“The Most Important Plot Ever” by Thomas Murphy, Energy and Human Ambitions on a Finite Planet, p. 116.

I’ve had a gratifying response to my seven-part series on “the future of humanity”, but I’ve also had more than one request to boil it all down to a single post so all the tl;dr folks out there can absorb the basic argument without too many details getting in the way. Although anyone who knows me knows that brevity is not my strong suit, I’m going to give it a try.

What we have learned is reliably true about climate change and resource depletion

We can begin by asking where the scientific consensus is right now on fundamental questions about the evolving shape of our perilous future. Consensus is not unanimity, but on most questions about the future we are facing today, it is possible to assess a massive body of available evidence and pick a side. Personally, I believe our future will be determined by how well we accept and respond to ten key findings in the scientific literature, findings that are so thoroughly documented and validated that I’m going to suggest we call them facts.

Fact 1: We have built a massively unsustainable consumption-driven civilization on the backs of a uniquely powerful energy source — fossil fuels — that was discovered, exploited, and will be depleted within a nano-moment of planetary history: less than 300 years.

For me, the figure at the top of this post sums it all up. What we think of as “normal” is highly abnormal. We live in a time unlike any in the history of our species. And we know it is ending soon. That’s our context. We cannot deny it, avoid it, or outrun it. We have two jobs: (1) minimize the damage our energy binge is producing (mitigation), and (2) learn how to adapt to the dangerous new world we in the process of creating (adaptation) (source, source).

Fact 2: We know fossil fuels are poisoning our atmosphere, but we also know they are becoming more difficult and expensive to obtain. Within the next several decades, they will no longer be available.

This is the story of EROI (energy return on investment) and the Hubbert Curve. We will not “use up” all the fossil fuels in the ground. Rather, remaining reserves will become harder and harder to extract, they will be of lower and lower quality, and they will become more and more expensive, until they simply require more energy to obtain than they can produce.

This inevitable decline will occur at different timescales for different types of fossil fuels, will impact different regions at different times, and will be visible to global consumers in different ways: as rolling shortages, wild price swings, supply chain disruptions, and political conflict.

The graphic below depicts one estimate of how these processes are likely to produce declining energy availability between today and 2050. Note the big bump at the top of this graph. That’s the proportion of fossil fuels required to produce fossil fuels. Today that proportion is around 15%. By 2050, it is expected to be closer to 50%. Eventually, it will reach 100%, and fossil fuel extraction will end.

Source: “Peak oil and the low-carbon energy transition: A net-energy perspective”, Louis Delannoy et al. 2021.

Fact 3: While we have made some significant progress in transitioning from fossil fuels to renewable energy substitutes, these gains have generally been limited to the production of electricity, which powers only about 20% of the world’s energy needs. They are also occurring very unevenly across the globe.

There are some real success stories here, especially where electrification efforts enjoy political and financial support. To me, this is good news for some, but highlights the specter of inequality for many.

If California, for example, successfully completes its “100% renewable electricity generation by 2045” project, how much better off is it going to be in 2050 than, say, Texas (whose politicians believe the oil will last forever), or Sub-Saharan Africa (where there is little infrastructure to begin with, minimal financial resources, and devastating climate-driven crises to deal with)?

When the Age of Oil comes to an end, we are very unlikely to see a global solution in place. The gap between the haves and the have-nots is likely to be even wider, with potentially catastrophic consequences for those at the bottom (see Fact 8).

Fact 4: In order to transition the other 80% of global energy that derives from fossil fuels, we will have to invent many new technologies that do not exist today.

Energy transition skeptics love pointing this out. I’ve emphasized it as well. We know where fossil fuels are currently indispensable and we know what challenges stand in the way of replacing them.

Scientists have identified seven key sectors where progress over the next few decades will determine how much energy we can produce, and where we can produce it, in our upcoming post-carbon world. Where we succeed or fail in finding substitutes for fossil fuel solutions in these seven areas will define the level of complexity our descendants will be able to build, once fossil fuels are no longer available:

• Non-fossil fuel industrial heating: Can we smelt steel without burning coal? Not yet (source, source). But investments are being made (source).
• Multi-hour, day, and season storage of wind and solar-generated energy: Battery technology and innovative solutions for long-term energy storage are among the most active research areas. (source, source)
• Decarbonization of transport: We need to replace diesel and kerosene (jet fuel) as fuels for long-haul trucks, ships, and planes. So far, minimal progress. (source, source)
• Decarbonization of buildings and construction: “The construction industry remains horribly climate-unfriendly”. (source, but see source)
• Carbon capture and storage: So far, CCS technologies have failed to meet expectations (source). Natural solutions (reforestation, wetland restoration) appear more promising (source), but suffer from long lead times.
• Land and soil repair/restoration: Restoration of land and ecosystems can have significant impacts on climate change (source, source, source). Several ongoing projects show promise (source, source).
• Food production: Key here is finding a substitute for fossil fuel-derived fertilizers, which currently generate ammonia (fertilizer’s main ingredient) using natural gas. Efforts to find a renewable alternative to natural gas have seen some progress, but scalability is still a challenge. (source, source)

If you want to know where we’re heading, keep a scorecard for each of these areas.

Fact 5: How long and how much we continue to burn fossil fuels will determine how hot the planet will get. Only when we stop burning fossil fuels will global temperatures stop increasing.

Since at least 2008, climate scientists have known that global warming is reliably correlated with one variable: total cumulative CO2 emissions present in the atmosphere. They have found, somewhat surprisingly, that the amount of climate warming per unit of CO2 emitted is not significantly affected by either the timing or the duration of emissions, but only by their cumulative amount (source).¹

This means that once we stop burning fossil fuels — that is, once we stop emitting additional CO2 into the atmosphere because we’ve stopped burning fossil fuels — global warming will also stop. However, because temperatures depend on the total concentration of CO2 in the atmosphere, not the rate or timing of emissions, “temperatures are expected to remain steady rather than dropping for a few centuries after emissions reach zero, meaning that the climate change that has already occurred will be difficult to reverse in the absence of large-scale net negative emissions.” (source)

Put another way, we control the shut-off valve for runaway global warming. We may not be able to turn down the heat, but ending CO2 emissions will stop the heat from increasing further (for some nuances, see source).

Fact 6: It’s not just climate change we’re facing, it’s climate change plus resource depletion.

As if cooking the planet were not bad enough, we’re also using up its resources — both renewable and nonrenewable — at unsustainable rates. This fact, even more that the reality of human-caused climate change, is probably the most denied and resisted aspect of the global polycrisis we are now facing.

Resource depletion is hotly denied because it directly challenges perhaps the most deeply held (and ultimately disastrous) belief that powers global civilization today: the belief in limitless economic growth. But the fact is, as Herman Daly expressed time and again as he advocated for a more sane steady-state vs. growth-oriented ecological economics:

“Once you depict the economy as a subsystem of a larger system that is finite, non-growing, and materially closed (with a non-growing throughput of solar energy), then it is obvious that the growth of the economic subsystem is limited by the finitude of the containing ecosystem.” (source)

Resource depletion has two quite different aspects. One is the depletion of nonrenewable resources, described in Fact 2 above. But perhaps just as significant in the long run is depletion of the planet’s renewable resources, thanks primarily to unsustainable overconsumption occurring (and accelerating) in the global North (source).²

Once we accept the fact that our planet has a finite carrying capacity and planetary limits for humanity in the form of biophysical and ecological boundaries that cannot be breached indefinitely, we immediately confront two additional facts:

• We are dramatically exceeding the carrying capacity of the planet (that is, we are in overshoot)
• We are doing so in a highly unequal manner, over-consuming in the rich North while under-consuming in the poor South.

Fact 7: Our consumption of the planet’s finite resources is in overshoot: we are consuming more than the planet is capable of replenishing.

What are the resources we are consuming at unsustainable rates? Here is a short list:

• Fossil fuels and minerals (source)
• Fish and seafood (source)
• Forest products (source)
• Land for livestock and food production (source)
• Biodiversity more generally (source, source, source)
• Fresh water (source)
• Food and grains (source, source, source)
• Building materials: (source, source)

So yes, we are not just using up all the oil, we are using up all the planet.

Fact 8 : Our overconsumption of the planet’s resources is very unequally distributed. The vast majority of consumption occurs in the rich global North, while much of the global South struggles to meet the most basic consumption needs of its citizens.

According to most recent calculations from the Global Footprint Network, humanity’s ecological footprint in 2018 was 2.7 global hectares³ per person, but the planet’s biocapacity⁴ was only 1.6 global hectares per person, resulting in an overconsumption equivalent to 1.2 global hectares per person.⁵ Put another way, to sustainably meet all the demands humanity is currently making on the planet, we would require the resources of 1.8 Earths. But the problem doesn’t end there, because this overconsumption is subject to massive inequalities, both between and within nations.

