Title image credit: Steve Cutts

In his 1982 book titled 'Overshoot' William R. Catton Jr. describes an example of overshoot from nature. In 1944 29 reindeer were introduced to St Matthew Island in the Bering Sea. Estimates for reindeer carrying capacity in ecosystems similar to St Matthew Island range between 13 and 18 reindeer per square mile. Therefore with an area of 128 square miles St Matthew Island should have had a carrying capacity of between 1,600 and 2,300 reindeer. The 29 introduced reindeer quickly grew in number and in 1957 1,350 reindeer were counted. By 1963 the size of the herd had increased to 6000, well over the carrying capacity of St Matthew Island. After another 3 years the population had collapsed to only 42 reindeer. This example illustrates another key feature of overshoot - degradation of carrying capacity. The die off of reindeer did not result in a post-collapse population just below the original carrying capacity of the land. As Catton describes “...overshoot leads to habitat damage so crash plummets population to a level below that which it might have sustained had it not overshot. An overgrazing herd steals from its own prosperity.”

These ideas of energy surplus, carrying capacity and overshoot are fundamental to the existence of every single species on earth. To understand why humans have long since viewed ourselves as being above these natural laws, we must understand the history of our own ecological success story.

Pre-industrial human history is littered with examples where groups of humans the carrying capacity of the land was exceeded locally, often leading to resource depletion and collapse of the population. Popular examples cited in Jared Diamond’s 2004 book “Collapse: How Societies Choose to Fail or Succeed” include the fertile crescent of Mesopotamia, Easter island and the Mayans. 

In some cases civilizations were able to overshoot carrying capacity in the short term until it caught up with them. Examples of this include the Mayans who supported a large growing population through ever more intensive farming. More nutrients were being extracted from the soil each year then were replaced. After a while the soil’s fertility had been exhausted and crops began to fail (lag effect), contributing (in part) to the collapse of the Maya Civilization. 

There are other examples where civilizations were able to seemingly exceed the carrying capacity of their local area because of trade making up for the short-fall in resource demand by a population. William Catton in his book 'Overshoot' describes this phenomenon as “ghost acreage” which he defines as “the additional farmland a given nation would need in order to supply that net portion of the food or fuel it uses but does not obtain from contemporary growth of organisms within its borders”. Certainly today we see examples of this phenomenon with densely populated urban centers only being able to exist because of large tracts of productive rural land and the daily flows of food into the city. This also occurs at national level with countries such as the UK estimated to only grow 50% of their own food. 

The first and second energy revolutions involved the mining of carbon from renewable sources such as biomass (consumption of wood and animals) and then soil (through agricultural processes). The third energy revolution would involve mining of non-renewable fossilized carbon and the harnessing of exo-somatic energy by an organism on a scale never seen before in our planet’s history.

Fossil Fuels

The third major energy revolution for humankind was the discovery of so-called “fossil fuels”. Whereas earlier human history was supported by ongoing energy “flows” (sunlight, wind, biomass), this new age would become characterized by its use of finite energy “stocks” (coal, oil, gas, uranium etc.). This revolution set homosapiens apart from every other organism on earth in a fundamental way, as humans developed the ability to access solar energy that had reached earth well before they ever existed - energy captured in prehistoric photosynthesis and stored as fossilized sunlight. In addition to our daily solar “income” we could now access the solar “savings account” of fossil fuels to do work. The age of abundance had arrived.

Vaclav Smil identifies the 1500 fold increase in use of fossil fuels during the period of the industrial revolution as the most important factor explaining the advances of modern civilization. To illustrate how revolutionary this change was for homo sapiens consider that one barrel of crude oil (approximately 200 liters) can perform about 1700 kilowatt-hours (kWh) of work. With the average human being able to perform about 0.6 kWh of work in one day, this means that one barrel of crude oil substitutes provides about 4.5 years of human labor. All for the price of just $50-100. Taking this analogy further, the average American burns enough fossil fuel energy to equate to having approximately 200-240 energy “slaves” working for them at any one time. As Nate Hagens points out, globally our annual fossil demand demand of 100 billion barrel equivalents translates to an army of energy slaves 500 billion in number. Early in the 20th century the EROI of oil was as high as 100:1 meaning that for every barrel of oil we spent extracting oil we got 100 barrels of oil back - a huge increase in the net energy available to humans from our hunter gatherer and agricultural past.

This huge increase in energy surplus allowed growth of human enterprise on a scale never seen before. This saw the human population explode from 990 million in 1800 to over 8 billion today. Someone born in 1928 could have witnessed the population quadruple from 2 billion to 8 billion in a single human lifespan. Real global gross domestic product  (GDP) increased during this period over 100 fold, fueled by a 28 fold increase in primary energy use. 

Societal complexity continued to increase as new technologies were developed which acted as a self reinforcing feedback loop. This technology didn’t create more energy or resources but it did allow us to access and harness fossil fuel energy stores in ever more powerful ways. With huge amounts of surplus energy the proportion of the population needed for tasks such as growing food plummeted allowing ever more specialization, setting the stage for the scientific age. This led to a belief in endless human ingenuity and the limitless of possible human accomplishments.

Fossil fuels provides an energy subsidy to the human enterprise which the market prices based only on the cost of extraction. This not only ignores the inherent value based on its energy properties, but also the externalities that come with its use (such as pollution) and the fact it is a finite resource. This led us to build an entire globalized industrialized economy on the premise of ongoing abundant cheap fossil fuel energy. With energy so cheap, and seemingly so endless, we began to live further away from where we worked, manufactured further away from where consumed and grew further away from where we ate. This changed the way we built our cities, designed our technology and interacted with the natural world.

Beyond being a hugely important source of energy, fossil fuels also allowed us to create a huge number of new products that are ubiquitous with the modern age such as plastics, textiles, beauty products and medical products. One of its most important uses was in the manufacture of synthetic fertilizers for agriculture leading to large increases in crop yields as part of the "Green Revolution". An estimated 4 billion people are alive today because of the surplus provided by synthetic fertilizers created with fossil fuels. Our modern food system is now estimated to require approximately 10 fossil fuel calories to produce 1 calorie of food when considering processing, packaging, transport, storage and cooking (an EROI of only 0.1). 

