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Unsustainable Goose Chases

February 28, 2024

As we look toward the uncertain future, it may occur to some among us that we’ll need energy on Mars. How are we going to get it? Presumably Mars has no fossil fuels—although on the plus side its atmosphere is already 95% CO2, compared to Earth’s 0.04%, so they’re likely to be less uptight about carbon emissions on the red planet.

At this point, we could launch into an extensive discussion, full of quantitative detail and analysis about the solar potential: insolation, materials availability, dust storm mitigation, and on and on. But the real answer to how we will get energy on Mars is probably: we won’t. We’re extremely unlikely to set up a permanent presence on Mars, if humans ever even go there at all. So the exercise would be of questionable value.

I feel similarly about discussions of full-scale renewable energy and associated storage and grid shenanigans. How will we rise to the challenge to keep modernity powered into the future? In all likelihood, we won’t. Besides the misdirection of “inexhaustible flows,” keeping modernity powered by any means looks like game-over for ecological health, and therefore humans, if pursued at all costs. So, enough with the fantasy schemes.

Why so bold? Glad you asked.

Past posts of mine have dealt with the question of what sustainability means, and associated timescales:

  1. Ultimate Success: thinking 10,000 years ahead, what’s still possible?
  2. Can Modernity Last?: an attempt to synthesize why continuance is not in the cards
  3. Sustainable Timescales: the relevant scope is that of biological evolution
  4. Inexhaustible Flows: the dead end of materials-hungry “renewable” energy technology

Additionally, The Simple Story of Civilization frames the current epoch as so mind-numbingly new and rapid that it boggles the mind how we could ever think of modernity as a normal time that might have staying power, rather than a fireworks show. It’s only because that’s all our short lives have shown us.

Can We Get Back to Sustainable?

I characterize previous modes of human lifestyles on the planet as follows, in reverse chronological order.

  • Present (modernity): UNSUSTAINABLE!
  • Post-Enlightenment: unsustainable
  • Antiquity: unsustainable
  • Agriculture: unsustainable
  • Hunter-Gatherer: sustainable?

Most, I claim, are unsustainable, to varying degrees. I’ll expand on why below, but the short version is that all post-agricultural modes set up accumulating ecological decline that would eventually spell game-over. Monotonically downward measures of ecological health cannot be called sustainable, even if it takes millennia to drop to terminal levels. The only one I characterize as potentially sustainable is the last. The question mark is because of megafauna extinctions, being the only species to use fire, and the fact that an ability for symbolic representation and complex speech might be the recipe for a runaway species capable of rapid cultural evolution and technology development out of step with the rest of the community of life, and therefore maladapted to long-term co-existence in ecological relationship. If it looks like we’re winning the “battle against nature” right now, that’s actually what losing looks like.

So, the question mark in the last item reflects the fact that we still do not (and cannot) know whether Homo sapiens is an evolutionary step too far, bound for self-termination (although sadly not confined to our species as we take many down with us). I will operate under the assumption that we are not evolutionarily doomed, for two reasons. First, if we’re destined to fail as a species, then our goose is cooked, and nothing I suggest will change the animal we are. Second, we know of cultures that have deliberately suppressed overreach, valuing a humble role in the broader community of life. We therefore have models for how things can work, at least for the intermediate term.

Before going on to explain the other entries, I should get in front of one potential objection. I am not claiming that a hunter-gatherer lifestyle is the only way for humans to live sustainably on the planet: just that it’s the only one we’ve tried yet that is potentially sustainable. Everything that has branched off that path so far appears to be a dead end. Might there be new paths as yet unexplored—perhaps merging the knowledge we’ve acquired with time-tested wisdom? Surely, it would seem. But don’t ask me to describe ways in which no human has yet lived: I can’t.

It might be obvious that the present way of living is grossly unsustainable (thus the BOLD CAPS above). As a hint, it is likely that any mode that contains 8 billion humans—so that humans and associated domesticated animals constitute 96% of all mammal mass on the planet—will be unsustainable for any relevant length of time.

I “did the math” in an earlier post showing that human population growth in all but the hunter-gatherer mode was on track to reach 8 billion in contextually short order. The upshot was that the four unsustainable modes would have reached 8 billion (assuming growth rates characteristic of those times held steady) by the years 2020, 2300, 3800, and 8800 in the order listed above. Keep in mind that 7,000 years from now is still a flash compared to contextually relevant timescales.

