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Agrifood Systems, Chokepoint Warfare, Civilizational Metabolism, Climate And Conflict, Collapse Discourse, Energy And Famine, Energy Geopolitics, Fertilizer Shortage, Global Food Security, Imperial Retrenchment, Industrial Civilization, Iran War, Just‑In‑Time Fragility, Maritime Insurance Crisis, Oil Market Shock, Petrostate Politics, Risk Society, Strait Of Hormuz, Supply Chain Fragility, Systemic Collapse

Peace on a Broken Artery
By now the war in Iran has settled into a grim routine. Tankers inch through militarized sea lanes under the eyes of drones. Jets rise off carriers and desert runways to drop precision ordnance on an already cratered landscape. The Strait of Hormuz, a thin scrawl of water between rock and sand, has become a fault line of global anxiety. Officials in Washington and Brussels still describe it as a problem of “regional stability,” “energy security,” and “deterring aggression.” If you read beyond the podiums and into the fine print of the economic and risk reports, another story emerges. The people who administer this order have started to describe, in careful bullet points and euphemisms, the early stages of its breakdown. They simply refuse to say the word collapse.
In late March, a new line floated out of the White House and friendly media: President Trump is reportedly willing to end the military campaign against Iran even if the Strait of Hormuz remains largely closed.
On paper, that sounds like an exit. In practice, it is an admission that whatever this war’s end state, one of the main fossil‑fuel arteries of industrial civilization will remain damaged. Whether the fighting stops next month or drags on, Hormuz is not going back to what it was in January. Nor, if the architects of this adventure have their way, is Iran.
The question is not whether dismantling or maiming the Iranian state would create chaos along that artery. It is how much of that chaos would be exported into the food and fuel systems that keep billions of people alive.
A Chokepoint as a Systems Diagram
In the public imagination, Hormuz has long been an oil chokepoint: a narrow passage for roughly a fifth of seaborne crude and a significant share of LNG. In practice, it is also a fertilizer chokepoint, a petrochemical chokepoint, and a shipping chokepoint. The Iran war has made that explicit. Iranian missiles, drones, and mines, combined with U.S. and Israeli strikes and a cascading wave of insurance withdrawals, have exposed the strait as a single, brittle joint in a civilization‑scale supply chain. UN agencies now estimate that roughly 35 percent of global crude and nearly a third of fertilizer trade normally flows through Hormuz, and that tanker traffic has fallen by more than 90 percent since the war began.
Since late February, tanker and bulk traffic through Hormuz has collapsed from the usual torrent of oil, gas, and fertilizer that props up half the planet’s metabolism to almost nothing. The IRGC has warned vessels away and carried out at least twenty‑one attacks on merchant ships. War‑risk insurance has been pulled. Crews have invoked their right to refuse to transit. The strait is technically open but effectively closed to normal commerce. And if this campaign succeeds in bombing Iran’s state capacity into rubble, it does not reopen the artery; it hands the coastline to militias and jihadist franchises for whom intermittent hijackings, mining scares, and rocket fire on tankers are tools of extortion, recruitment, and proxy warfare. For them, keeping Hormuz unreliable is not a problem to be solved but a tactic to be used.
The first thing that moves is a price chart on a screen. Futures spike, analysts talk about volatility, and traders front‑run the headlines. In the real world, the shock lands in treasuries and streets. Import‑dependent countries watch their fuel and food bills jump at the same time. Hard currency drains away. Subsidy regimes that kept bread and diesel politically quiet start to unravel. Cabinets fall, parliaments are dissolved, opposition parties and street movements suddenly have an opening. A few months of disrupted nitrogen and diesel have, in the past, helped push vulnerable governments closer to default, revolt, or both. Those shocks don’t stay local. They ricochet through debt markets, migration routes, and security alliances—a handful of missiles and insurance letters in the Gulf rewriting the political order thousands of miles from those troubled waters, after major marine insurers simply pulled war‑risk cover and left hundreds of vessels stranded at anchor.
None of this is speculative. The UN Food and Agriculture Organization calls this ‘a systematic shock affecting food systems globally,’ warning that farmers face a ‘double choke’ of fertilizer and fuel prices rather than a passing scare. Its chief economist says global markets can probably absorb the shock for ‘about two weeks’ before risks of broader food insecurity rise sharply, and that if the conflict and the closure of Hormuz last three to six months, the shocks will be ‘global and harder to manage.’ A UN‑linked analysis flatly states that if the war does not end quickly, ‘global markets could collapse from the high demands for oil and crops,’ as unrelenting need for these inputs collides with war‑constrained supply and pushes the system past what it can absorb.