If flows of solar energy were homo-sapien’s consistent but modest income, fossil fuel stocks were a lottery win. This one time windfall of abundant cheap energy provided a huge increase in the carrying capacity of the planet allowing the population to balloon to levels never previously thought possible. While we are right to be concerned about the obvious pollution issues associated with burning of fossil fuels (both air quality and global warming), historically there has been little mainstream attention to the fact that they are a savings account that is slowly being drawn down. Despite the fact we have designed our entire economy and society around the use of fossil fuels, their finite nature means that a fourth energy revolution was always a matter of “when” not “if”. 

The EROI of oil has already decreased from around 100:1 in the 19th century to approximately 20:1 today as it becomes more expensive to find, extract and refine. Discoveries of easy to access oil wells are becoming more rare every decade with the discovery of giant oil fields (those with more than 500 billion barrels) peaking in the 1960’s and 1970’s. Now oil companies are having to chase increasing quantities of deep water and tar sand oil that are extremely energy intensive (the EROI of tar sand oil is estimated to be as low as 3:1 to 8:1) and use technology like fracking to get the last drops out of old fields. 

Total oil production would already be in decline if it weren’t for these new but rapidly depleting “unconventional” sources with conventional oil production looking to have peaked in 2005. While total depletion of fossil fuels might still be a couple of decades off, scarcity due to diminishing returns (and resulting cost increases) are sufficient to cause chaos in our modern economy. When literally everything in the economy has the fingerprints of fossil fuels (from the food we eat, to the products we buy, to how to get around), the price of oil must remain high enough to make its extraction economical for suppliers yet low enough for consumers to afford (either directly or indirectly as it is a factor in the cost of literally everything we purchase). While the conversation around this topic has shifted from discussions of “peak oil” to “peak oil demand” in recent decades, one thing is clear - the fossil fuel age is coming to an end either by design, diminishing returns or depletion - and there is no going back.

The “appetite” of modern homo-sapiens

To understand the impact of the increasing energy and resource consumption of modern humans from an ecological standpoint, one could imagine each generation of human being born physically twice as large as their parents from 1800 to the present day (until they were 28 times larger than their ancestor). And don’t forget that during this period the population of these larger humans also increased eight-fold. As William Catton put it, Earth is being asked to accept not only more people, but also ever “larger” people.

Today the average american consumes approximately 2000 calories of energy directly (as food) but also consumes approximately 200,000 calories of energy outside of their bodies (through the burning of fossil fuels). This means the average american has an exo-somatic metabolic rate equivalent to a 30 tonne animal (think a diplodocus or sperm whale) and they will also consume a total 1.4 million kilograms of minerals, metals and fuels in their lifetime including:

• 2.8 billion liters of petroleum

• 196,000 m3 of natural gas

• 5070 tonnes of clay

• 160 tonnes of coal

• 580 tonnes of stone, sand and gravel

• 23 tonnes of cement

• 9 tonnes of iron ore

• 7 tonnes of phosphate rock

• 12 tonnes of salt

• 464 kg of copper

• 215 kg of zinc

• 1001 kg of Bauxite

• 60.34g of gold

• 393 kg of lead

• 19.8 tonnes of other minerals and metals

In ecological terms, modern homo-sapiens in the western world are the equivalent  of a new species of large super predator that require huge amounts of land to support their existence ("Homo Colossus" as Catton famously dubbed it).

The scientific consensus is clear. We are depleting essential ecosystems faster than they can regenerate and polluting the ecosphere beyond nature’s assimilative capacity.  In other words we have significantly exceeded the carrying capacity of the earth. One only has to read the headlines to begin to get a picture of the vast extent of human’s activities on the planet:

• Global use of materials was 100.6 billion tonnes in 2017 (12 tonnes per year for every person on earth), and it is forecast to rise to between 170 and 184 billion tonnes by 2050. 

• Humans produce 2 billion tonnes of waste annually (270 kg per year for every person on earth). 

• Half of habitable land on earth is currently used for agriculture, replacing a third of all forests on earth and two thirds of all grasslands. 

• Since the rise of human civilization 83% of wild mammals have been lost. Half of all invertebrates have been wiped out in the past 50 years.

• Now 96% of all mammals on earth are humans and their livestock while only 4% are wild mammals. 70% of all birds are chicken and poultry and only 30% are wild. 

• Just 3% of the world’s ecosystems remain intact with healthy populations of all its original animals and undisturbed habitat.

Lag effects

One may ask “don’t we know we are below carrying capacity because we currently have enough food for everyone?”. As mentioned previously overshoot of carrying capacity can occur because of lag effects in positive and negative feedback loops. Thomas Murphy describes this phenomenon well in his blog ‘Do the Math’: 

“Growth is a positive-feedback, or self-reinforcing mechanism: more people result in more reproduction; more industrial capital means more manufacturing; more money means more to invest in fueling additional growth. Negative feedback is self-correcting: overgrazing means less food available, exerting downward (corrective) action on population; machines wear out, diminishing the ability to make more machines; the effects of pollution lead to ills that drive measures to decrease pollution. If the negative-feedback mechanisms are delayed in relation to the positive-feedback mechanisms, overshoot occurs so that the correction will be more substantial when it arrives.

For example, decisions to have children are based on conditions now rather than on the state of the world 30 years later when that person still needs to be fed and is reproducing. Pollution is emitted now in relation to today’s growing industry, although its deleterious impacts may not be realized for decades. The self correction of starvation or poor health may not “inform” the positive-feedback mechanisms until they have had ample time to drive the system far past its limit.”

This delay in feedback loops, and lack of clear signals that one has exceeded carrying capacity, means that the speed at which one approaches biophysical limits is of vital importance and that brings us to the next fundamental idea in the story - exponential growth.

The peril of exponential growth

Albert A. Bartlett once said “The greatest shortcoming of the human race is our inability to understand the exponential function”. Exponential growth has the key feature that the time it takes for something to double in size (the doubling time) is constant. 

To illustrate the unintuitive nature of exponential growth consider taking 30 “linear” steps. For most of us this would mean we would travel about 30m. However if one were to take 30 exponential steps (with each step being twice as far as the previous step this would mean one would travel around the world 200 times with 97% of the distance being covered in the last 5 steps. 

Another popular illustration is the puddle in the stadium. Imagine you are chained to the top level of a stadium and there is a drop of water in the bottom of the stadium that doubles in volume every minute. The puddle starts doubling at 12 noon so that by midnight the entire stadium is full. What time would the stadium be half full? The intuitive answer based on linear growth thinking would be somewhere halfway - maybe around early evening. In fact the stadium would still look very empty around this time with the stadium only being 1/2048 full at 11:50pm, 1/4 full at 11:58pm and then 1/2 full at 11:59pm. Even if you added 7 more stadiums to contain the water these would all be full by 12:03. Such is the nature of exponential growth.

