The greatest shortcoming of the human race
is our inability to understand the exponential function.
— ALBERT ALLEN BARTLETT
Sooner or later, anything that physically grows must stop. This is true of plants, animals, and colonies of bacteria. It’s equally true of civilizations. And if the rate of growth is exponential, the end can come with surprising rapidity.
In this chapter, we’ll discuss how we misperceive exponential growth, and how human growth is finally bumping up against the hard physical limits of our biosphere. One way or another, and sooner or later, these limits will drive a radical transformation of human civilization.
Many people assume that the human population can grow exponentially forever because we’ll soon populate planets orbiting other stars, or that our economy can grow exponentially forever by decoupling from physical resources. Not only are these techno-dreams unrealistic,1 they’re dangerous distractions. Instead, I hold a different dream: living well on Earth without growth.
Every day, something growing linearly adds a fixed amount, but something growing exponentially multiplies by a fixed amount. I’ve noticed that my brain extrapolates growth by assuming trends will follow a straight line over time. For most processes, this is a good short-term approximation. But if this is true of most human brains, and I think it is, it explains why exponential growth takes us by surprise: it sneaks up on us by seeming linear at first. Then it explodes.
Here’s a story illustrating this explosiveness.2 Ernst Stavro Blofeld has handcuffed James Bond to a seat in the top row in the Rungrado May Day Stadium3 in North Korea, the largest stadium in the world. Blofeld informs Mr. Bond that workers from SPECTRE have waterproofed the stadium and have placed a machine on the center of the field, far below, that releases one drop of water4 after the first minute, two drops after the second minute, four drops after the third minute, and continues doubling the number of drops each minute. He then says, “Goodbye, Mr. Bond,” and leaves. Bond has discerned the make and model of his handcuffs from the sound they’d made when closed; from his extensive practice, he knows it will take him exactly 52 minutes to escape.
Bond feels confident as he works. After all, he can’t see any water on the field, and it’s just a few drops each minute. This is too easy, he thinks. Blofeld has finally lost it. After 25 minutes, Bond can barely make out a glimmer far down on the field that might or might not be a puddle. Bond thinks nothing of it and concentrates on the task at hand. When he looks up again 19 minutes later, however, he’s shocked to see that the field is covered by water to a depth of 14 meters, and the surface is rising visibly. Bond barely has time to take his final preparatory breaths for extended immersion, because two minutes later he’s under water.5
This story is an allegory for global warming or any one of a number of interconnected exponential processes to be explored in this chapter. Human greenhouse gas emissions (mainly CO2) and atmospheric CO2 concentration are both growing exponentially at a rate of 2.2% per year (see Chapter 3). Something growing at a continuous rate of R percent per year doubles every 69/R years.6 At 2.2% annual growth, the cumulative amount of greenhouse gases we’ve dumped into the atmosphere is doubling every 30 years.7
Before James Watt patented his steam engine in 1781, the atmosphere’s CO2 concentration was 280 ppm. The Earth’s climate was stable and amenable for human civilization. By 2014, the CO2 concentration had risen to 400 ppm. This increase implies that if we continue business as usual, 30 years after 2014 the human contribution of 120 ppm will have doubled, taking us up to 520 ppm in 2044. If we exceed emissions growth of 2.2% per year, we will of course reach this doubling a little sooner; if we ramp down from 2.2% per year, it will take longer.
TABLE 5.1. CO2 concentrations at 2.2% annual growth.
Year |
ppm CO2 |
% of 280 ppm |
1793 |
280.9 |
0% |
1825 |
281.9 |
1% |
1856 |
283.8 |
1% |
1888 |
287.5 |
3% |
1919 |
295 |
5% |
1951 |
310 |
11% |
1982 |
340 |
21% |
2014 |
400 |
43% |
2046 |
520 |
86% |
2077 |
760 |
170% |
2109 |
1240 |
340% |
2140 |
2200 |
690% |
Table 5.1 shows CO2 concentrations at 2.2% annual growth. Notice how slowly the growth starts: it takes five doublings just to get above a 10% increase. Most humans weren’t concerned by this early growth, myself included. In the year 2000, with my linear brain attending to other matters (making money and finding a mate), I tacitly assumed that humanity had 100 years or so to do something about global warming. I wasn’t alarmed, and neither were any of my friends or colleagues.
But as you can see, the early 21st century marks a sea change in growth, with the relentless power of doubling causing human CO2 emissions to suddenly dominate the biosphere’s stable, preindustrial 280 ppm. Today, we’re poised on the brink of explosiveness. This is one reason I’m certain that global fossil-fueled industrial civilization will soon end, one way or another.
I doubt that
fossil-fueled industrial civilization
will continue for much longer.
Population growth underpins most facets of our predicament. Like our bodies, the biosphere is a complex system that requires balance between many parts to function well. Humanity is just one part of the biosphere, a part that has become out of balance with the rest of the system.
Here’s some data. The top pane of Figure 5.1 shows human population from 10,000 years BCE (at which time the population was between 1 and 10 million) until today.8 The bottom pane of Figure 5.1 shows human population from the Renaissance to the present, and United Nation projections to 2100.9 The best exponential fit to data between the years 1500 and 2014 has a growth rate of 1.7%.
The global population growth rate peaked at 2.2% per year in 1963 when there were 3.2 billion people, equivalent to 190,000 new humans per day.10 By 2014, growth had decreased to 1.1% per year, but because there were now more than 7 billion people, this translated to 217,000 additional people each day. (Try to imagine 4.3 births and 1.8 deaths each second.)
