Ecological Collapse is not an Existential Risk

By Tandena Wagner @ 2026-08-13T22:40 (+7)

A lot of environmental groups say that we are destroying the earth, and our short-sightedness will bring the world crashing down around us. At EcoResilience Initiative, we've looked into these claims, and while some of them threaten the richness of the Earth's ecosystems, none of them pose a serious risk to the continuation of human civilization.

The three extinction risks from ecological breakdown are: failure of critical life systems, cascading collapse, or depleting a critical resource needed for our survival.^[1] While it is technically possible for ecological collapse to cause human extinction, it seems essentially to be a non-issue. Yes, if 100% of life is wiped out, we cannot survive. But, we likely don't need 50% and perhaps as much as 90% of Earth's species to survive. Each of these require beyond-extreme circumstances to cause human extinction. (Relatedly: the survival of human civilization is not at risk from climate change.)

We Likely Only Need 100,000 Species to Survive

Critical ecological systems require only a handful of species to operate. Around 1-20 species for each of the fundamental ecosystem services. Meaning ~5,000-100,000 (0.01%-1% of total extant species)^[2] should be more than enough for bare human survival.

 To get a rough global estimate of required biodiversity for ecosystem services, I multiply each species required count from this table by the number of global biomes (85-500) and get ~5,000-100,000 (0.01%-1% of total extant species). Total biomes are somewhere between 85 (at the Formation level, which would be minimizing global species) and like 500 (at the Division level which would be using locally thriving species). Totaling that up comes out to somewhere around 7,480 (0.086% out of all extant species) and 81,500 species (0.94%) to support global ecosystem services.

Flaws with this estimate: There are unlisted ecosystem services. I’m overcounting since biomes like “ephemeral salt lakes,” “ground water” and “mud plains” would never provide all ecosystem services. Some species could fulfill multiple ecosystem services. Some species could fulfill multiple biomes. I’m undercounting because supporting ecosystem services would be needed.

I think this estimate is really low for global ecosystem service production, but more than required for a handful of humans to survive.

The other 99% of species could go extinct and critical systems for our survival would still function in places around the globe. That’s thousands of years away at current projected extinction rates.

The real concern would be if some ecosystem services are only supported by a few non-redundant species, and those specific species went extinct. A good example of this is nitrogen production: only ~20,000 plant species produce biologically active nitrogen. But plants are just the hosts for nitrogen-fixing bacteria. Many nitrogen-fixing bacteria are free living and these bacteria are abundant and widespread.^[3] Besides, we mechanically produce our nitrogen fertilizer via the Haber–Bosch process anyway.

Resource Depletion is Thousands of Years Away

Resource depletion is similarly thousands of years away and unlikely to cause human extinction.

To examine an oft-raised example: topsoil loss is claimed as declining rapidly and irreplaceable on human timescales. But we don’t need to return to natural levels of soil organic carbon. Topsoil is not necessary for modern agriculture. We can simply use fertilizer, irrigation, and calcium carbonate (to counteract acidity) on depleted soil indefinitely. We also have methods to farm sustainably. Cover crops gradually repair the soil during the off-season and are low cost. No till, manure, biochar are other options. Or we can just leave crop residues in place. As it is, half of earth’s soil has a lifespan of 1,000 years or greater.

Another cited extinction risk is that a single species of marine phytoplankton produces ~50% of oxygen. But the atmospheric oxygen reservoir is so enormous that we would be buffered for hundreds of thousands of years if oxygen production stopped completely.

Environmental activists make it sound like we are running out of freshwater. But only 2% of watersheds use 75% of their freshwater. Data centers are not draining our water supply. To be clear, we are choosing to pump truly preposterous amounts of water out of aquifers for agriculture, and this is unsustainable and bad for the environment. But we could be far less wasteful, recycling and desalinating way more. Surface water is returned annually so we aren’t going to “run out.”