Why is this relevant? Well our economic system depends on constant growth of the economy as a percentage year on year i.e. exponential growth. The growth rate varies over time (and between countries), but most western economies target a growth rate of 3%  which is a doubling time of approximately 24 years. Therefore, even if one didn’t agree with the scientific consensus that carrying capacity has been exceeded, the nature of exponential growth means that we will approach this limit very quickly. In fact even if one were to argue we were only at 50% of the carrying capacity of the Earth, it would only take just over two decades to exceed the carrying capacity at a growth rate of 3%. 

As Richard Heinberg points out in his essay ‘The Final Doubling’ one of the problems with exponential acceleration of consumption is that the warning signs of impending resource scarcity tend to appear very close to the time of actual scarcity.

As alluded to earlier, it was this technological breakthrough that avoided the famines predicted by Paul Erlich and led many humanists to conclude that there were no limits to the growth of humanity. However, the Green Revolution did not defuse Erlich’s Population Bomb. It simply added time to the clock and increased the stakes. Any efficiency in land use from modern agricultural methods has more than been offset by the increase in demand driven by population growth, with total agricultural land use remaining steady. Areas like the Amazon rainforest are still being burned down to clear more agricultural land as developing countries adopt more western diets. 

Borlaug himself was under no illusion that his technological breakthroughs were a silver bullet. In his Nobel prize acceptance speech he warned that this technology had to be implemented wisely and that the Green Revolution had not solved world hunger, it had merely bought us time:

“The green revolution is a change in the right direction, but it has not transformed the world into Utopia. None are more keenly aware of its limitations than those who started it and fought for its success….The green revolution has won a temporary success in man’s war against hunger and deprivation; it has given man a breathing space. If fully implemented, the revolution can provide sufficient food for sustenance during the next three decades. But the frightening power of human reproduction must also be curbed; otherwise the success of the green revolution will be ephemeral only.”

He added later in his life:

“Though I have no doubt yields will keep going up, whether they can go up enough to feed the population monster is another matter. Unless progress with agricultural yields remains very strong, the next century will experience sheer human misery that, on a numerical scale, will exceed the worst of everything that has come before.”

When viewed purely through the lens of solving malnutrition, many would (and do) herald the Green Revolution as a triumph of human ingenuity over nature. However the environmental costs such as biodiversity and habitat loss, pollution and topsoil degradation that came with it cannot simply be ignored and undermine the sustainability of these approaches. 

The Green Revolution raised human carrying capacity to the point where it is estimated that 4 billion people today are only alive because of the increased food production it allowed. However, given the unsustainability of its reliance on finite and depleting inputs, degradation of topsoil fertility and accumulating pollutants can this be considered a true permanent increase carrying capacity or merely a temporary exceedance of it? In seemingly overcoming one limit, has that just enabled an increase in human activity that has resulted in us overshooting carrying capacity in other areas? 

Limits to Growth

In 1972 a group of researchers from Massachusetts Institute of Technology (MIT) published a study called Limits to Growth that sought to understand the behavior of human civilization as a system with various inputs and outputs. The aim of the study was to provide a quantitative analysis of the complex interrelationships between various societal and environmental factors and how these interactions may result in limits to growth. 

A computer simulation model called World3 was developed to study the dynamics of the global economy and its interactions with the environment over a long period of time. The model took into account various factors, including population growth, industrialization, pollution, resource depletion, and food production. It projected the future trajectory of these factors based on different scenarios and assumptions. While the authors were clear that the model was created to understand the behavior of the system rather than predict the future, subsequent work done to compare the model runs with actual observed data showed the model has been remarkably accurate to date.

One of the key findings of The Limits to Growth study was that if one particular limiting variable was overcome, this will just lead to other variables eventually acting as the governing limit to growth. 

For example, the researchers decided to make very optimistic assumptions about resource availability, doubling the amount of resources that humanity had at its disposal and assuming that the use of virgin materials reduced by a factor of four because of improved recycling. However, they found in this model run growth was stopped because of the subsequent pollution created. 

So they reran the model with the assumption of doubled resource availability and pollution creation reduced by a factor of four to account for cleaner technology. This run did indeed avert overshoot and collapse from pollution but it still occurred as a result of food shortages. 

To remedy this the researchers reran the model with the same assumptions about increased resource availability and decreased pollution and assumed that food yields increased by a factor of two. The researchers point out that a lot of these assumptions are very optimistic. For example, even at the time of the study food yields had already increased dramatically as a result of the Green Revolution. However, even with increased food supply, pollution once again became the limiting factor to growth.

Inescapable limits

Many would argue that humanity has in the past overcome limits to growth with technological advances and that this is proof that we continue to overcome limits with technology into the future. This view is problematic for a couple of reasons. 

The first and most obvious is the clear logical fallacy that just because something has happened in the past, that it will happen again. Just because I haven’t died yet, shouldn’t lead me to conclude that I am immortal. 

Secondly it disregards the fact that while technology can raise carrying capacity it can also worsen overshoot. A human with an excavator is capable of a much greater level of environmental impact than one with a spade. History has demonstrated that gains in efficiency from technology are more often than not taken up by additional consumption (a phenomenon known as Jevon’s Paradox). While technological advances are capable of solving some human problems, many of them result in switching one problem for new problems (e.g. the Green Revolution).

Finally there are limits of physics that no technology or human ingenuity is able to overcome such as the laws of thermodynamics. It is the first law of thermodynamics that reminds us that technology cannot create energy. It simply allows us to access and utilize energy for work in ever more efficient ways and use it at a faster rate. As the economist Steve Keen says, technology without energy is a sculpture. Energy is finite (the first law of thermodynamics) and always moves from more useful forms of energy to less useful forms (the second law of thermodynamics). 