The main reasons for the slowing birth rate involve empowerment of women: increased female education levels and increased access to contraception. Correlation between lower birth rates and female education, which can be measured using literacy or enrollment rates, is extremely clear; there’s strong evidence for causation as well.11 When women gain more control over family planning and begin to have career options, families tend to delay childbearing and to have fewer children. In addition, empowering women improves their health and life prospects, as well as those of the children they do have.
Note that the growth rate of CO2 emissions (2.2% per year) is twice the current population growth rate (1.1% per year). This suggests that global emissions are currently being driven in roughly equal measures by population growth and growth in individual consumption.12
Both the US Census and the United Nations expect the world population in 2050 to be 9.7 billion13 and still growing at 0.5% per year (130,000 additional people per day); in 2100, the UN predicts 11.2 billion14 with growth of 0.1% per year (30,000 additional people per day).15 The growth rate is declining, but can Earth sustain 11.2 billion humans?
FIGURE 5.1. World population growth. Top: from 10,000 years BCE to present. Bottom: from the Renaissance to the present, including the UN projection to 2100 and an exponential fit.
As we saw earlier, in the short term, we will move away from fossil fuels. For long-term biospherism, we must also settle at a stable and sustainable population.16 This will be a tall order: biology has given every species an imperative to reproduce, and humans are no exception.
Policies aimed at educating women or encouraging contraceptive use, both in the US and abroad, would help. I’d personally also think long and hard before deciding to bring a new human into tomorrow’s world—even longer and harder than I did back in 2006 when Sharon and I decided to have our first baby, and in 2008 when we decided to have our second. We wanted a third, but we decided against it. The global replacement rate is 2.3 children per woman: if no person had more than two children, the global population would steadily come back down to earth.17
As we’ll discuss below, even the current human population is likely unsustainable. This suggests that, when viewed in the global average, it’s actually irresponsible to have more than two children. Of course, I’m not placing the entire onus of population control on individuals and letting institutions off the hook. Nor do I think that a poor woman in rural Bolivia, with no education or access to birth control, is acting irresponsibly by having more than two kids. However, I am suggesting that privilege carries responsibility, and that those of us with privilege can choose smaller families with only one or two children, or to adopt. We can also support those who decide not to have children at all. Unfortunately, women who choose to be childless still face social stigma,18 whereas I believe they deserve respect for their choice.
At the collective level, it may finally be time for the nations of the world to begin addressing global population in some just and decent way, but this won’t happen until average people recognize there’s a systemic problem. As unpleasant as it is to consider such policy, the only other option—allowing the biosphere to manage our population for us—might be even worse. The biosphere could do this, for example, via continued evolution of viruses targeting developing fetuses. Or it could simply limit our food supply.
Food is a prerequisite for population growth, because humans are literally made out of food. In the industrialized world, crop yields per acre began to grow dramatically after about 1950 and in 2015 were at an all-time high. However, that growth came at a high price to our soil, water supply, and atmosphere. Already yield growth is slowing globally and collapsing in some regions.19 We can’t keep growing more food on a finite Earth, year after year, forever. Instead, global food production will reach a maximum value—peak food—and then begin to decline.
Within a decade, no child will go to bed hungry.
— HENRY KISSINGER, speaking in 1974
By the late 1950s, human agriculture had essentially exhausted Earth’s supply of fertile temperate grassland. The global march of grains that began some 10,000 years earlier had run out of new land to plow, so the focus of farming shifted from expansion to intensification: increasing how much grain could be extracted per acre. New industrial farming methods pioneered in the US permeated global agriculture. In 1968, the director of the US Agency for International Development (USAID) named the shift in agriculture the Green Revolution. In 1970, the biologist Norman Borlaug, known as the “father of the Green Revolution” for his work on high-yielding wheat varieties, was awarded the Nobel Peace Prize. But even Borlaug recognized that ramping up food production was only kicking the population can down the road. In his Nobel lecture, he warned, “The Green Revolution has won a temporary success in man’s war against hunger and deprivation; it has given man a breathing space.... But the frightening power of human reproduction must also be curbed; otherwise the success of the Green Revolution will be ephemeral only.” Borlaug gave a time scale of three decades.20
Four key technologies underpin the Green Revolution: high-yielding crop varieties,21 irrigation, nitrogen fertilizer, and chemical pesticides. A fifth technology is now pushing yields still further: genetically modified organisms (GMOs).22
High-yielding crop varieties are prima donnas, prolific only when given pesticides, fertilizers, and irrigation. Resilience has been bred out of them; they focus energy narrowly on seed production. Without pesticides to protect them from insects, without herbicides to protect them from weed competition and to allow dense planting, and without fertilizers to keep their carbohydrate production in overdrive, they’re out-produced by the more resilient traditional varieties they were engineered to replace.23 Between 1961 and 1999, irrigated acreage increased by 97%, and use of pesticides and nitrogen fertilizer increased by 854% and 638% respectively.24 Today, less than 20% of this nitrogen ends up in our food.25 The rest becomes nitrate pollution groundwater, washes downstream where it causes algal blooms and dead zones, or is blown into the air where it causes respiratory illness and eventually imbalances forest ecosystems.26
Nitrogen fertilizer and chemical pesticides effectively allow growers to treat soil as a dead matrix for holding up plants, turning farms into fossil-fueled food factories. Plants require nitrogen atoms to construct proteins, nucleic acids, and chlorophyll, but nitrogen molecules, which make up 78% of air, have strong triple bonds that render them chemically unavailable to plants. So plants rely on bacteria that are capable of splitting this bond so that nitrogen can be assimilated into amino acids, DNA, and the other building blocks essential to life. Some of these bacteria live freely in the soil, and some partner symbiotically with plants (mainly legumes). This process of making nitrogen available to organisms is called fixation.