Okay, but it’s clear enough that continued growth at any rate is a prescription for trouble, as this blog has quantified six ways to Sunday. In that case, what if we just went back to 1990 levels and held steady there? Life wasn’t so bad then, and we weren’t nearly as unsustainable as today. No? Maybe the 1950s, then—a swell time. Not buying it? 1900? Really? Okay, so then before fossil fuels, like 1800, when global population was just 1 billion. Surely cutting back human presence by an order-of-magnitude and living more simply would set us to rights. Even that level of “sacrifice” would be asking an awful lot of people!

Let’s address reasons why I characterize earlier modes as being unsustainable, working backwards in time.

Modern Living

We start by assessing “20th century” lifestyles, the definition of which could be loosened to go back to mid 19th century in accommodation of the Industrial Revolution, and up through the present. Ours has been an age defined by fossil fuels.

First, any mode dependent on fossil fuels is right out, in the sustainable contest. Setting aside the CO2 emissions issue, any system based on a non-renewable substance is unsustainable—killing many fantasies. That certainly rules out 20th century living, as executed. Because so many elements of modern lifestyles are completely in the context of fossil fuels—how we feed people, how we manufacture cities and roads and consumer goods, how we extract materials from far-flung places and move them around the world, how we impose hegemony and “peace” through military might—we can’t surgically remove fossil fuels and pretend that the system would look anything like what actually developed. Once a cancer is fully metastasized—integrated throughout the body—it is impossible to separate cancer and body, or to kill the cancer while keeping the body alive. Nor can the body continue to live that way, making the metaphor more apt than I originally intended. Yeah: we’ve got Stage-IV Modernity on our hands. Most unfortunate. Time for Hospice.

Many would react by saying: “Okay, but don’t be daft: what about performing all those tasks by alternative means like solar, wind, hydro, nuclear, etc.?” Several things come to mind at once (head-exploding moment). First, what we do with copious energy—in any form—has been devastating to the community of life. Swapping the gas chainsaw for an electric one is pointless if its application is sawing off the branch on which we and many other beings stand. Second, we have not demonstrated the ability to do these things without fossil fuels at scale. Electricity is just not the same as combustion, or as chemical feedstock (thinking fertilizer, here). High-temperature heat for processing mined ores and for manufacturing, energy-dense storage for long-haul transport and global military operations (all part of our present mode) may not be possible in 20th-century style without fossil fuels. Third, no energy technology is free of non-renewable materials (mined), and in fact the “renewables” require more mined materials than fossil fuels do to produce electricity from such a diffuse source. It becomes very hard to make a convincing case for continued renewable energy technology over timescales that matter. The advocates don’t even try to make this case or address how we we would somehow stop using energy to execute ecological atrocities—which to me indicates a core part of our problem: the focus is far too narrow. Lots of “punting” going on, hoping for the best (more “living large”).

The main point is that the rapid declines in ecological health over the last few centuries (see hockey sticks and cliff edge posts) are not due to fossil fuels either being finite or emitting CO2, but because that’s what abundant energy does in the hands of a human supremacist culture. I’d say you can’t have 20th-century life without a heck of a lot of energy, and without a heck of a lot of collateral damage in a completely unsustainable way. Any system that strives to maintain billions of people at industrial-scale energy will continue to wreck the community of life and therefore self-terminate by its own “success.”

Rewind to 1800

So, what about life in 1800? I’ll focus on the European mode of living (essentially the same as settlers in America): high culture, global trade, science. I’ll ignore the inroads that fossil fuels were already making, which indeed were beginning to transform some aspects of life by then.

A main caution concerns global trade. Engaging in global trade might just mean you’ve exceeded your local sustainable capacity. Sure, I understand that it doesn’t have to be this way, because the world is not homogeneous. Trade allows redistribution so that everyone might get what they want or need, in principle, with plenty to go around. It’s just that it seldom actually works according to such an attractive theory, historically, and the “civilized” world has never operated in balanced steady-state trade without net depletion and degradation of ecological health.

Rather, trade has generally been between conducted between “unequals.” Here, I will take the voice of the more powerful (“advanced”) side. “I’d like that stuff you have and that we no longer do (ahem; never mind why). It’s lucky for both of us, because you don’t (yet) have a need for it, or recognize it as useful, you see. By the time you do, in a few centuries perhaps, we’ll already have taken all of it. Besides, you’re not able to defend the resource from our appropriating it. But rather than have this get all nasty—keeping in mind that you would make a rather cute colony—we’ll give you some shiny coins that you can spend on something real nice for yourself, according to your primitive notions.”