In his textbook ‘Energy and Human Ambitions on a Finite Planet’ physics Professor Thomas W. Murphy, Jr. demonstrates just how quickly exponential growth in human activity can come up against hard physical limits. In one exercise Murphy considered a present-day global energy production rate of 18 terrawatts increasing at 2.3% per year (a conservative historical value chosen for the ease of being a tenfold increase every century). He demonstrated that if we were to meet our energy demand with solar panels operating at 20% efficiency (not far below the maximum possible efficiency dictated by the Shockley-Queisser limit) it would only take 250 years at this growth rate before we would need solar panels covering every single bit of land on the earth’s surface. He went on to show that after 400 years at this growth rate, we would have to capture every scrap solar energy hitting the planet using solar panels (oceans included) at 100% efficiency to meet our energy demand. For any techno-optimists who aren’t yet convinced, this exponential growth rate means that within 1,400 years we would need to be consuming all the energy released from our sun and after 2,500 years we would be consuming all the energy from all the 100 billion stars in our galaxy! 

But what about if we were to discover an unlimited energy source that was completely waste free and had minimal land use? Many have heralded nuclear fusion as one such solution. As Thomas Murphy points out, whatever the source of energy is, waste heat is produced from our energy expenditure and acts as a physical limit on our activities. In another exercise assuming a growth rate of 2.3% in our energy use he calculated that the resulting waste heat would be more than the predicted effects of climate change after 200 years and enough to raise the temperature of the earth to boiling point (100⁰C) within just 400 years! 

The cornucopian view of reality held by many neoclassical economists is that there are no limits to growth and no such thing as carrying capacity. Rather, resources are effectively unlimited and any environmental problems caused by a growing global population will be solved by human ingenuity and technological innovation. However as we have discussed, the laws of physics show this belief to be mere childlike fantasy.

Could we keep increasing carrying capacity? Not indefinitely. There are physical limits that no technology can overcome. For every limit we overcome there is another one waiting and we potentially risk undermining the carrying capacity of the natural capital on which we rely in the process. 

This is where green growth comes in. Green growth attempts to solve the problem of physical limits with the theory of decoupling and so-called “renewable” energy generation.

Unfortunately for green growth, study after study continues to point out that absolute decoupling has never occurred before at a global scale and is very unlikely to ever occur. A recent report from the European Environmental Bureau titled 'Decoupling debunked – Evidence and arguments against green growth as a sole strategy for sustainability' found the following:

“The validity of the green growth discourse relies on the assumption of an absolute, permanent, global, large and fast enough decoupling of Gross Domestic Product from all critical environmental pressures. Problem is: there is no empirical evidence for such a decoupling having ever happened. This is the case for materials, energy, water, greenhouse gasses, land, water pollutants, and biodiversity loss, for which decoupling is either only relative, and/or observed only temporarily, and/or only locally. In most cases, decoupling is relative. When absolute decoupling occurs, it is observed only during rather short periods of time, concerning only certain resources or forms of impacts, for specific locations, and with minuscule rates of mitigation.”

The report goes on to highlight seven reasons to doubt that reasonable decoupling will ever be a possibility:

1. "Rising energy expenditures. When extracting a resource, cheaper options are generally used first, the extraction of remaining stocks then becoming a more resource- and energy-intensive process resulting in a rising total environmental degradation per unit of resource extracted.

2. Rebound effects. Efficiency improvements are often partly or totally compensated by a reallocation of saved resources and money to either more of the same consumption (e.g. using a fuel-efficient car more often), or other impactful consumptions (e.g. buying plane tickets for remote holidays with the money saved from fuel economies). It can also generate structural changes in the economy that induce higher consumption (e.g. more fuel-efficient cars reinforce a car-based transport system at the expense of greener alternatives, such as public transport and cycling).

3. Problem shifting. Technological solutions to one environmental problem can create new ones and/or exacerbate others. For example, the production of private electric vehicles puts pressure on lithium, copper, and cobalt resources; the production of biofuel raises concerns about land use; while nuclear power generation produces nuclear risks and logistic concerns regarding nuclear waste disposal.

4. The underestimated impact of services. The service economy can only exist on top of the material economy, not instead of it. Services have a significant footprint that often adds to, rather than substitute, that of goods.

5. Limited potential of recycling. Recycling rates are currently low and only slowly increasing, and recycling processes generally still require a significant amount of energy and virgin raw materials. Most importantly, recycling is strictly limited in its ability to provide resources for an expanding material economy.

6. Insufficient and inappropriate technological change. Technological progress is not targeting the factors of production that matter for ecological sustainability and not leading to the type of innovations that reduce environmental pressures; it is not disruptive enough as it fails to displace other undesirable technologies; and it is not in itself fast enough to enable a sufficient decoupling.

7. Cost shifting. What has been observed and termed as decoupling in some local cases was generally only apparent decoupling resulting mostly from an externalization of environmental impact from high-consumption to low-consumption countries enabled by international trade. Accounting on a footprint basis reveals a much less optimistic picture and casts further doubt on the possibility of a consistent decoupling in the future."

The report concludes that when these seven reasons for skepticism are considered together “...the hypothesis that decoupling will allow economic growth to continue without a rise in environmental pressures appears highly compromised, if not clearly unrealistic.”

Many economists point towards western countries as examples of the fabled decoupling as their economies move towards generating more GDP from digital products and the service economy. The reality of the situation is that these parts of the economy sit on top of, and are supported by, the material economy which is as prominent as ever. The ugly truth is that the west has outsourced a lot of the material economy overseas where the social and environmental costs (not to mention carbon accounting) sit with other poorer countries. Despite the digitization of the world economy, the global use of materials has nearly quadrupled in 50 years, from just 26.7 billion tons in 1970 to 100.6 billion tons in 2017 (12 tons per year for every person on earth), and it is forecast to rise to between 170 and 184 billion tons by 2050. 

Perhaps the principle that all economic activity has an environmental footprint is best demonstrated by the data storage that is associated with every single thing we do online. While the “Cloud” can seem very ethereal and without impact in the material world, data storage now has a greater carbon footprint than the airline industry and almost as much electricity consumption as the UK. A single data center can consume the equivalent electricity of 50,000 homes. Swedish researcher Anders Andraes estimated that by 2025 information and communication technology could account for more than 20 percent of global energy use. That means that right now somewhere on earth there is a literal fire burning that is being used to turn turbines to power the data center that stores all the data associated with your digital activity. Nothing in the economy happens without some energy and resource footprint.