In 1908, the German chemist Fritz Haber invented a way to use natural gas to split the N2 triple bond and create fertilizer, opening the industrial age of agriculture. Global fertilizer production, which is fossil-fuel-intensive, grew nearly exponentially until about 1980, at which point the Green Revolution had penetrated most of the world’s grain croplands.27 Today the majority of nitrogen on Earth is fixed industrially; if your diet is typical of industrial civilization, at least one-half of the nitrogen atoms in your body were fixed by the Haber process.28 In this way, our bodies are indirectly made out of fossil fuel. We are what we eat.
Most other aspects of our industrial food system also run on fossil fuels, from processing to packaging to distribution. For example, in 1997, a pound of produce traveled more than 1,700 miles on average before arriving at a market terminal in Maryland, USA.29 This agriculture system, while good at producing huge quantities of food (and extracting profits for vertically integrated multinational corporations), is utterly dependent on fossil fuels. Way back in 1991, it took an average of 10–15 calories of fossil energy to produce one calorie of food in the US.30 One meat calorie required 10–40 times more fossil fuel calories than one fruit or vegetable calorie.31
Unsurprisingly, food prices now follow fuel prices in lockstep (Figure 5.2).32 If fuel prices rise or become more volatile, food prices will follow. Higher prices and higher volatility would both be bad news for the world’s poor.
The Green Revolution was motivated by a vision of ending world hunger. The rapid adoption of intensive fertilization, irrigation, pesticide-supported monoculture, and crop varieties optimized to these industrial methods thereby seized the moral high ground. And indeed it might have ended world hunger—if only humans had shared the food equitably and stopped making so many new mouths to feed. But any population of animals responds to the available food supply—and once again, humans are no exception.33
Supercharging agriculture with fossil fuels has almost tripled the average world grain yield since 1960. The human population has increased in lockstep, almost tripling over the same period. And global food demand is expected to increase by another factor of two or three by 2050.34
Because humans are made out of food, the size of our population depends on the amount of food available to us. Only a small number of species engage in agriculture and can therefore intentionally increase food production; this group includes ants, termites, damselfish, humans, and others. Our agricultural ability perhaps gives the illusion that we have conscious control over the dynamic equilibrium between our food supply and our population. But so far, industrial societies have always chosen to increase the food supply, perhaps both from fear of famine and desire for wealth; and the population has always responded predictably, as would the population of any other species—by increasing.
So the Green Revolution increased the human food supply, driving growth of the human population. As a sort of aside, we can ask whether it reduced global hunger. Hunger turns out to be complex and difficult even to define, let alone measure. According to estimates from the Food and Agriculture Organization of the United Nations (FAO), the number of chronically hungry people in the world has fluctuated near one billion since the 1970s, peaking at over a billion in 1993 and again in 2009, and reaching a low of around 800 million in 2011.35 Because the global population has increased, the percentage of hungry people in the world has decreased, but the actual number of hungry people has remained more-or-less constant. We can’t exclude the possibility that without the Green Revolution the number of hungry people would have been even greater. Nonetheless, it seems fair to say that we’ve done a grand experiment, starting in the 1950s, and we’ve found that throwing more food at the problem of world hunger creates more people, but it doesn’t diminish the number of hungry people.
In any case, the fact is that we’ve been running the global agricultural engine ever faster, creating more humans, more greenhouse gases, and a need for ever more food. This runaway cycle is now facing rising stresses on multiple fronts such as water depletion, soil degradation, and global warming. How long can we keep this up?
Since 1798, when Thomas Malthus published An Essay on the Principle of Population, people have been making dire prediction about hitting agriculture’s limits, a crisis which has been postponed by technological innovations such as the Green Revolution. Because of the inherent unpredictability of technological innovation, these limits of food production remain unclear. Nonetheless, I hold that there’s a physical upper limit on how much food we can produce on Earth, technological innovation notwithstanding; and that we must someday hit a hard biophysical limit to agricultural growth.
In the early 21st century, for the first time, there’s evidence that we may actually be approaching this hard limit. Despite our best technological efforts, one-third of global grain production shows evidence of plateaus or abrupt decreases in yield rates.36 There’s discussion now about the need for a “Green Revolution 2.0.”37 But how far can we push this system? And what will happen when we reach that limit?
Furthermore, we now know that these technological innovations come at a high cost. The fossil-fueled industrial food system is not only causing great damage to natural systems and biodiversity, it has also replaced the more resilient and integrated local food systems that predated it—systems that are increasingly perceived as the sustainable and economical path forward for agriculture.38
Food system resilience increases with crop diversity,39 and local food systems utilize a greater diversity of crop varieties and rely more on locally adapted seeds within the community from year to year (as opposed to seeds for a single engineered variety purchased from a multinational corporation).40 The erasure of local food systems in much of the industrialized world included erasure of grassroots knowledge and infrastructure at the individual level (gardening, canning, keeping chickens, saving seeds, pruning fruit trees) as well as the community level (local farms, cottage businesses, local markets). If the industrial food system does collapse at some point, your survival could possibly depend on whether and to what extent your community has managed to relocalize food production. It will take time to shift to growing food locally and without fossil fuels.