Likewise phosphorus and nitrogen are not likely to run out. Phosphorous has 1,000 years of supply, and current processes lose 30% of the material during processing and extraction. It is not being recycled. Nitrogen is extracted from the air using natural gas, but can also be extracted using solar power with efficiency losses of 1%.

Oil, metals, chromium, and minerals are not ecological resources per se, but they have the same basic format - 1) there are vast deposits, 2) efficiency and alternatives are possible, just currently unnecessary.

In general, we would not hit a wall and face a catastrophe. There are moderately more expensive alternatives and we would switch to those once we started to experience scarcity.

Collapse Doesn’t Seem to Cascade

Cascading collapse doesn’t seem to occur in the unpredictable catastrophic ways depicted in the threat profile. This has been tested by multiple events of complete ecological destruction - cataclysmic volcanic eruptions, Agent Orange, mountain top removal, and other real-world instances of total ecological collapse. We didn’t see cascading collapses or unexpected bleed-over. We do see unexpectedly speedy and robust recoveries.

However, as ecosystems weaken, they will probably become more prone to these feared collapses. So the question is: how far can ecosystems collapse before they become unstable? The Netherlands has only 28% Biodiversity Intactness Index or 15% remaining biodiversity according to the Atlas Leefomgeving, yet it seems to not be notably at risk of ecological collapse. In this scenario of simultaneous correlated degradation, cascading collapse would need to cause the unexpected eradication of one of the non-redundant 5,000-100,000^[4] species necessary for human survival. But it seems likely that we would be actively tracking and managing the few species keeping us alive at such levels of depleted biodiversity. I think it would be more accurate to imagine this resembling a farming disaster, more than the usual depiction of an unforeseen ecological catastrophe.

More importantly, what would take us to that point of 99% global species extinction? Greed? War? Bioweapon? Climate apocalypse? Basically it would be other problems that would cause us to reach such a far-gone state, and ecological collapse could only really be the straw that broke the camel's back. It does not pose a current threat, nor a plausible future threat without bigger and worse catastrophes.

How bad does ecological damage get?

Ecological collapse won’t lead to human extinction. As an existential risk factor, it is small relative to other extinction risk factors. There are a lot of giant ecological catastrophes, but they are localized and not truly global-scale events. They don’t translate into a threat to civilization much the way earthquakes aren’t a threat to civilization or an existential risk factor. Ecological damage worsens humanity’s situation somewhat, but not so much worse that it demands specific attention as a contributing factor in existential risk. But what about the worst-case scenario for ecological disasters? How bad would it be? What if they all happened simultaneously?

This deserves its own article but I’ll enumerate some potential ecological disasters worth considering:

Landslides, flooding, storm surges worsened by deforestation. Soil degradation, desertification, salt water intrusion, other causes of permanently degraded productivity (including marine!). Herbivore overpopulation, pollinator loss. Invasive species, crop pests, toxic zooplankton, venomous species outbreaks, fungi outbreaks, vector/host outbreaks. Degraded sanitation, scavenger collapse, biomagnification (including toxins like ciguatera). Phytoplankton regime shift.

To get a sense of their size: Storm surges can kill in the 100,000’s, flooding can kill 1-2 million, scavenger collapse killed 100,000s. Degraded sanitation kills a few million annually, diseases kill millions annually, snake bites are about 100,000 annually. We would need to check how many were excess deaths caused by ecological amplification/failure, compare the damage from things like permanent lost productivity, and estimate how large these could get in worst-case scenarios. For now, it looks like disease burdens are probably going to be the worst ecological catastrophes.

Conclusion

There are three main proposed avenues of ecological-caused human extinction risk: 1) Resource depletion, failure of critical life systems, and cascading collapse. None of these pose a serious existential risk. For resource depletion, there are thousands of years of resources left with multiple alternatives we could switch to. For critical life systems failure, there are so many redundant species and so few species are needed to perform vital ecosystem services that we are thousands of years away from losing them all to extinction. For cascading collapse, there isn’t evidence of compounding synergistic effects from totally collapsed landscapes nor in regions of severely depleted biodiversity. Losing even a large number of species simply isn’t a realistic, pressing threat to human civilization -- so people should stop acting like it is!