The sort of thinking that is emblematic of the green growth movement with regards to dematerialization is probably best summed up by this quote from Steven Pinker: “Indeed, it’s a fallacy to think that people “need resources” in the first place. They need ways of growing food, moving around, lighting their homes, and displaying information. They satisfy these needs with ideas: with recipes, formulas, techniques, blueprints, and algorithms for manipulating the physical world to give them what they want. The human mind, with its recursive combinatorial power, can explore an infinite space of ideas, and is not limited by the quantity of any particular kind of stuff in the ground. When one idea no longer works, another can take its place”. In the real world humans need energy and resources rather than just “ideas” to provide them with food, shelter and other basic needs.

And, in fact, absolute decoupling on a global level will still not be enough to enable green growth to be viable. As has already been demonstrated, the scientific consensus is we are currently above the carrying capacity of the planet. Therefore, what is actually required is doubling the size of the economy in the next three decades while decreasing the global energy and resource demand. To make green growth viable decoupling would have to meet five requirements:

• The decoupling would need to be absolute, not relative and sufficiently absolute so that our energy and resource demands go back below safe planetary boundaries.

• The decoupling would need to be achieved for all environmental pressures, not just carbon emissions.

• The decoupling would have to occur globally not just locally within the boundary of one country’s borders.

• The decoupling would need to occur at sufficient pace to address the urgency of the environmental crises we face. There is no ability to wait on unproven technologies that may appear in 50-100 years time.

• The decoupling would need to be able to be sustained indefinitely.

Problem #2 - “Green” technology is not environmentally guilt-free

Proponents of green growth believe that the electrification of our economy to achieve our decarbonisation goals is a large part of how we will achieve decoupling (commonly referred to as the “green transition”). Among other things, this requires technology like electric vehicles powered by “renewable” energy sources such as wind and solar. When viewed only through the lens of climate change, this technology might make sense as a solution to avoid further increasing carbon emissions. However, when taking a wider view of environmental impact and planetary boundaries, there are legitimate concerns that we might be simply swapping one environmental problem for another. 

Green technology is very material intensive. For example a battery for a single EV requires processing of 40 tonnes of ores and, given the low concentration of metals in their ores, the extraction and processing of 225 tonnes of raw materials (source). A single fossil fuel gas turbine the size of a residential home can produce enough electricity to power 75,000 homes. To replace this energy output it would be necessary to install at least 20 wind turbines covering 10 square miles of land. These turbines would need to be approximately 500 feet tall and require a combined total of around 30,000 tons of iron ore, 50,000 tons of concrete, and 900 tons of nonrecyclable plastics for their blades (In contrast, the gas turbine only requires roughly 300 tons of iron ore and 2,000 tons of concrete). Additionally, the 20 wind turbines would require about 1,000 tons of specialty metals and minerals, including copper, chromium, and zinc, whereas the gas turbine only needs around 100 tons of these materials. While solar installations require less land than wind turbines, they use around 150% more cement, steel, and glass (source). 

Calling solar and wind energy generation “renewable” is a bit of a misnomer. The solar and wind power from which they derive their energy is renewable but as Nate Hagens has suggested, it would be more accurate to call them “rebuildables”. This is because as with all machines they wear out and need to be replaced eventually. Their current lifespan is approximately 25 years (only 10 years for batteries). 

This requires the continual mining, processing, transporting, manufacture and disposing of billions of tonnes of materials, much of it not able to be economically recycled. By 2050 the amount of old solar panels will be twice the weight of all today’s global plastic waste (much of them unrecyclable) and over 3 million tons per year of unrecyclable plastics from worn-out wind turbine blades will be discarded (source). By 2030, more than 10 million tons per year of batteries will be sent to landfill. Even if we were able to recycle 90% of all the materials from this technology, it would only take 6 generations before we had 50% of the material we started with.

Another problem is the materials needed for green technology are finite, take a long time to extract and may not even be available in the required quantities to manufacture the first generation of them, let alone subsequent generations. 

In a recent report for the Geological Survey of Finland, Associate Professor of Geometallurgy Simon Michaux (who has a PhD in mining engineering) attempted to quantify the mineral and metal requirements of the green transition. The results of that study summarized in the tables below paint a stark picture about the feasibility of the green transition. One generation of green technology (assuming that energy demand does not increase at all from 2018 levels - which it will) would require 4.5 billion tonnes of copper, almost 1 billion tonnes of lithium and over 10 million tonnes of rare earth minerals. Global reserves of copper and lithium are only approximately 19% and 2%, respectively, of the required amount needed for one generation of green technology (and would be as much copper as we have mined in all of human history). It would take us approximately 200 years to mine the amount of copper needed at 2019 production rates and almost 10,000 years to mine the lithium required. 

Neoclassical economists will explain away this problem of scarcity of inputs for green technology with the idea of infinite substitutability. That is, as the price of something increases as it becomes more scarce, this will lead to substituting it with another material. The problem with this idea is the physical reality is there are only so many elements in the periodic table and the timeframes involved in switching materials and technology. Again, it is not just about what is technically possible, but what is economically and practically possible within the transition timeframe that is required (20-30 years). While production rates will likely rise as a result of increased demand (and prices), mining is a capital intensive industry and a new mine can take between 15-20 years to open. 

Michaux’s report concludes: “replacing the existing fossil fuel powered system (oil, gas, and coal), using renewable technologies, such as solar panels or wind turbines, will not be possible for the entire global human population. There is simply just not enough time, nor resources to do this by the current target”. Some have criticized the assumptions made in Michaux’s work as overly-conservative, especially with respect to battery storage. Even if that were so, the natural question would be how many generations of this technology could we actually build - noting that every generation will need to have twice the generative capacity of the prior? 

These criticisms miss the broader point being made by Michaux’s work. As discussed for fossil fuels, metals used for manufacturing green technology will be subject to diminishing returns as the easiest deposits to mine are depleted first. Copper grades have already decreased significantly from about 3% at the beginning of the 20th century to about 0.6% today making the process more expensive and energy intensive. It is not a question of whether it is possible to obtain the necessary quantities of metal, but whether it will be economical to obtain them. This is where ideas like mining asteroids for metals fall over. Sure you could theoretically do it, but it would not be affordable for consumers. In the case of energy generation technology would result in an EROI below 1:1 so would not make any sense.

Notwithstanding any of these concerns about metal availability, the other often overlooked point is that the energy involved in the mining, manufacturing, shipping and construction of the first generation of green technology will be generated by burning fossil fuels. The larger the first generation of green technology is to meet our growing energy demand, the harder it will be to be able to meet our emissions reduction targets. While solar panels might be relatively cheap when manufactured by burning coal (as we currently do), we have yet to see the cost of a solar panel made with energy generated from other solar panels.