In many regions, humans are pumping groundwater from aquifers far faster than the aquifers can replenish. The Ogallala Aquifer covers a vast expanse of the US high plains from Nebraska to Texas; we’re currently depleting it at nine times its recharge rate (a depletion ratio of 9). Other aquifers in the world are faring even worse. The depletion ratio is 27 for the Western Mexico Aquifer, 48 for the Northern Arabian Aquifer, and a whopping 54 for the Upper Ganges Aquifer, which provides water for Northern India and Pakistan, including the subcontinent’s wheat belt.41
Depletion ratios are well-known, but total water amounts in aquifers are not. If we continue depleting these aquifers, they will someday run dry, but it’s difficult to predict when. However, it’s possible to make such estimates from measurements of bedrock elevation and predevelopment groundwater level. A recent study of the Ogallala Aquifer estimates that, in 2010, 30% of the water was gone, and that farming in western Kansas will peak around 2040 and then decline due to lack of available irrigation water.42 This would transform the landscape of North American agriculture.43
Extraction isn’t the only threat to the world’s freshwater supplies; there’s also global warming. For example, California depends on Sierra Nevada snowpack both for Central Valley agriculture and for the cities of Los Angeles and San Francisco. The snowpack is predicted to decrease by 70–80% by 2070–2099.44 In California, as in many other regions of the world, we’re living unsustainably on borrowed groundwater.
Global warming is predicted to cause deeper droughts in the future, worse than the drought that contributed to the collapse of the Anasazi civilization.45 Aquifers are like shock absorbers for drought; their depletion would amplify drought impact. Depletion in key agricultural regions (such as the US high plains, Mexico, India, and northern China) would have far-reaching consequences: no water, no food.
Soil is amazing, the thin living skin of a planet which would otherwise be a lifeless rock. Industrial agriculture strips the soil of its nutrients, its microbial diversity, its ability to hold water, and its ability to resist erosion. Degraded soils are unable to provide the normal ecosystem services of healthy soils. About one-quarter of the world’s agricultural lands are thought to have highly degraded soils,46 which may cause a significant decrease in crop yields by midcentury.47
Good soil isn’t compacted, has a healthy tilth (soil structure, which includes pores and aggregates), proper drainage, adequate organic material, and adequate nutrients (both macronutrients like nitrogen, potassium, and phosphorous and micronutrients like manganese). Good soil has few disease pathogens or pest insects, and no toxins. It’s a self-organizing system driven by a complex web of plant roots, beneficial bacteria, fungi, and insects,48 with a delicate, water-retaining three-dimensional structure.49
Soil degradation occurs for a variety of reasons, such as soil mining (growing and shipping crops without replenishing organic matter), application of fertilizers and pesticides (which kill soil microbes), tilling (which destroys tilth), compaction, irrigation-induced salinity, monoculture (lack of plant diversity, which affects soil microbes), and erosion. All of these are hallmarks of industrial agribusiness. In addition, urban expansion contributes by paving over living soils.
Degraded soils hold one-half the water of healthy soils.50 Healthy soils act like a sponge, holding water in the root zone, while degraded soils allow water to rapidly descend below the root zone and out of the reach of plants. Depleted soils require more irrigation.
Soils heal slowly, and it will take a sea change in agricultural mindset in order to allow healing to begin. Humans will need to stop thinking of food as a global commodity, and to start seeing it for what it is: a critical interface between humans and the biosphere, our connection to life. We will need economic systems that support farmers who use biospheric methods to produce high-quality food, because switching to no-till and green manure methods can take a few seasons to pay off financially. The sea change may already be underway: in the US, about 35% of cropland is already farmed without tilling, and the idea is spreading.51
Those of us who aren’t farmers can help by buying responsibly grown food, by wasting less of it, and by eating less meat. Even better, we can start growing food, thereby developing awareness of the land. We can become growers of good soil. In my experience, it’s possible to grow good soil on an individual scale through composting and recycling humanure (see Chapter 12). I suspect that the main reason homegrown food tastes so much better than industrially produced food is because of the soil.
Soil degradation is connected to deforestation and global warming. In many parts of the tropics, agriculture degrades soils, abandons the degraded land, clears virgin forests to farm, and repeats. The net loss of 35,000 acres of forest per day52 in turn moves carbon into the atmosphere, accelerating global warming.
The interaction between climate change and agriculture is complex. Crop ranges are shifting, some northern regions will benefit agriculturally, and farmers will adapt. Overall, though, global warming spells trouble for agriculture.
First, as just discussed, global warming is a threat to the world’s supply of freshwater for irrigation.
Second, increasing temperatures and related droughts are already adversely affecting cereal crop yields, and this impact is predicted to deepen.53 Global yields have already been reduced an estimated 6% to 10% (and yields might continue decreasing 3% to 5% per 0.5°C increase in temperature).54 Crop failures caused by heat waves and droughts forced Russia to stop exporting grain in 2010.55 Although corporate researchers are genetically modifying crops for heat resistance, this can only be taken so far: as temperatures increase, eventually sensitive plant molecular systems (e.g., lipid membranes) break down.56
Third, pest and disease ranges are expected to expand with warming temperatures. Fungus, oomycete, and insect pests, normally kept in check by cold weather, are migrating northward at the same rate as warmer temperatures.57
Fourth, as CO2 concentrations increase, our food becomes less nutritious, as vitamin and protein contents decrease.58 This nutrition decrease affects the C3 photosynthetic plants—95% of the plant species on Earth. (The important agricultural exceptions are corn, millet, sorghum, and sugarcane; most other crops are affected.) And the effect is significant: for example, the protein content of goldenrod pollen has fallen by one-third since the beginning of the Industrial Revolution.59
Finally, we can expect greater year-to-year variability in harvests, driven in part by higher variability in precipitation.60
These adverse effects will be partially offset by the CO2 fertilization effect: higher atmospheric CO2 concentrations lead to higher yields, all else being equal.61 While the precise magnitude of the CO2 fertilization effect is still uncertain, we do know it won’t be large enough to offset the losses.62
Meanwhile, demand for food is expected to increase to 150% of 2010 levels by 2030, and to double by 2050.63 The demand increase is driven by increases in both population and consumption, and yield projections fall far short.64 It’s not clear that we have the capacity to double global food production. And even if we did, would we be able to continue this pace beyond 2050? Do we have the capacity to quadruple current production?