In their world, the Iran war is no longer a “geopolitical flare‑up.” It is a “global agrifood systems” crisis layered on top of an energy crisis. Translated into English: the bombs are falling in the Gulf, but the shockwaves are moving along the supply lines that keep cities fed and states solvent.
What is missing is a simple sentence acknowledging what those phrases amount to: behold a vast global civilization built across a set of concentrated, brittle lifelines which we are now actively destroying.
Ending the War Without Fixing the Artery
Into this situation comes the new talking point from Washington: that reopening Hormuz is no longer a prerequisite for ending the war. Trump has reportedly told aides he is prepared to conclude the campaign even if the strait remains “predominantly obstructed.” He does not want a drawn‑out effort to clear mines, neutralize coastal batteries, and escort a critical mass of tankers and fertilizer carriers through hostile waters. He wants a short war, a weakened Iran, and an exit.
The theory seems to be that if U.S. and Israeli forces smash enough of Iran’s missile launchers and patrol boats, Tehran will eventually choose to reopen the strait for its own economic reasons or under pressure from other powers. If not, the job of prying it open can be handed off to regional navies and insurance consortia later.
This is what “victory” looks like in the airpower age: decapitate some units, degrade some arsenals, then declare the strategic problem solved while the structural damage remains. In this case, the structural damage is not confined to runways and radar sites. It is a shift in how Hormuz works as a global artery.
Physically, the war leaves behind unexploded ordnance, damaged infrastructure, and an elevated baseline risk of attack. Politically, it normalizes the use of the strait as a weapon. Iran has now demonstrated that it can close or severely restrict traffic when under attack. The U.S. has demonstrated that it will tolerate weeks of closure for the sake of a punitive air campaign. Every future crisis will be negotiated in the shadow of that precedent.
Financially, it bakes in higher war‑risk premia, higher insurance costs, and a secular push to reroute or diversify trade—pipelines through Saudi Arabia and the UAE, more LNG out of the U.S. Gulf, more storage and stockpiling in rich countries. Some of that diversification will succeed. Much of it will not arrive in time for the farmers currently deciding whether they can afford another season of ammonium nitrate.
Ending the war without fixing the artery does not restore the old normal. It crystallizes a new one: a Gulf that is more mined, more militarized, and more obviously central to food as well as fuel. A chokepoint that has been shown to be closable at will, but not reliably reopenable by force within an acceptable timeframe.
From Hostile State to Ungoverned Corridor
War planners like to imagine that the alternative to a hostile regime is a compliant one. In practice, the record of the last twenty years suggests something else: the alternative to an intact adversarial state is often a fractured, semi‑ungoverned space that bleeds instability into the surrounding region.
Dismantling or maiming the Iranian state would not produce a peaceful, demilitarized Gulf. It would turn the country that sits astride one of the world’s key arteries into a patchwork of factions, militias, and proxies with access to missiles, drones, and coastal systems along hundreds of miles of shoreline.
You do not need to believe in a neat “Iraq 2.0” analogy to see the contours. A weakened central government loses its ability to police its own forces and waters. Rival power centers inside Iran—Revolutionary Guard remnants, provincial elites, separatist movements—jockey for control of ports and oil terminals. Outside powers—Saudi Arabia, the UAE, Turkey, Pakistan, Russia—move to back their preferred clients. The IRGC’s current, relatively centralized control over Hormuz is replaced by something more chaotic: multiple actors with both the capability and the incentive to harass shipping.
From the standpoint of global food and fuel flows, this is worse than a hostile but coherent state. A disciplined adversary can threaten closure or limited disruption as a bargaining chip, but it also has a strong interest in collecting transit fees, exporting its own commodities, and avoiding complete economic suicide. A fragmented security environment produces something else: piracy, sporadic attacks, deniable incidents, and a constant background risk that any given convoy will be targeted by someone trying to send a message, settle a score, or shake down a client state.