The environmental footprint of green technology and constraints in availability of materials has largely been ignored in the green growth paradigm. Rapid expansion of wind and solar generating capacity, storage and distribution will require vast amounts of concrete, steel, copper, plastics, lithium, cobalt, nickel, graphite, rare earth metals and involve a huge amount of carbon emissions for the first generation. There is no consensus among experts that we even have the required quantities of these materials, and even if we did, accessing them would likely have hugely detrimental environmental effects. Diminishing returns in metal availability will mean the cost of this technology will continue to rise while its EROI will continue to decrease. 

When considering the planetary boundaries model, green technology only addresses overshoot with regards to climate change (and resulting ocean acidification) and either ignores, or potentially contributes to a worsening of, five other planetary boundaries. While this technology remains a necessary part of our transition away from fossil fuels we cannot use it indiscriminately or view it as having no environmental cost.

Problem #3 - Green energy is not a like for like substitution with fossil fuels

Another problem with the green transition is that electricity generated by renewables has different energy properties than fossil fuels, meaning that it will never be a like for like replacement.

While electricity has a higher exergy than fossil fuels (more useful energy because less is lost as heat), storage and transmission of electricity is difficult compared to the portability of fossil fuels. $200,000 worth of Tesla batteries, which collectively weigh over 20,000 pounds, are needed to store the energy equivalent of one barrel of oil. A barrel of oil, meanwhile, costs approximately $100, weighs 300 pounds and can be stored in a $20 tank. 

Fossil fuels also have the advantage of being very energy dense. Using the example of gravimetric density, diesel has a density of 46 megajoules per kilogram MJ/kg), coal has 30 MJ/kg while a lithium ion battery has 0.5 MJ/kg (source). Hydrogen is being proposed as a potential alternative for heavy fuel in aviation, shipping and trucks and has a relatively high gravimetric density, yet its volumetric density (MJ/L) is almost three times lower than fossil fuel equivalents. This is why liquid fossil fuels are so hard to replace for use cases like transportation where both the weight and volume of the fuel are key to economical alternatives. 

Industrial processes that need very high heat — such as the production of steel, cement, and glass — pose another challenge. Steel blast furnaces operate at about 1,100° C, and cement kilns operate at about 1,400° C. These very high temperatures are hard to power with electricity. Ironically, the melting and crystallizing of silicon for the manufacture of solar panels is one such process which is hard to achieve without fossil fuels which is why coal is currently used in this process.

When it comes to energy generation wind and solar are also highly intermittent meaning they do not always produce electricity. An electricity system powered purely by wind and solar would need to be sized to meet both peak demand and to have enough extra capacity beyond peak needs in order to produce and store additional electricity for when the wind isn’t blowing or the sun isn’t shining. Studies show that this would result in a energy system needing three times the capacity of a fossil fuel energy system. In other words we will need to build 3 kW of wind/solar generation capacity for every 1 kW of fossil fuel capacity we replace. 

While some might argue that wind and solar will continue to improve as they have in the last couple of decades, there are physical limits to how efficient they can get meaning future efficiency gains will be minimal. The physical limit for silicon photovoltaic (PV) solar panels is a maximum conversion of 34% of photons into electrons (called the Shockley-Queisser Limit). Currently the best commercial PV technology today exceeds 26%. The physical limit for a wind turbine is a maximum capture of 60% of kinetic energy in moving air (called the Betz Limit). Commercial turbines today exceed 40%.

Without fossil fuels we are going to have to replace things like synthetic fertilizer, jet fuel and diesel with very energy intensive alternatives. As mentioned previously hydrogen has been proposed as an alternative fuel for aviation, trucking and shipping. So called “green” hydrogen can be produced by using “renewable” electricity to split water atoms into their hydrogen and oxygen components (in effect the reverse of the combustion process). This hydrogen can be burnt as a fuel for transportation and is also being proposed to create “green” ammonia to create the synthetic fertilizers on which our modern food system relies. The problem with “green” hydrogen is that creating breaking apart water atoms to get the hydrogen requires a large amount of energy. For every 100 kW of energy put into the process it produces the equivalent of 38 kW of usable energy, so it runs at an energy loss. 

However, one of the biggest challenges with renewable energy is its energy return on investment (EROI). As we established earlier it takes energy to get energy and EROI is a commonly used measure of the ratio of energy invested to get an energy return. A lower EROI means the energy source will produce a lower level of useable or net energy. The graph below shows how EROI of an energy source corresponds to their net energy percentage  (the proportion of usable energy left over after paying energy costs). Currently oil and gas have an EROI between 20:1 and 30:1 which results in a net energy around 95% (noting that the EROI of oil continues to drop as we deplete the higher quality sources so it is not a viable long term solution). At this level of EROI there is not much change in net energy for a given decrease in EROI. However, net energy begins to drop rapidly as the EROI of an energy source gets below 10:1. 

Without storage, the EROI of wind is estimated to be up to 18:1 while the EROI of solar PVs is estimated between 12:1 and 6:1 (source). The EROI of both technologies would be lower when battery storage is considered (to deal with the issue of intermittency) and when high EROI fossil fuel energy sources used in their manufacture are replaced with carbon free low EROI alternatives. Nuclear energy, which is often touted by techno-optimists as the silver bullet to our carbon free energy woes, isn't much better with an EROI of about 14  (source).

A 2018 study in the peer reviewed journal ‘Nature’ concluded that the effect of all of this is that a low-carbon transition would probably lead to a 24–31% decline in net energy per capita by 2050. A Charles Hall summarized the implications of this concept (known as “Energy Descent”) in a 2014 study: 

“The EROI of our most important fuels is declining and most renewable and non-conventional energy alternatives have substantially lower EROI values than traditional conventional fossil fuels. At the societal level, declining EROI means that an increasing proportion of energy output and economic activity must be diverted to attaining the energy needed to run an economy, leaving less discretionary funds available for “non-essential” purchases which often drive growth.”

Even if we wanted to continue growing the economy into the future, it is likely that there will not be enough net energy available to society to do so. I would argue that declining EROI of fossil fuels, and the increasing metabolic energy cost to maintain our increasingly complex society, has already caused real growth to slow down if not already cease at the back end of the 20th Century. Given that we have grown debt at $3 to every 1$ of GDP created during this period, this recent growth is artificial- it has been facilitated by financial transactions of newly created money (in the form of debt) that have no backing of “real” wealth. 