Given the complexity of the global food system and its interconnections with global warming, resource depletion, economics, politics, and global population trends, it’s impossible to predict a date for peak food. However, if the population continues to grow, peak food must occur sooner or later. As we approach this peak, the real price of food will increase as demand outstrips supply regionally, contributing to political instability.65 When people can’t eat, the fabric of a society tears—as was dramatically demonstrated by Venezuela’s food crisis, which blew up in 2015.66
Many of us in wealthy nations currently take food for granted. But it seems possible that peak food will be an increasingly important factor in the deep rearrangement of globalized civilization.
We’re not helpless, though. We can grow food ourselves, in our front yards, in our backyards, in community gardens, and in vacant areas. We can create communities capable of feeding themselves without fossil fuels. We can reduce our meat consumption. In these ways, we can gradually transition our agriculture away from industrial monocultures, and toward organic polycultures on smaller scales. This shift will require more of us to spend some time growing food—a practice I personally find rewarding.
In the early 2000s, people concerned about humanity’s unsustainable business-as-usual path seemed to fall into one of two main camps. There were those more concerned about global warming, and there were those more concerned about global economic collapse due to “peak oil,” the end of the era of cheap fossil fuels.
All of my friends, my enemies too Live in the shadows of the dirtiest fuel Burns the land and its people to ruin While wind’s always whistling an infinite tune
— DIRTY PROJECTORS, “Just From Chevron”
By now, though, it has become clear that global warming is the more urgent and perilous of these two dynamics. As Cristophe McGlade and Paul Ekins wrote in the journal Nature, “Although there have previously been fears over the scarcity of fossil fuels, in a climate-constrained world this is no longer a relevant concern.”67 And as we saw in Chapter 4, in order to avoid catastrophic global warming, we’ll need to leave at least two-thirds of current fossil fuel reserves in the ground.
Still, today’s economy is intimately tied to fossil fuels—all economic production requires energy—and as such it is vulnerable to fossil fuel price swings. Indeed, since the 1940s, oil price shocks were the main drivers of economic recessions.68 It’s conceivable that a fuel price spike contributed significantly to the 2008 economic downturn by pressuring the transportation sector, which slowed growth enough to tip over the subprime mortgage pyramid scheme; and it’s also conceivable that in a post-peak epoch, economic growth will reliably trigger fuel price spikes and recession, followed by low fuel prices and a gradual return over several years, in a repeating saw-toothed pattern.69
The next two sections describe how our economy might be vulnerable to the fuel supply. The slower we are to transition away from fossil fuels, the more likely these scenarios are to be relevant.
In the beginning of 2016, oil was below $30 per barrel, whereas in the summer of 2014, it was over $100 per barrel. The main reason for this price drop was overproduction, mainly from the US fracking boom. Fracking was an old technology for obtaining “tight” oil and gas that became economically viable after the price of oil passed $70 per barrel. Fracking continued anyway, even at uneconomic prices, because investors continued giving their money to the frackers.70
Over geologic time, oil flows from impermeable rock formations like shale to permeable formations like sandstone. In the US, we’ve long since tapped out the easy oil in permeable formations; it takes more energy, effort, and money to extract fuels from impermeable (“tight”) formations. Hydraulic fracturing (fracking) is a method for obtaining the tight oil and natural gas. However, fracking wells play out very rapidly, typically after only a year or so. This is why frackers drill huge numbers of wells.71
National or global production is the aggregation of production from many individual wells, each of which ramps up to peak production and then declines. Figure 5.3 shows graphs of US (top) and global (bottom) annual crude oil production.72 From 1920 until about 1960, US production boomed as the permeable oil reservoirs were developed and tapped. As these easy reservoirs played out, their replacements were less accessible. The cost to retrieve each barrel of US oil went up until the US could no longer compete on the international market. Production rolled off, peaking in 1970 and then declining. Then, in 2010 fracking kicked in, creating a dramatic uptick in production.
In the 1950s, M. King Hubbert developed a mathematical theory for the extraction of finite, non-replenishing resources: production ramps up initially, reaches a peak, and then ramps down as the resource becomes increasingly difficult to obtain. Non-intuitively, the ramp-down happens at the same rate as the ramp-up; the faster production rises, the faster it declines post-peak.73
Given our globally connected market for energy, the global economy will of course respond to the global peak. Nonetheless, I found it informative to fit the US data with the sum of two independent Hubbert curves.74 One Hubbert curve fits the conventional crude oil production, which peaks around 1970, and the other fits the more recent fracking production. The Hubbert curves fit the data remarkably well.
No one knows exactly how long the fracking boom will continue, but one report predicts US peaks in both tight oil and gas production before 2020.75 The US government agrees that tight oil production will peak by 2020 “as drilling moves into less productive areas.”76 On the far side of the production peak, Hubbert theory predicts rapid collapse which may cause oil and gas price increases, destabilizing the economy.
As for global peak oil, the consensus among experts is that it will occur sometime between now and 2030. Indeed, it may have occurred already.77
It takes energy to obtain energy: you need fuel to make equipment, drill wells, fracture layers of rock, and refine crude products. The energy returned on energy invested (EROEI) is the ratio of how many units of energy you get per unit of energy spent.