Think of it as Somalia‑plus‑Strait‑of‑Malacca, sitting on the fertilizer pipe. The fantasy that you can bomb your way to a safer Gulf by “dismantling” the current Iranian state rests on the assumption that the post‑war order will be more predictable than the one it replaces. Nothing in the region’s history, or in recent U.S. expeditionary adventures, supports that belief.
Food, Fertilizer, and the Permanent Premium on Survival
The global food system was already fragile before the first missile flew. Climate change is quietly dialing down yields, even when farmers adapt, with new modeling showing significant declines in major staples under both optimistic and business‑as‑usual scenarios. Supply chains optimized for just‑in‑time efficiency, not resilience, have shown how easily they jam under pandemics and cyberattacks. Hundreds of millions have been shoved back into hunger in the last decade as “overlapping crises” hit systems that had been strip‑mined of slack.
Layer a permanently more dangerous Hormuz on top of this and you change the price of survival. Not just in dollars, but in options.
A Gulf where fertilizer shipments are always a little at risk, where insurance is always a little more expensive, where warships are always a little closer to collision, is a Gulf that quietly raises the floor on global food prices. Poor countries that import both calories and energy see a larger share of their budgets eaten by basic inputs. Governments already inching along the edge of default find that each new drought, each new price spike, each new conflict pushes them closer to the brink.
The FAO’s warning that global markets could “collapse” from unmet demand for oil and crops if the war drags on is not about one bad season. It is about how close the system already is to the edge. A sustained premium on fertilizer and diesel does not just show up in supermarket price tags. It shows up in the choices farmers make about whether to plant at all, and in the choices governments make about whether to subsidize bread or pay bondholders.
From the standpoint of someone who still sees full aisles and stable prices, this may sound remote. But the Gulf remains one of the central organs of the global economy; weakening it badly enough makes the entire system weaker. The same is true of the glaciers that feed Asia’s rivers, the jet streams that steer storms, the topsoil that anchors prairie roots. We are eroding multiple load‑bearing structures at once. The fact that you can still buy strawberries in January does not mean the scaffolding behind them is sound. It means the remaining slack is being spent to preserve the appearance of normality.
Ending the Iran war while leaving Hormuz damaged simply moves that erosion into a new phase. The artery does not have to be completely severed to change the metabolism of the system it feeds. It only has to be scarred enough that each heartbeat is weaker than the last.
Ignoring the Rot
Insisting that collapse is either a Hollywood event or a forbidden topic has been a useful way of keeping it off polite agendas. It is harder to sustain that taboo when the underlying processes are being described, in other words, by the system’s own custodians.
Central banks warn that repeated “supply shocks” could unanchor inflation expectations and constrain their tools. Humanitarian agencies talk about “permanent emergency operations” in regions hit by overlapping food, conflict, and climate crises. UN bodies now say, in plain language, that a few more months of war in the Gulf could push tens of millions into acute hunger and set global agrifood markets on a path toward breakdown. Security analysts frame the Iran war as a “test case” for how long global shipping and insurance can function under sustained missile and drone harassment. Even establishment summaries now warn that prolonged disruption could drive oil toward its previous record, force importing states into rationing, and in the words of one Gulf minister risk “collapse of world economies” if force‑majeure declarations spread.
None of these admissions need the word collapse to be true. But their accumulation makes the refusal to use it look less like caution and more like superstition. As long as we do not say the word, perhaps the thing it describes will not happen.
What does it mean, in that context, to declare peace while leaving a main fossil‑food artery damaged? It means telling ourselves the lie that the crisis was the airstrikes and the headlines, not the long tail of higher prices, thinner margins, and brittle systems they leave behind. It means treating the war as over when the kinetic phase slows, even as the structural consequences continue to compound.
We can, for a while, pretend that this is a return to normal: oil back down a few dollars, markets rallying on talk of a deal, commentators praising “restored deterrence.” We can avert our eyes from the farmers deciding which fields to leave fallow, the governments weighing bread subsidies against debt payments, the families in importing countries watching staple prices climb and never quite come back down.
Or we can call it what it is: another notch in the ratchet of a civilization running a planetary experiment past its design limits. A war that ends on paper but lives on in the arteries it scars.
The choice we face is not between ending the Iran war and preserving the world as it was before. That world is already gone. The choice is between acknowledging that fact and organizing around it, or continuing to accept illusions of victory that leave the underlying systems more fragile each time.