This is borrowing from the future and creating monetary claims on real products and services we know we cannot fulfill with the energy and resources we have available to us. The dream of endless economic growth died decades ago but we are propping up the system with increasingly large debts and trying to financialize an economy, which at its core relies on the trading of actual real physical things to meet human needs.

Problem #4 - The engineering reality of the Green Transition has been hugely underestimated

The green transition will require the construction of huge amounts of infrastructure. Currently electricity only makes up about 20% of our total primary energy demand with the other 80% of energy coming directly from fossil fuels (e.g. the petrol you burn in your car). The higher exergy of the electricity created by renewable energy generation helps close the gap somewhat here (a lot of that primary energy from fossil fuels is wasted as heat) but the lower EROI of renewables puts them on the back foot. As does the fact that hydrogen will likely be part of our energy mix and as we discussed previously this acts as a very poor energy carrier. This means globally we will need to increase the size of the electrical grid to generate and transmit five times the amount of energy we do now.

Simon Michaux’s study on the availability of metals to enable a green transition also looked at how much electricity would need to be generated by a renewable energy system to replace our current fossil fuel system. Assuming 2018 energy consumption (i.e. no growth in energy demand), Michaux estimates we would need to increase our non-fossil fuel electricity generation by almost a factor of five, from 10,000 Twh to 47,000 TWh. He estimates that to replace the 46,423 power stations run by oil, coal, gas and nuclear energy would require the construction of 586,000 power stations run by wind, solar and hydrogen. That’s over ten times more power stations than the current system due to the lower power density of renewables. If we have any increase in energy demand in the next 20 years - which as we have established is highly likely, if not certain - the target will be even further away.

The graph below shows the amount of energy provided from different sources over the past 200 years. Despite the theories about decoupling our energy demand has been increasing each year at a rapid rate since the 1950’s. The ever increasing size and scale of our energy system creates an inertia that is hard to overcome with substitutions. Despite more and more solar and wind capacity being added to our energy grid every year, it is being outpaced by energy demand. That means solar and wind are not actually replacing fossil fuels, they are being added on top of them to feed our ever increasing energy appetite. Despite all the COP meetings (we’re now up to COP27), the year 2022 involved burning more oil, coal and gas than in any year in human history. 

Another example of the lack of understanding of the engineering reality of the green transition is direct air capture (DAC) technology. Direct air capture involves fans sucking carbon dioxide out of the atmosphere. While this technology has not been proven at scale, currently all IPCC RCP climate change scenarios assume this technology will be developed and implemented. Currently there are about 20 DAC plants in the world with the largest one able to capture 4,000 tons of carbon dioxide a year (roughly equivalent to annual emissions from only 800 cars). Some studies estimate that to meet our climate goals we will require DAC plants to sequester 30 Gt of carbon dioxide annually. This is almost as much as our annual CO2 emissions and, with yet to be developed technology which assumes DAC plants could sequester 1,000,000 tonnes of carbon dioxide each per year, would require 30,000 plants. For context that’s more than the number of airplanes ever manufactured and double the amount of natural gas plants ever built. Each plant would need 2 billion kWh which is enough to power 188,000 American homes for a year. 

In summary, the engineering reality of the green transition has been completely underestimated. Even if we were to assume no growth in energy or resource use, the scale of the task is no less than increasing the number of power stations by a factor of ten, retrofitting the grid to be able to transmit five times more electricity, retrofitting every single industry that relies on fossil fuels for manufacturing heat and replacing or retrofitting every single car, plane, train, ship on the planet - all in the next 20 to 30 years. As previously mentioned, the first time we do this will be by burning fossil fuels. If we continue growing our energy demand at present rates the task could be twice as large in 20 years time (which we will without absolute decoupling). Despite all the feel-good news stories about how much renewable energy is being added to the grid, the reality is this is not even keeping up with the growth in our energy demand, let alone actually reducing the amount of fossil fuels we burn.

A key feature of green growth is the idea that technological solutions will save us. These proclamations aren’t often given any degree of scrutiny or critical thinking. Some key questions to ask about any technological fix:

• How much energy is required?

• Can it be scaled within reasonable time frames?

• What non-renewable inputs does it need and what environmental damage might it cause?

• What are the potential unintended consequences of this technology (first order, second order, third order effects etc.)?

• If it increases efficiency will this just lead to more demand (Jevon’s Paradox)?

• For energy sources, what is the EROI?

Myths of growth

Before we summarize the problems with Green Growth, I thought it would be worth debunking some of the common arguments neoclassical economists make about the necessity of economic growth

Myth #1: “We need to continue growing to create the wealth to afford a green transition” 

This argument ignores the fact that this leads us to chasing our tail - growth creates more energy demand and therefore requires deployment of more green technology. In this sense growth actually makes the green transition more expensive and less affordable. We currently have vast amounts of wealth and yet very little of it, relatively speaking, actually gets invested in the green transition. Each year, for example, almost a trillion dollars is spent on advertising trying to convince people to buy more stuff.

Myth #2: “The more we grow, the less environmental footprint we will have”

This is based on the idea of the Environmental Kuznet’s Curve. The theory behind the Environmental Kuznet’s Curve is that in the early stages of industrialization of a country, economic growth results in a worsening of environmental degradation as industrial activity (largely manufacturing) increases at a time when environmental degradation may not be a high priority. However as per capita income rises there is a turning point where environmental degradation starts to decrease. as the country moves to more of service economy, adopts cleaner technologies, and implements environmental regulations. 

While this theory might sound good, the fact is most developed countries have a very high environmental footprint and are only able to transition to a “service economy” by outsourcing manufacturing to poorer countries overseas. This is effectively just offshoring the environmental degradation. Again the empirical evidence for this theory simply does not exist. For example, countries with the highest GDP are also those that have the highest carbon dioxide emissions and highest resource uses in the world. While better technology can result in more efficient energy or material use, efficiency without sufficiency can actually result in more energy or materials being consumed because of rebound effects (Jevon's Paradox).

Myth #3: “GDP growth is required to increase living standards and increase well being” 

GDP has long been used as a proxy of human wellbeing. This is despite Simon Kuznets, who originally developed GDP warning that "the welfare of a nation can scarcely be inferred from a measurement of national income as defined by the GDP". Robert F Kennedy once astutely remarked that GDP “measures everything in short, except that which makes life worthwhile". 