In other words, trade tends to be exploitative (surprise!) and is closely connected to colonization—which often cleverly means not having to pay uncouth locals for the loot. Poorer countries are not market-forcing America to chop its forests and pollute its air and water: it works the other way around.

One place local unsustainable excess shows up that is subsequently “fixed” by trade is in the denuding of the British Isles as timber demand soared. Naval ships (inseparable from trade concerns) placed a tremendous demand on timber, so that by 1800 Britain was importing large amounts of wood from distant shores. But ships alone did not rid the isles of their forests: plenty of other demands were swelling simultaneously. By 1900, forest cover had shrunk to 5%. Whatever diverse demands for wood existed at the time, they were too great to support.

The essential point is that if the whole world lived like Europeans of 1800, even at just 1 billion people total, the world’s resources would likely soon be stripped clean. Again, imports are a warning sign of unsustainable imbalance.

Since Earth does not import resources, we can look at global metrics of forest cover and other attributes of ecological health to assess if things are sustainable. Downward trends have been the rule for many centuries: the opposite of sustainable. It has been a very long time since human activity has not resulted in aggregate global decline of ecological health.

Aside on Extinctions

As a measure of ecological decline, extinctions are swelling in number, and have been for quite a while. For a depressing time, see the Wikipedia page enumerating a chronological list of over 800 extinctions. While this surely is not a complete list (strong vertebrate bias, for instance), the simple exercise of counting the entries is revealing: it’s more than just the Dodo in 1688. Tables that initially are broken into millennia become just decade-long tables near the end, and actually have more entries than their millennial counterparts! I can’t vouch for uniform completeness across the span, but the planet has been crawling with naturalists for the last few hundred years, so I tend to trust the recent numbers. All the same, I am impressed with how much we do know about prehistoric extinctions from the various pieces of forensic evidence left behind. The table below captures the trend of extinctions per century across various time spans (in years).

−10000 −2000 1.5
−2000 0 2.5
0 1000 5
1000 1600 10
1600 1800 35
1800 1900 130
1900 1950 275
1950 1990 385

After 1990, the numbers begin to taper, presumably because many extinctions become official only after a conclusive delay. All the numbers are above the long-term background rate, but swell by a couple orders-of-magnitude as modernity revs up. Only three of the causes offered in the Wikipedia table are potentially attributed to modern climate change. The rest stem from the usual suspect list of deforestation, habitat loss/destruction, hunting, invasive introductions (by humans) and related diseases. In short: what we do with energy.  No: 1800 was not sustainable, even with a small fraction of the globe living like Europeans. This leaves us with little confidence that even a billion people could live sustainably in that way.

Fall of Rome

What about antiquity? Could the whole world live like the Romans, or the Greeks? Well, even they couldn’t manage to do so, even while exploiting surrounding areas that lived more simply. The model does not scale if everyone tries to do the same, at the same time, with no externally exploitable people/lands. Sumerians, Babylonians, and Mayans were likewise unable to hold it together, among others. Many scholarly works have expounded on the factors contributing to these failures. While it is not a one-size-fits-all story, a common thread is exceeding local carrying capacity by engaging in short-term inheritance spending of ecological wealth (soils, forests, biodiversity), accumulated over much longer tracts of time. It’s a cunning trick, while it lasts: so tempting!

But the people of antiquity didn’t have technology and solar panels, one might object. Yeah, and if they did, how would they keep the materials treadmill going? We’re still dealing with finite resources and inescapable degradation of existing materials. Plus, one could argue that the destruction would have been faster if assisted by additional power input: all the better to shred the local web of life. I don’t know how exactly I allowed modern technology to creep into antiquity.  Nice try. In general, unless any extra energy (beyond the ecological distribution) is used for ecological restoration, it’s generally going to result in its destruction.

Pre-civilization Agriculturalists

Okay, if we must keep backing up, why couldn’t the agricultural ways predating city-states have been carried out sustainably and indefinitely, if population growth is somehow held at bay?