There will be more proposals in the coming weeks: Pakistan‑China peace plans, U.S.‑brokered “de‑escalation frameworks,” legalistic arguments about who should “take over” the job of reopening Hormuz. None of them grapple with the deeper question your stomach already understands better than any communique: what happens to a global civilization when it refuses to see the growing rot beneath its feet?
hey Mike, I saw you made a post on future civilisations, and im glad I made you think of them!
Although, I still think i might find some things to change your mind.
First of all, I’d like to address timeframe. Yes, we might be diminished for a thousand years. But (barring an asteroid, chemical crisis, biological crisis, nuclear war) etc, we’ll survive much longer. What about ten millennia down the line? A hundred millennia?
An MIT analysis of zero‑emissions trajectories, for example, finds that if emissions stopped, global temperature would typically stop rising within a few decades, but stay elevated for centuries, with maybe half a degree of cooling over 250–300 years in ambitious cases. The direction reverses; the slope is shallow. For any society trying to re‑aggregate in 2200 or 2500, the baseline isn’t “back to Holocene normal,” it’s “still significantly warmer and hydrologically weirder than the climate that fed Rome and Han.”
Yes, and half a degree is (assuming 2.5c of warming) 20% of the warming gone. I know, long tail etc (i grieve about this regularly), but that’s still notable.
Ecosystem services beyond raw wood: Old-growth provides more stable game populations, better soil/water regulation, and resilience to drought/pests in some cases. Secondary forests recover biomass and basic productivity faster but often lag in full structural complexity and certain biodiversity components that indirectly support long-term human use (e.g., pollinators, pest control).
Agree. Except again, turning to history, Rome and China *depended 90% on managed secondary growth forests*. That counts for something. The only old-growth logs they used were for monuments or massive structures.
But biomass is only functionally renewable for complex societies if three conditions hold at once: Harvest stays at or below ecological regrowth rates. Those same landscapes don’t also have to feed a similarly large human population. You solve the power‑density problem: biomass is low‑density and scattered; running industrial‑scale infrastructure on it takes a lot of land, logistics, and labor.
I argued from the outset against a rerun of industrial-scale agriculture. And i think you had the impression that i was arguing for a steady state rome; i was not. I agree, harvest must stay below regrowth rates for a society to keep chugging. But i was arguing for a repeat of smaller overshoot cycles. EG Rome collapsed (as you also noted), huge reforestation happened. THAT is what i argue for
When you look at modern assessments of sustainable bioenergy potential, even in well‑governed, data‑rich countries, a pattern emerges. Under optimistic assumptions about yields, technology, and governance, sustainably harvested biomass typically covers only a fraction of total energy demand—on the order of a quarter to perhaps two‑fifths—nothing like the fossil‑era peak.
Yes, agree. Again, two things though: That’s total demand in the MODERN ERA, where we use six times as much energy per capita with 20 times the population. So divide that number by 120.
Collapse advocates sometimes sketch a “stair‑step” future: collapse, abandonment and reforestation, then a new biomass‑powered civilization rising on the regrown energy base. There’s something right in that image. Abandoned land does green; secondary forest growth in many places really can offset a non‑trivial share of deforestation‑driven emissions. But it’s one thing to use that regrowth as a carbon sink. It’s another to run a civilization on it. Fragmented post‑collapse societies, even with centuries of regrowth behind them, are unlikely to squeeze dramatically more usable energy out of the biosphere than modern studies think possible without repeating the same mine‑the‑land pattern that hammered Rome’s hinterlands. The staircase is real, but each future step up is likely to be smaller than the one before, because the overall resource envelope keeps shrinking.
I don’t think that’s what i argued, or at least i think thats an oversimplification. Yes, they will be unlikely to squeeze dramtically more usable energy out. But what if they only need 1/120th of the energy we use now? In that case, even a 50% deficit is a hit we can take. I agree the mine-the-land pattern will indeed happen again, which leads to collapse. What happened to the forests of europe after Rome collapsed? And the fact remains that even if we do extract, we simply CANNOT do the damage we are doing right now without fossil fuels. Earth’s recovery simply outpaces us. No chainsaws,excavators…. and not enough people.