Fossil fuels are becoming more difficult to obtain, and EROEI for fossil fuels is declining rapidly. The EROEI for coal in the US declined from 80:1 in the 1950s to 30:1 in the 1970s.78 Globally, the mean EROEI of oil and gas halved in just ten years, from 40:1 in 1995 to 20:1 in 2006.79 Extracting oil from tar sands is even more energy-intensive: tar sands oil has an EROEI of only about 4:1.80 This is part of a longer global trend of decreasing oil and gas EROEI, which is likely already having a large impact on the global economy.81
Declining EROEI increases the real cost of energy and creates a drag on the economy. Money is essentially a social contract for storing work, and fossil fuels equal work. This essential equivalence between fossil fuels and money is partly why we’re finding it difficult to leave them in the ground.
TABLE 5.2. EROEI estimates for various energy sources.
Source |
Year |
EROEI |
Oil and gas (global) |
1995 |
40:1 |
Oil and gas (global) |
2006 |
20:1 |
Coal (US) |
1950s |
80:1 |
Coal (China) |
2010 |
30:1 |
Tar sands |
|
4:1 |
Hydropower |
|
100:1 |
Wind (w/o storage) |
|
20:1 |
Nuclear (US) |
|
10:1 |
Solar PV (w/o storage) |
|
10:1 |
Corn ethanol |
|
1:1 |
Table 5.2 gives published EROEI estimates for several energy sources.82 EROEIs of renewable generation technologies like solar and wind are low relative to fossil fuels. The numbers here do not include energy storage systems, which would further lower the overall EROEIs for renewables. This doesn’t necessarily imply that our renewably powered lives will be bleak in the future: EROEIs even as low as 3:1 can still provide useful energy to society. But it does suggest that our current systems of energy consumption and production, and therefore our economic systems, will undergo a tectonic shift. The age of nearly free energy appears to be drawing to a close.
Indeed, both the world and US GDP growth rates have fallen significantly over the last 60 years.83 No one knows the exact reasons for this slowdown, but three possible causes are deceleration in population growth, deceleration in labor productivity growth or technological growth, and the decreasing EROEI of fossil fuels. I suspect that the slowdown indicates major cracks in the foundation of the industrial economy: its energy and money systems are becoming increasingly unsustainable.
Apparently capitalism has a structural flaw: money exhibits a gravitational attraction whereby wealth accrues more wealth. The debt-based money system ensures this is so, via interest payments on use of capital. The inevitable result is a black hole of wealth that warps the structures of power, accelerating the process.
When an individual decides to engage in a capital-intensive activity (such as extracting oil from the Earth and refining it into fuel), he or she will find that forming a corporation brings significant advantages. First, the individual is no longer liable for debts or misdeeds; this liability transfers to the corporation. Second, a corporation leverages the wealth of a potentially enormous pool of investors. Third, unlike a human, a corporation can exist perpetually.
My philosophy is to make money.
— REX TILLERSON, former CEO of Exxon Mobil Corporation
Once formed, corporations seek to make as much profit as possible—indeed, they’re legally bound to do so.84 Naturally they seek to pay as little as possible in taxes and to limit any regulation that might impinge on profits. Their only goal is to grow as rapidly as possible.
The politicians who establish taxes and regulations want above all else to be reelected. But effective campaigns are expensive. So the corporations and their wealthy owners offer money; in exchange they ask for changes to laws, regulations, and tax codes. The politician who doesn’t go along will lose that source of funding, decreasing her odds for reelection.
Corporations, then, continuously reshape the legal landscape so as to exert more influence and thus extract more wealth. There are innumerable real-world examples, including Citizens United, a 2010 US Supreme Court decision allowing corporations unlimited funding access to political campaigns;85 the American Legislative Exchange Council (ALEC), a group of corporations and lobbyists that literally writes laws and then gets state legislatures to pass them;86 and international trade deals which exert downward pressure on wages and allow corporations to dismantle national regulations that interfere with profits. As voters, much of this corporate influence is out of our control: the two-party system in the US, for example, has long ensured that almost every candidate with a reasonable chance of winning high office is under corporate influence—Republican and Democrat alike.
This infiltration of the political system brings capital ever more wealth, growth, and control over the halls of power, a positive feedback loop. Systems with such a feedback are inherently unstable. (The agriculture-population system is another example.) With very vigilant control, we can prevent this feedback with checks and balances; but as soon as there’s a lapse in our vigilance, the feedback—wealth’s self-gravity—will again metastasize. We can call this metastasis the corporatocracy. Its building blocks are corporations, wealthy individuals, politicians, and laws. Its essence is the systematized love of money.
Fossil fuel corporations are among the largest and most profitable corporations the planet has ever seen,87 and all industrial extraction of wealth, from agriculture to mining to manufacturing, runs on fossil fuels. Not surprisingly, the corporatocracy views climate action as a threat to its survival. To preserve the status quo, it actively blocks meaningful climate action by controlling policymakers, and by confusing the public by falsely sowing scientific doubt.88
Effective climate action is certainly hamstrung under corporatocracy, which prioritizes rent-seeking over the biosphere. Even without the additional burden of runaway corporatocracy, modern capitalistic democracies would still tend to prioritize economic growth over the biosphere. For example, a 1992 United Nations international climate agreement explicitly says that “measures taken to combat climate change, including unilateral ones, should not constitute...a disguised restriction on international trade,”89 and these priorities have held ever since. Global extractivist trade, and the growth and consumption that are its lifeblood, appears incompatible with meaningful climate mitigation. This is why we see efforts, for example, to put price tags on ecosystem services. I personally fear that these sorts of incremental efforts are too little, too late; and that what we really require is a paradigm shift: instead of viewing the biosphere as part of the human economy, we need to view the human economy as part of the biosphere.