Fertile lands do not remain so forever. Annual agricultural practices accumulate a toll. The soil is effectively “mined” of mineral content that if not fully replenished (all poop back on the field) will result in eventual cessation of productivity. Irrigation tends to slowly concentrate salt, eventually poisoning the ground. Plowing disturbs the integrity of soils, contributing to wind and water erosion. Grazing by domestic animals also leads to similar fates. Eliminating all but the desired plants (“weeds,” “pests”) impoverishes the soil in terms of microbial, fungal, and invertebrate diversity. Without natural cycles replenishing lost nutrients—like floodplain deposition of new soils, which happens only in a few special places, lately not tolerated and prevented by levees—agricultural exploitation is a one-way ride. The ride can indeed persist for many generations of humans, but is still short-term compared to timescales that matter.

The past is littered with stories of places once agriculturally productive that are now desert or scrub. Over the thousands of years that agriculture was practiced prior to recorded history, archeological evidence points to abandoned efforts that only lasted a few hundred years before the land could no longer support the experiment.

What matters, here, is that the agricultural method is not vetted by multi-level selection (evolution) to be a viable way of living in stable relationship with the community of life. Besides the fact that agriculture tends to build surplus, which fuels population growth, hierarchy, armies, etc. (see post on the river metaphor), and therefore sets up an unsustainable growth train, it appears to fail even without those elaborations just based on what the land can support, long term, without being monotonically degraded by the effort.

Forests and other ecological arrangements can indeed self-sustain “indefinitely,” but only because they self-select a diverse complement of organisms that perform all the necessary functions to keep the cycle going—in everybody’s mutual interest. It’s not “survival of the fittest,” but survival of the collective that matters. Agriculture is an artificial approach that might try to mimic some vital ecological functions, but incompetently and without the benefit of many millions of years of self-tuning. It can appear to work for a time, and get a major extension by being propped up on fossil-fueled fertilizer and labor—further distorting our narrow perspectives. Given the brevity of the experiment, we certainly cannot proclaim the practice to be sustainable, especially when evidence points to the contrary.

Snap Out of It!

I am not calling for an immediate cessation of agriculture. I depend on it as well. What I am doing is calling into question baseline assumptions—uncomfortable as that might be. In laying the tracks for future generations, we might encourage exploration into different modes of living, with an eye toward long term sustainability.

I can’t stop myself from returning to the metaphor of cutting off the branch we stand on. In light of this post, we started the project 10,000 years ago using a crude stone edge that later became an iron axe—beginning to make some slow progress. The enlightenment brought a toothed steel saw: much more effective. The fossil fuel revolution introduced the chainsaw. Luckily the branch is large and resilient, capable of much abuse. But just as we’re nearing completion of the cut, the fossil fuel inputs and outputs are becoming problematic (smelly fumes). Shall we then switch to a solar-charged electric chainsaw to finish the job? I’d rather we pause to ask what exactly it is we’re doing, using a broad lens in terms of time and ecology. Safety first!

Meanwhile, can we please stop indulging fantasy engineering babble about a high tech future that either never will come or if it does just proves to be one more bad idea that prolongs (and worsens) the eventual fall? The ecological nosedive (sixth mass extinction) continues to steepen, making the chances of recovery slimmer year by year. I don’t want to hear about energy on Mars or grid-scale pumped storage that drowns every dam-able bowl on the terrain. It’s embarrassing. Enough destruction. The goals are all wrong.  Let’s begin the healing, by first falling out of love with (abusive) modernity, and thinking about what matters most in life. Hint: don’t stop at humans, as that spells a dead end for humans as well.

Tom Murphy

Tom Murphy is a professor of physics at the University of California, San Diego. An amateur astronomer in high school, physics major at Georgia Tech, and PhD student in physics at Caltech, Murphy has spent decades reveling in the study of astrophysics. He currently leads a project to test General Relativity by bouncing laser pulses off of the reflectors left on the Moon by the Apollo astronauts, achieving one-millimeter range precision. Murphy’s keen interest in energy topics began with his teaching a course on energy and the environment for non-science majors at UCSD. Motivated by the unprecedented challenges we face, he has applied his instrumentation skills to exploring alternative energy and associated measurement schemes. Following his natural instincts to educate, Murphy is eager to get people thinking about the quantitatively convincing case that our pursuit of an ever-bigger scale of life faces gigantic challenges and carries significant risks. Note from Tom: To learn more about my personal perspective and whether you should dismiss some of my views as alarmist, read my Chicken Little page.