The magnitude of this inequality becomes visible when we compare ecological footprints across nations. Using the same “equivalent Earths” measure, if the whole world consumed as much as the average American, we would require 5.1 equivalent Earths to meet their needs. This, in turn, reveals the futility of well-meaning efforts to bring the whole world up to the standards the richest among us enjoy today. There is simply not enough to go around.

The combination of a finite world and deep inequality raises the question of fairness. If we cannot grow our way out of global inequality by bringing the poor up to the consumption levels of the rich, the only way we can make the world more fair is by lowering the consumption levels of the rich while raising the consumption levels of the poor. How much of a redistribution is required, and how likely is it to happen?

These questions are addressed in a recent study that deploys the planetary boundaries framework to measure consumption levels across nations. Using a baseline of sustainable global resource consumption of 50 gigatons per year⁶ for a global population approaching 8 billion, this study defines each nation’s fair share of resource use as its share of global population times that 50 gigatons of sustainable available resources. It then compares this fair-share estimate with each nation’s actual resource use, again measured in gigatons of resources consumed per year. The results highlight how severely inequality across nations impacts the consumption that is currently driving both global warming and resource depletion. In the period between 1970 and 2017:

• High-income countries were responsible for 74% of cumulative excess material use (including 27% for the US, 25% for the EU and UK, and 22% for the rest of Europe).
• Upper-middle-income countries were responsible for 25% (including 15% for China).
• The rest of the world (lower-middle-income countries and low-income countries) were responsible for only 1% of the excess resource use accumulated over the period.

The authors reach a conclusion that has been prominently reported in the world’s media (e.g., here, here, and here):

“Our results show that high-income nations need to urgently scale down aggregate resource use to sustainable levels. On average, resource use needs to decline by at least 70% to reach the sustainable range.” (source, p. e347)

How likely is this to happen? The authors bury the lede in a classic example of academic understatement: “It is unlikely that such reductions can be achieved while pursuing economic growth.” (p. e347).⁷

Fact 9: Given our failure to curb greenhouse gas emissions, much of this century’s warming is already baked-in. The infrastructure-poor South will suffer first and most, but its loss of productive capacity will quickly boomerang back on the wealthy North as well.

The prognosis for the global South is not good. Even if we manage to limit average global warming to 2°C, temperatures in vulnerable parts of Sub-Saharan Africa, Asia, Central and South America, and small island nations are likely to get much hotter, causing these regions to experience extended droughts, extreme water scarcity, and food shortages above and beyond what the global North is likely to experience, at least initially (IPCC Summary for Policymakers, p. 9).

As I noted in an earlier post, there are rumblings, especially in wealthy countries ruled by rightwing authoritarian governments or weakened by rightwing authoritarian movements, that there may be a “case against helping the poor,” along the lines proposed by Garrett Hardin in his 1974 “lifeboat ethics” article. Despite deep connections to eugenics and racism, Hardin’s “case” is finding sympathetic listeners among modern rightwing movements like the American Republican Party, which has been promoting a “lite” version of lifeboat ethics for years in their attitudes toward immigrants and, more directly, their reactions to the COVID-19 pandemic. Indeed, rightwing writers and journals are busy laying the ideological groundwork for connecting possible climate change policies to lifeboat ethics.

However, if rightwing “thinkers” believe the devastation of climate change can conveniently be confined to “letting the South go”, they are mistaken. Another recent study, provocatively titled “Imperialist appropriation in the world economy: Drain from the global South through unequal exchange, 1990–2015”, reveals the profound extent to which resource consumption excesses of the North are dependent on a large net appropriation of resources, land, and labour from the South, extracted through price differentials and power asymmetries in international trade.

These asymmetric flows happen today because governments and corporations in the rich North are able to leverage their geopolitical and commercial power to artificially depress the prices of labor, resources and producers in the global South. The resulting dependence on cheap products and labor is staggering: the North appropriates 12 billion tons of “free” raw material equivalents from the South every year, making up 43% of the North’s total annual material consumption. In other words, nearly half of the North’s annual material consumption is net appropriated from the South (source).⁸

These numbers could be off by an order of magnitude and they would still be devastating. If and when the South goes down, the North will soon follow.

Fact 10: Given Facts 1–9, some amount of energy descent from our fossil-fuel peak seems inevitable.

Whether that descent will come from a voluntary decrease in resource demand, an involuntary decrease in resource supply, or some combination of the two, remains to be seen.