Our industrial society is addicted to exponential economic growth. When growth is down, suffering ensues. People lose jobs, wages stagnate, and the specter of a systematic Great Depression-like unraveling hangs in the air. The need for growth is locked into our political-economic system: politicians need to promise exponential growth to get elected. Some economists even argue that exponential growth is locked into the DNA of our economy at the level of the debt-based money system, which requires growth to service interest payments on debt.90
Anyone who believes exponential growth can go on forever in a finite world is either a madman or an economist.
— KENNETH BOULDING, economist and pioneer of systems theory
And this economic growth requires ever more consumption of energy, habitat, and other natural resources. This has been the case historically, and it’s possible to show that economic growth can never permanently decouple from natural resource use.91 We are embodied, physical beings, and we’ll continue to rely on an embodied, physical economy to meet our needs.
However, no law of physics requires exponential economic growth. We humans are free to organize our societies and meet our needs in other ways. Indeed, most human societies over the course of human existence were not organized around exponential growth.
I believe that humanity’s grand challenge goes beyond global warming. Responding to global warming is an urgent first step. But in order to avoid repeated cycles of unnecessary suffering, of growth and collapse, humanity must somehow move into a stable and harmonious long-term relationship with the biosphere.
First and foremost, we’ll need to learn how to see ourselves as just one part of a vast, complex, and beautiful tapestry of life. We’ll need to respect and value nonhumans just as much as humans. We’ll need to come out of the hubristic mindset of having dominion over nature. As I said earlier, we’ll need to realize that our economic system is a part of the biosphere, and not the other way around. If something we do collectively harms the biosphere, we’ll need to stop, no matter what some corporations or individuals might prefer.
This in turn implies that we’ll need a just and equitable society, free from the tyranny of a wealthy few. Our current system’s existence depends in part on a story to mollify the poor and prevent an uprising: that after some more growth, everyone will be rich; that economic equality for all is just around the corner, if only we run our engines of extraction ever faster. In a non-growing (steady-state) society, this story obviously makes no sense.
We’ll need to learn to measure our quality of life in terms of well-being, not money. We’ll need to reduce our population and learn to keep it steady. And of course, we’ll need to limit our consumption of resources to within the biosphere’s capacity for regeneration.
These are huge changes. They require us to overhaul the deepest levels of our social structures and our collective story, the ways in which we construct meaning. This sea change could only occur if enough of us decide it’s the way to go, if we’re willing to let go of our modern aspirations for convenience and profit above all else, and if we implement it gradually but deliberately. Table 5.3 suggests some of the necessary changes.
I believe that a steady-state economy holds the potential for a better and more satisfying life for all, under a social system that could be sustained indefinitely. But it’s very difficult to see how to get there in the real world via real policies. Policymakers might partially choreograph this huge socioeconomic shift intentionally, if compelled to do so by a grassroots groundswell; but it might also come into being when the current system is reorganized, perhaps unintentionally and catastrophically, in response to forces arising from the limits of the biosphere.
TABLE 5.3. Changes needed for a steady-state economy.
Exponential growth economy |
Steady-state economy |
Biosphere seen as part of economy |
Economy seen as part of biosphere |
Growth and collapse |
Sustainable and regenerative |
Money = quality of life |
Well-being = quality of life |
Money system based on debt |
Local reciprocity |
Takes biosphere for granted |
Values biosphere services |
Biosphere seen as tech-replaceable |
Biosphere seen as irreplaceable |
Externalizes biosphere destruction |
Policies protect biosphere |
Global extraction |
Local production |
Short-term view |
Long-term view |
“Man has dominion over nature” |
“We are one among many species” |
Jobs replaced by machines |
Labor is valued |
Makes a few people obscenely rich |
Social justice is woven in |
The Earth’s biosphere is marvelously abundant, capable of supporting billions of humans. It has given birth to a dizzying variety of species in wonderful and unimaginably strange forms, a psychedelic menagerie. But the biosphere’s abundance depends on balance and diversity.
The biosphere supports us by providing food, water, oxygen, waste remediation, a stable and temperate climate, evolved protection from diseases, and protection from harmful solar radiation. These life-support services are interconnected. For example, you can’t grow food without water; and the distribution of water in space and time depends on the climate. When the human population reaches a size at which any one of these life-support provisions falls below a sustainable level, it has exceeded carrying capacity.
Given this interconnection, and all we’ve discussed in this chapter, I think the question of the Earth’s carrying capacity boils down to this: can we sustain the amount of food we grow today indefinitely into the future?
The twentieth century has been marked by a profound historical development: an unwitting evolution of the power to seriously impair human life-support systems.
— GRETCHEN DAILY and PAUL EHRLICH, 1992
The Earth's biosphere has given birth
to a dizzying variety of species in
wonderful and unimaginably strange forms,
a psychedelic menagerie.
By this measure, it may be that we have already exceeded the Earth’s carrying capacity. It seems likely to me that global food production will be increasingly challenged by aquifer depletion, drought, heat waves, extreme weather, and soil degradation. Our technology allows us to capitalize Earth’s ecological services more easily, but it’s not a substitute for those services. Rising fuel and fertilizer costs will be an additional constraint when the fracking boom ends.