Lose ice sheets, rearrange ocean circulation, push biomes poleward, acidify oceans, extinguish keystone species, and you don’t walk back to the 8,000–1800 CE climate by waiting 200–500 years. The IPCC’s Special Report on the Ocean and Cryosphere is blunt about this: many ocean and cryosphere changes – ice‑sheet and glacier mass loss, ocean warming and acidification, permafrost thaw – are effectively irreversible on timescales relevant to human societies, even if warming stops. Ice sheets would take centuries to millennia to regrow; sea‑level rise and deep‑ocean warming keep intensifying long after emissions cease.
Agree. But then you have to compare farmland elevation to sea level rise, and factor that against climate change. For example, greenlands full melt is supposed to take 10000 years, and by that time a lot more of the temperature anomaly is gone. according to this paper
https://bg.copernicus.org/articles/22/2767/2025/#section2
we’re back to 1.5c!
Even if global temperature nudges downward, the pattern of rainfall, monsoons, river regimes, and extremes is unlikely to simply revert. For staple crops, that pattern matters as much as the global mean. AR6’s water‑cycle chapter shows with high confidence that warming intensifies both very wet and very dry events and shifts where heavy rain, drought, and runoff extremes occur, with strong regional changes in monsoon behavior and seasonal flows rather than a simple, uniform scaling with global temperature. Those changes in variability and extremes track directly into food production and staple crops.
I agree, but heterogenity is very important. Did you know that droughts are projected to decrease in many parts of china?
https://www.nature.com/articles/s41612-024-00578-5
On the biosphere side, extinction is forever. The exact web of species interactions, soil microbiomes, and cheap, easily accessible mineral and fossil resources that early empires leaned on will not be recreated just by letting ecosystems grow back on their own. The IPBES Global Assessment underscores that extinction and many forms of biodiversity loss are irreversible on human timescales, and that ecosystems are being reorganized into “novel” assemblages rather than returning to historical baselines, even where biomass regrows.
Agree, sadly, except most microbiomes havent left, and since when did we use fossils in rome? As for ores: cities exist. the metal hasnt gone anywhere, and they don’t even need to mine it this time. so:
On the geochemical side, work on “peak minerals” argues that we are progressively exhausting high‑grade, easily accessible mineral deposits – iron, copper, phosphates among them – forcing a shift to lower‑grade ores that require much more energy, water, and capital to exploit.
In the future, cities BECOME mines. We don’t need phosphates for fertiliser in rome…
I could give an essay where i calculated how long city metals could last for, but this comment is long enough already.
So , what do you think?
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No replies yet but I’ll offer one. Whereas many of the dynamics you describe can be observed and analyzed (only partially), typically by individuals or small groups, once humans aggregate into societies, the picture becomes illegible while behaviors remain irrational. Nature evolved a giant system of interlocking systems that shares with human systems one major dynamic: rise and fall. The notion that humans can design and operate a better system without all the unnecessary early death is a die-hard Utopian dream. Many have labored under its allure; none have advanced human flourishing appreciably. Instead, human institutions muddle through. By now they have probably outlived most of their usefulness and may well have entered a final phase of self-destruction.
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I’m glad someone brought this in, because it speaks to a different discomfort that sits behind both my essay and the sense that we can’t really steer these systems, and that trying to design a “better” one is hubris.
A few thoughts in response:
I agree that human systems are partly illegible to themselves. That’s not just cynicism; it’s basically what complex systems theory, James Scott, etc., have been telling us: plans collide with emergent behavior, feedbacks, and local knowledge.
I also share the suspicion of utopian blueprints. If “the next civilization” means some rationally planned, death‑free, perfectly steady‑state global order, count me out. That’s not how ecologies, brains, or cultures work.
Where I diverge is on the jump from “illegible, messy, rise‑and‑fall” to “institutions have outlived their usefulness and are just self‑destructing now.”
Institutions are the way we:
Coordinate responses to shocks (food reserves, public health, disaster relief).
Encode and transmit learning (what didn’t work last time).
Bargain, however clumsily, over who bears which costs.
They’re bad at it; they’re often captured; they can be monstrous. But they are also the only tools we have for slightly bending trajectories away from worst‑case outcomes. The FAO warnings I cite, the climate models, the IPBES reports—all of that is institutional output.
The point of my essay is not “we can design a clean reset” but “we can at least tell the truth about the direction of travel and stop mistaking paper victories for structural repair.” That’s not utopianism, it’s the bare minimum of risk management.
Yes, rise and fall is baked into complex adaptive systems.