How steep our descent is likely to be is going to be determined by the answer to one question: how much of an alternative energy infrastructure will we manage to build out, and where will we build it, before fossil fuels are off the table?

Ten facts lead to one dilemma

The basic dilemma these facts present us with is an optimization problem:

• If, in order to limit global warming, we stop burning fossil fuels too soon, that is, before we have completed our transition to alternative energy sources across all economic sectors (especially the seven sectors identified in Fact 4 above), we risk exiting the end of oil with a significantly lower energy production capacity than we have today.
• If, on the other hand, we burn fossil fuels for too long, either because we take too long to complete a scalable alternative energy infrastructure or because of political resistance, we may increase global warming to such an extent (say, 3–4°C) that we make the post-carbon world essentially unlivable for humans (and most other species).

So when is “too soon” and when is “too late”?

This zone between decarbonizing too soon and decarbonizing too late is likely to be a narrow corridor in time. We can make some informal observations about what might constitute the boundaries of this corridor — when “too soon” and “too late” might be — but such estimates are highly speculative.

To determine when might be “too late” to abandon fossil fuels, much depends on how much oil, gas, and coal remains in the ground, and how long we can continue to extract and burn those resources before they become exhausted, either through depletion or economic abandonment. In all likelihood, the end of the Fossil Fuel Age will not be by choice, but by necessity. We can see already that we will not give up our fossil fuel addiction easily, but will have to be forced to adapt to the new world facing us. Recent research indicates that as of 2018 there were about 3,150 gigatons of CO2 trapped in existing coal, oil, and natural gas reserves, yet to be extracted. However long it would take to extract and burn through that legacy would be a good first estimate of how long “too long” might be.

The important point about ending fossil fuels “too soon” is this: Whatever alternative energy infrastructure we have in place when fossil fuels can no longer power our civilization, that will be the energy infrastructure that powers humanity for centuries to come. Whatever concentration of CO2 and other greenhouse gases we have released into the atmosphere before that moment will determine the amount of global warming our descendants will have to endure for centuries on.

Notes

1. Matthews et al., 2009: “Climate–carbon modelling experiments have shown that: (1) the warming per unit CO2 emitted does not depend on the background CO2 concentration; (2) the total allowable emissions for climate stabilization do not depend on the timing of those emissions; and (3) the temperature response to a pulse of CO2 is approximately constant on timescales of decades to centuries.” (p. 829)
2. Several projects have operationalized the concepts of carrying capacity and planetary limits, including the “Planetary Boundaries” project and the “Global Footprint Network” initiative. Good introductions to how these initiatives are measuring carrying capacity and what they are finding can be found here, here, and here, here, respectively.
3. A global hectare is defined as “a biologically productive hectare with world average biological productivity for a given year.” It includes adjustments for the fact that different types of land (e.g. croplands, pastures, forests, fishing grounds, built-up urban areas) have different productivities. A hectare is equivalent to 2.48 acres, or about the area two football fields.
4. The biocapacity of a given area is defined as “The capacity of ecosystems to regenerate what people demand from those surfaces.” The biocapacity of a particular area represents its ability to regenerate what people demand.
5. Another critical component of a population’s ecological footprint is its carbon footprint. This is “the area of forestland that is required to absorb all the carbon emissions from human activity in excess of what the oceans already absorb” (source). This is by far the largest component of humanity’s ecological footprint, encompassing 60% of the demands we make on the planet, and representing the primary means by which overconsumption impacts climate change. Because there is not enough terrestrial plant life to absorb the CO2 emissions we generate from all our human activities, that excess stays in the atmosphere and produces the global warming we are now experiencing.
6. Why 50 gigatons? The authors note: “Industrial ecologists have proposed that a sustainable boundary for global resource use might be around 50 billion tonnes per year. Global resource use exceeded this level in 1997. This level is generally considered to be an upper-limit boundary; Bringezu proposes a target sustainability corridor of about 25–50 billion tonnes per year (Gt/a) (source). Global resource use exceeded 25 Gt/a in 1970.” (p. e344)
7. I would suspect we are going to see many other obstacles to achieving voluntary demand reduction in the global North: nativism, racism, anti-immigrant sentiment, right-wing political movements, and political leaders beholden to wealthy donors propping up the status quo, to name a few.
8. Each year, according to Hickel et al., the North appropriates from the South a net total of 12 billion tons of raw materials, 21 exajoules of energy, 820 million hectares of land, and 188 million person years of labour (source).