Despite the pervasive belief that higher GDP makes us happier and healthier, evidence suggests this is mostly not true. Once basic needs are met, various other societal factors aside from GDP are much more important in determining human wellbeing. Spain for example has half the GDP per capita of the United States yet outperforms the US on virtually every social indicator and has a life expectancy that is five years higher. The graph below shows that despite GDP per Capita increasing by almost a factor of four in the US since 1945, the percentage of very happy people remained unchanged. As Peter Victor has remarked "Americans have been more successful decoupling GDP from happiness than in decoupling it from materials and energy".

The notion that developed western nations need to keep growing GDP in order to improve social outcomes is simply not supported by the evidence. Using GDP as a proxy for human wellbeing is a causation/correlation error by economists.

Growth is also used to avoid having to actually address wealth inequality by invoking the idea that a “rising tide raises all boats”. However, according to Oxfam, “82% of all growth in global wealth in the last year went to the top 1%, while the bottom half of humanity saw no increase at all. The research is also clear that income inequality within society results in a decrease in life satisfaction.

The reality of the matter is neoclassical economists know our debt based economy must continue to grow so people continue to lend money knowing that future growth will be able to repay that debt. That is the reason that they insist we have to grow. This is what is called the embedded growth imperative of our economy. However, rather than engaging in the futile pursuit of trying to bend physical reality to fit our current economic system, we should be reforming our economic system to conform to our physical reality. 

Summary of the problems with green growth

Fundamentally the problem with green growth is it is divorced from the physical reality of the biosphere within which the economy exists. The one time bonanza of fossil fuel energy has led some to believe that the rise in prosperity over the past 150 years is a result of human ingenuity and technology, rather than the product of an unprecedented rise in surplus energy available to our species in the form of fossilized sunlight. Having reduced economic activity to nothing more than ones and zeros in a digital ledger, economists mistakenly think that we can simply extrapolate what has happened in the past into the future and what has happened in the digital world into the physical one. At its core green growth maintains the extractive relationship of man over nature.

The immense scale of infrastructure for a green transition has been totally underestimated and green technology that is necessary to transition away from fossil fuels has been completely misappropriated and used to perpetuate the status quo of environmental degradation. The conversation around solutions to the environmental crises should not be about what may be theoretically possible in some distant future with infinite energy and resources but about what is physically, economically and practically possible within the transition timeframe that is required (20-30 years). Technology will play a critical role in addressing the current predicament, but it is no silver bullet that will allow us to continue growing endlessly with no environmental consequences.  

Perhaps one of the conclusions of Simon Michaux’s report summarizes it best:

“Current thinking is that European industrial businesses will replace a complex industrial ecosystem that took more than a century to build. This system was built with the support of the highest calorically dense source of energy the world has ever known (oil), in cheap abundant quantities, with easily available credit, and unlimited mineral resources. This task is hoped to be done at a time when there is comparatively very expensive energy, a fragile finance system saturated in debt, not enough minerals, and an unprecedented number of human populations, embedded in a deteriorating environment. Most challenging of all, this has to be done within a few decades. It is the author’s opinion, based on the new calculations presented here, that this will likely not go fully as planned.”

Now let me be clear, what I am not saying is that technology such as solar and wind should not be used or that we should continue using fossil fuels. Solar and wind power are certainly a crucial part of the solution, at least in the short term, but we are misappropriating them. We need things like solar power and wind power but we need to pair these with huge decreases in our energy use and recognise the environmental footprint they have. Fossil fuels offer energy density, flexibility and portability that no other known source of energy can match. We cannot simply substitute them with renewables and continue with our way of life. The tool is correct, but the application is wrong. 

It would be like living 15 miles from work and switching the car you use to commute with a bike. While it is still possible to do it with different technology, it would make a lot more sense to move to a suburb closer to where you work to shorten the commute. Instead we are arguing the bike is no different from a car and are proposing to move to a suburb even further away.

The Post growth pathway means reducing our environmental footprint back below the carrying capacity in a controlled manner that allows us to ensure that basic human needs are met. Achieving human wellbeing while not degrading the life supporting capacity of the planet are the two central pillars of a post-growth economy. These two goals do not need to be at odds. In recognising the reliance of human survival on the environment, one can consider environmentalism an inextricable part of humanism (just like altruism can be in service to hedonism if one aims to maximize their sense of happiness by helping others). 

The green growth pathway is really a pathway of overconsumption and collapse. The longer we remain above carrying capacity and the larger our overshoot, the more carrying capacity will be eroded and the deeper a collapse in our standard of living will be.

Some will say that post-growth is politically impossible. Maybe so. One only has to look at how Jimmy Carter fared against Ronald Reagen to see what can happen to a politician who tells the truth about our environmental situation versus one who tells voters what they want to hear. That is the seduction of the green growth narrative. Who wouldn’t want to think they can continue to consume as much as they want with no environmental consequences? While it will no doubt be a challenge and require sacrifices to achieve a post-growth future, that is no reason to not do what is necessary for our survival. It certainly is a lot easier to do the politically improbable (governed by laws of human behavior) than attempt the physically impossible (governed by natural laws).

While the focus of this article is the “why” of post-growth, not the “what” or “how” I would highlight a couple of points to avoid the common straw man arguments against post-growth movements. 

Post-growth is not austerity nor recession. Austerity is when governments reduce spending. Post-growth movements like “degrowth” include downscaling of private luxuries such as private jets and mansions but have government provision of “universal public services” such as high-quality health care, education, housing, transportation, internet, renewable energy and nutritious food as a central tenant. Recession is when an economy that has an embedded growth imperative stops growing, causing a chaotic loss of market confidence, job losses and business failures. Post-growth includes reforming the economy so it no longer has to grow to simply avoid collapsing in on itself. When jobs are based around meeting human needs in the real economy rather than a highly financialized economy, instability of the system is reduced, not worsened. 

It is also crucial to highlight that movements like degrowth stress that, while many wealthy western nations need to reduce their environmental footprints, some developing nations will need to continue to develop, and in some cases grow their economy, to ensure that basic human needs are met. This is shown through alternative economic models like the doughnut economy.

It may be the end of the age of abundance but it doesn’t have to be the end of human prosperity. After all, when did we start to believe that, beyond meeting one's basic physical needs, prosperity was about obtaining more stuff at the expense of family, relationships and community? As Timothée Parrique says, the task is to decouple wellbeing from environmental harm, not GDP from emissions.