No, that doesn’t mean nothing we do matters or that all institutional action is just noise before the crash. There are many different ways to fall, and some leave more room for future beings than others.
My essay is arguing for honest diagnosis within institutions that currently specialize in euphemism. That’s not a plan for a perfect system; it’s an attempt to stop our current ones from turning ignorance into an accelerant.
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I was replying to the comment above more than the blog post.
Thus far, industrial civilization has operated on nature rather than within it, based in part on ideological dominion over nature. That got humanity a long way (a few millennia) but we are now arguably past our zenith in terms of rise and fall. Human institutions and the enclosing global civilization are both running down. For a long time now, my stated ambition has been to ameliorate suffering (insofar as that can be accomplished) as collapse picks up speed and severity. No small task. Others want to redesign human dominion over nature to be more what? rational? effective? balanced? My point is that aggregate human psychology disallows engineering a supersystem even remotely equivalent to what nature has evolved. Humans only tinker around the edges.
Agreed that well-organized and -run institutions are probably the best way for complex societies to self-organize and operate. However, it’s a little like Churchill’s quip: “Democracy is the worst form of government, except for all the others.” Also, once institutions become sclerotic, corrupted, and captured, they are no match for hypercomplexity.
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I think we’re very close on diagnosis and differ mainly on what follows from it. I agree that industrial civilization has mostly operated on nature rather than within it, and that we’re never going to “engineer” a supersystem on a par with what evolution has built. We’re tinkering primates in a hypercomplex ecology, not gods. I also share your suspicion of utopian blueprints: if “the next civilization” means a rationally planned, death‑free, perfectly steady‑state global order, I’m out. That’s not how ecologies, brains, or cultures behave.
Where I hesitate is the step from “we can’t design a nature‑equivalent supersystem” to “institutions are basically used‑up and no match for hypercomplexity, so all that’s left is palliative care.” Institutions are crude, captured, often monstrous, but they’re still how we coordinate responses to shocks, encode and transmit learning about what went wrong last time, and bargain—badly—over who carries which losses. They absolutely cannot make the whole system stable or controllable; that bar is impossible. But that doesn’t make them irrelevant.
On the narrower question of whether they can bend specific damage trajectories, we do have at least one very consequential example: the Montreal Protocol. We were on track for long‑term, severe ozone depletion and a century of elevated UV; instead, a stack of fallible institutions managed to phase out most ozone‑depleting chemicals and put that system on a recovery path, likely avoiding catastrophic ecological and health impacts and additional warming. That didn’t “save civilization,” but it did move one arc of harm away from a much worse future. That’s roughly the level of steering I have in mind. “No mastery of hypercomplexity” doesn’t have to mean “nothing we do at the institutional level matters.” It may not change the broad arc, but it still shapes the texture of the descent and that’s where our remaining agency actually lives.
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I agree that we’re pretty close in our assessments. The main differences may well be just tone. Unlike most sites, when commented at your blog, I don’t have to fill in knowledge gaps or sugarcoat, which probably gives the impression of hopelessness. If we agree on the basic trajectory, leaping over collapse to the next civilization (skipping the population die-off and a century or more of suffering, at least ideologically) comes easy to lots of commentators. However, if I’m stuck at hospice and palliative care for this civilization, that doesn’t mean I’m simply giving up or crawling willingly into the grave. Nor do I recommend that for others. Worthwhile, humane steps can be taken even as they fail to alter the overall downward trajectory. That’s not doing nothing.
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I read you as making three big points:
Over long enough timescales (thousands of years), a lot of the damage attenuates.
History suggests repeated overshoot‑and‑recovery cycles (Rome → regrowth → new civilizations) are possible.
Future societies will be so much smaller and poorer in energy terms that today’s limits and “peak mineral” concerns will look less binding.
I think there’s real truth in all three, and also some important caveats.
On timeframes and “half a degree back”
You’re right that, in a world where we peak around, say, 2.5 °C, shaving off half a degree over a few centuries is not nothing; that’s ~20% of the anomaly. It’s a meaningful easing of the background stress.
But there are three separate clocks running:
The temperature clock (which can drift down slowly).
See IPCC AR6 WG1 and SR1.5 on zero‑emissions pathways and the expectation that global mean temperature stabilizes within a few decades and only slowly cools thereafter.
The ice and ocean clock (which keeps going for centuries to millennia even if temperature plateaus).
See IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), FAQ 1.2. It states:
“Even if global warming were to be halted, it would take centuries or more to halt ice sheet melt and ocean warming.”
The infrastructure and settlement clock (where we’ve already built trillions of dollars of stuff in the wrong places for the climate we’ve created). The PNAS study finds that the value of assets sitting below the 1‑in‑100‑year coastal flood level is projected to reach 17–180 trillion dollars under low emissions (RCP2.6) and 21–210 trillion under high emissions (RCP8.5) by 2100, explicitly counting buildings and infrastructure in low‑elevation coastal zones.
Greenland’s full melt taking on the order of 10,000 years is reassuring in one sense. The problem is that you don’t have to lose the whole sheet for sea‑level rise to be civilizationally nasty. Two or three meters over a few centuries is enough to redraw coastlines, river deltas, and some of the most productive farmland and port infrastructure on Earth. That’s well within “relevant to human societies,” even if the physical system keeps evolving long after. See IPCC AR6 chapter on coastal cities and settlements which states:
“By 2050, more than a billion people located in low-lying C&S will be at risk from coast-specific climate hazards… Between USD 7 and 14 trillion of coastal infrastructure assets will be exposed by 2100… Coastal flood risk will rapidly increase during coming decades, possibly by 2–3 orders of magnitude by 2100 in the absence of effective adaptation… Impacts reach far beyond C&S; for example damage to ports severely compromising global supply chains and maritime trade.”
So yes: far‑future humans are unlikely to be stuck in a perfectly flat 2.5 °C world forever. But the path dependence of what we lock in this century still shapes what’s realistically possible for 2200 or 2500, even if the global mean has relaxed a bit by then.
On Rome, secondary forests, and “we can’t chainsaw the planet again”
You’re absolutely right that Rome and Han were not standing on untouched old‑growth. They were mostly running on managed secondary growth, coppice, and agro‑forestry, and they still managed large urban systems for centuries. That matters.
Two big differences now:
They were burning into a Holocene climate with big remaining ecological buffers; we’re burning into a novel climate with many buffers already eroded. IPBES is explicit that regrowth increasingly produces “novel ecosystems” with altered species mixes, soil conditions, fire regimes. That doesn’t make them unusable, but it makes extrapolations from Roman experience shakier.
Their draw‑down of forests, soils, and ores happened with a much smaller population and fewer tools per capita. You’re right we won’t have 8 billion people with chainsaws next time. But we also won’t be starting from an intact, mineral‑rich planet. We’ve already skimmed a lot of the cream.
On your point that “Earth’s recovery simply outpaces us without fossil fuels”: I agree in rate terms—you can’t bulldoze and burn at modern speed without hydrocarbons. But we shouldn’t undersell how much damage a few tens of millions of people with iron tools, charcoal, and animal traction can do to soils, forests, and watersheds over centuries. We have that record in Europe, China, the Middle East already.
So I’m with you that overshoot cycles continue. I’m less sure that the envelope within which they happen stays generous. The staircase metaphor in the essay was exactly trying to capture your point: collapse → regrowth → new societies, but each rung is likely a bit narrower because of what’s irreversibly altered—climate, species, high‑grade ores, easy nitrogen, etc.
On 1/120th of today’s energy
You’re right: most “sustainable bioenergy potential” papers are benchmarked against current demand, which is insane by historical standards. A world using 1/120th of today’s energy would look utterly different.
But that cut also transforms:
The kind of society you can have (very local, far fewer artifacts, far less information infrastructure).
The toolkit you can maintain (how many metals you can keep circulating, how many complex institutions you can keep functioning).
You’re absolutely correct that “cities become mines” and that a lot of metal is already above ground. That’s a real buffer. The constraints bite when you ask how much energy and social organization it takes to recycle and distribute those metals at scale, alongside food, water, and basic health.
So where I land with your argument is:
Yes, smaller, much more modest civilizations can very likely recur, drawing on secondary forests, city‑scavenged metals, and a somewhat cooled but still altered climate.
Yes, they will overshoot again; yes, some reforestation will follow each crash.
But each loop in that cycle is happening in a world with less forgiving baselines: less biodiversity, more “locked‑in” climate weirdness, more diffuse minerals.
That doesn’t mean “no future civilizations.” It does mean the shape space of what’s possible keeps narrowing.
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