed a striking cultural divide between natural and social scientists.35 The latter, which includes conventional economists, tend to believe that the impact of even severe global warming will be low, and that we can invent replacements for “climatic services.” The former, which includes climate scientists, are far more pessimistic, and estimate the economic damage of global warming to be twenty to thirty times greater, with much of it assigned to non-market categories like nature or quality of life. Perhaps economists have more at stake in the existing economy.
So if we can’t even agree on the scale of the problem, what can computer models tell us about the future? Is it possible to make accurate predictions for the planet, or will the question be bounced back and forth between optimists and pessimists until time tells us the answer? And what
can we say about the implications for our weather, health, and wealth?
WEATHER: GETTING WARM
While our impact on the planet is combinatorial, one issue that has received much recent attention and controversy is climate change caused by the accumulation of greenhouse gases in the atmosphere. We still fear the weather gods, and the more extreme possibilities— all-destroying hurricanes, killer droughts, apocalyptic floods—evoke images of almost biblical wrath. Sudden changes in climate have always been a risk—a thought here for the pre-Inca Moche of the Andes, or the Maya of Central America, whose water supplies were cut off by shifts in weather patterns—but we may become the first civilization to be affected by our own actions on a global scale. The scientist and environmentalist David Suzuki said, “Climate change is one of the greatest challenges humanity will face this century.”36 Meteorologists, meanwhile, see global warming as a tractable and interesting theoretical problem that can be addressed by the use of large mathematical models. But is it possible to predict the climate if we can’t predict next week’s weather?
The basic physics behind global warming was pointed out by the Swedish chemist Svante Arrhenius in 1896.37 The earth is warmed by energy from the sun, which arrives as a broad spectrum of electromagnetic radiation, including visible sunlight. Bodies at the earth’s temperature in turn emit long-wavelength, infrared radiation (which is how soldiers can detect people in the dark using night-vision goggles). Instead of radiating out into space, this energy is mostly absorbed by the atmosphere. The degree of absorption depends strongly on the exact concentrations of certain gases. These are known as greenhouse gases because they have the same effect as the glass in a greenhouse does: they let the light in, but don’t let the heat out. This is not a subtle effect. Without greenhouse gases in the atmosphere, the average temperature would be –18°C instead of +14°C. We have all been raised in a hothouse.