Loss of biodiversity provides a second, independent line of evidence that human impact has already exceeded Earth’s carrying capacity. Diversity is a good measure of an ecosystem’s health. Today we’re in the midst of the Earth’s sixth mass extinction. There were half as many wild animals (vertebrates) alive in 2014 as there were 40 years earlier,92 and today’s extinction rate is about 1,000 times higher than the background rate.93 Humans and livestock account for over 97% of land vertebrate biomass, whereas wild animals account for less than 3%.94 We have essentially replaced the Earth’s wild places with agriculture, the Earth’s nonhumans with humans.
In addressing extinction, many conservation efforts focus on individual species. But we also need to think from a systems perspective. Warming and habitat loss exert pressure on entire ecosystems, which can manifest as pressure on individual species through interconnected processes. For example, moose calves in Maine and New Hampshire are killed by winter ticks, which have exploded due to warming.95 For another, over half of primate species are facing extinction due to the combined pressure from expanding palm oil and rubber plantations, and bush meat hunting.96 Nonhuman animals are quite literally under relentless, systematic attack from a mechanized and militarized global economy of nearly eight billion humans. Focused conservation efforts might slow the hemorrhaging; but ultimately, the only way to avoid the sixth mass extinction will be to address the underlying causes.
If eight billion humans (living and eating as we’re actually living and eating today) is beyond carrying capacity, what’s the sustainable limit? No one knows for sure, but we can make an educated guess. For a lower limit, it’s likely greater than one billion. At the start of the Industrial Revolution in the 18th century, when all the coal, oil, and gas deposits were still underground, the human population was just under a billion. Agriculture functioned on sunlight, water, and manure—not on the Haber process. Although there were regional population collapses before the 18th century,97 globally the biosphere was carrying one billion humans while remaining in balance. Humans hadn’t changed the atmospheric composition yet, fish were still plentiful in the oceans, the bison were in great abundance on the North American plains, and (perhaps most importantly) the extinction rate hadn’t yet started its exponential rise. So Earth’s carrying capacity is likely between one and eight billion. I’d guess the midpoint, around 4.5 billion, give or take a billion.
What do the experts say? According to one estimate, the Earth’s carrying capacity is about 4 billion.98 This estimate was made by considering the area of land (at average global primary productivity) required to support one globally average person, including ecosystem services. According to another estimate, the 1994 global population of 5.5 billion “clearly exceeded the capacity of Earth to sustain it,” and a population of 1.5–2 billion people would be “optimal.”99
If everyone on the planet became vegetarian, we could likely double the number of humans that could sustainably ride on spaceship Earth.100 Because about one-third of all food is wasted globally,101 we could in principle increase carrying capacity by another 25%—about one or two billion people, depending on whether we’re meat eaters or vegetarians—by eliminating half of this waste.
So far, this discussion presupposes the existence of agriculture. Author Jared Diamond has argued that agriculture opened a Pandora’s box of human misery, and that we might have been better off without it.102 As we saw above, the pre-agricultural population ten thousand years ago was no more than ten million humans. By applying technological advances to hunting, gathering, and forest gardening, the non-agricultural carrying capacity would probably be in the hundreds of millions. To reach a sustainable carrying capacity in the billions probably requires agriculture.
But now we can see that if we choose agriculture, we have a deep responsibility to somehow exercise restraint in how we share the biosphere. As the Green Revolution has demonstrated, unstable population growth has so far been intrinsic to the intensive agriculture that we practice, which is brutal to nonhumans in its path and therefore to biodiversity; author Daniel Quinn calls it “totalitarian agriculture.”103 The problem here is not just that our population will collapse when we’ve exceeded our ecological bounds, it’s the risk that our totalitarian agriculture will drive the sixth mass extinction in the process, irreparably impoverishing the biosphere for the next ten million years. Therefore, a sustainable global agriculture requires either a population cap or a land-use cap.
A popular environmental slogan is “Think globally, act locally.” However, I find it difficult to truly grasp global scales. It can feel overwhelming, even paralyzing. I prefer instead to think locally as well as to act locally, in terms of human scales: a garden, a bicycle ride, a community event.
But our predicament is, in fact, global; and it’s important to understand it globally in order to forge an appropriate personal response. Global warming is increasing exponentially: I can begin to systematically reduce my own fossil fuel use and support local, state, and national measures that reduce fossil fuel use. A global economy based on exponential growth is eating the planet alive: I can reduce my own consumption and help build a satisfying stable local economy. Global population is driving all of the above: I can choose to have a small family.
Naysayers claim that our predicament is so big that individual actions don’t matter, thereby justifying their inaction. I disagree, of course; this viewpoint may even be quintessentially evil, if the only thing necessary for the triumph of evil is indeed for good people to do nothing. The naysayers and I disagree fundamentally on the nature of connections between individuals, and feedbacks between individuals and society.
I believe that social change emerges complexly from resonant movements between many individuals. Today, an increasing number of people are looking beyond green consumerism, beyond political parties, to search for ways to live in alignment with the biosphere. This movement, biospherism, resonates with me. I hope this book gives it momentum.
We need to respond, and quickly. We’ve recently entered an epoch of viscerally evident physical changes due to global warming. As the perception of our predicament goes mainstream, I suspect it will trigger social change. But because fear will be one driver of this change, not all of what evolves will be positive for human beings. Grassroots movements such as biospherism can perhaps create channels for directing the coming social change in a positive direction.
Every day is precious, especially in light of our exponentially unfolding predicament. I hope that you’ll join me in using these wonderful days to begin aligning with the Earth, with each other, and with yourself. As more of us change to live in this way, the resilient communities we’ll need to weather the coming storms will emerge.