There are Other Reasons to Care about Biodiversity

This post probably makes it seem like we are anti-conservation and think biodiversity isn’t worth protecting. That’s not true! The whole project of EcoResilience Initiative is to find the best ways to protect biodiversity, because we think nature is incredibly valuable and underrated.  Nature makes our lives richer and fuller, and the earth’s billion-years-long legacy of biodiversity is, considered as a whole, one of the most beautiful things in the universe.  It would be a shame to let all that beauty and complexity be eroded away by species extinctions during this tumultuous era of industrial civilization -- instead, we should find good ways of preserving nature so we can experience a more flourishing future.

This post felt like a tedious but necessary prerequisite for what I think is actually more exciting -- detailing what I consider the *real* top reasons to protect our planet’s biodiversity.  If you’re looking forward to that post too, then consider [subscribing] for our upcoming post in the sequence below!

* * *
 

This is part of a sequence on where the value of biodiversity comes from:
People really care about something they call nature
Nature's value mostly doesn't come from present-day benefits to humanity

And ecological collapse is not an existential risk

The real value actually comes from long-term flourishing.
Conservation in the next century is going to look a lot different than environmentalists think

Appendix

The “sixth mass extinction” does not Threaten Human Civilization

• We do not need a lot of species to survive.
  • About 25 macro species as a minimum from the MELiSSA closed loop long term life support pilot project.
  • About 10% of current biodiversity according to What We Owe the Future/Founder’s Pledge/John Halstead’s arbitrary back-of-the-napkin estimate in a footnote.

  • About 0.01%-1% or 5,000-100,000 species according to my estimate.^[5]

  • We also tend to respond when things that directly affect us are in danger. Livestock, pollination, water quality, air quality, fire, are all being managed now.
  • That’s a mass extinction event which would take 7000 years to come to pass at current extinction rates and assuming we don’t do anything.
• Countries with depleted nature are thriving.
  • The Netherlands has only 28% Biodiversity Intactness Index or 15% remaining biodiversity according to the Atlas Leefomgeving, yet it seems to not be notably at risk of ecological collapse?? Incidentally it has the fifth-highest GDP per capita in Europe.

Extinction Projections are Systematically Too High

• Extinction debt from habitat loss and climate change will be less than anticipated. Around 100,000 to 200,000 in my estimation (not 1,000,000 as in the typical estimations or this one at 400,000 just from climate.)
  • I think these are not accounting for niche shift, freak dispersal chance, and long-persisting-populations of species being rescued with tech development
  • Climate change will likely not exceed 3-4 degrees. Stronger climate change would be too painful, and geoengineering too cheap and easy not to pursue it. Climate change is slow and only affects 20% of species.
    • A report for What We Owe the Future/Founders Pledge contradicts this and places climate change at 0.6 - 3x the impact of land use. Land use change affects 80% of species.
  • Probably very few tree and plant species will go extinct. The paleontological record shows that they are resistant to extinction. Most likely due to their seed bank.
  • Many small species will disperse in freak events that give them good habitat, despite projections of being unable to migrate fast enough to keep up with climate change.
    • Island populations of terrestrial species are a good demonstration of how this happens across miles of un-traversible terrain, with enough frequency/size to start breeding populations.
    • I’m uncharitably assuming these sort of freak events are not built into models of climate migration, but I have not checked and should actually check.
  • Symbiotic species are not as “obligate” as they appear and most will survive much longer than predicted.
    • Example: The avocado tree is incredibly poorly adapted to propagating itself. Its massive seed is meant to be eaten by an herbivore the size of a ground sloth, which went extinct 10,000 years ago. But avocados managed to survive until the present day, despite such a clear obligate relationship being lost with no replacement. They ended up in small populations at the bottom of valleys due to their limited propagation.
  • Species in extinction debt are populations that are too small/under too much pressure to survive longterm. They are technically extant today, but they are on track to dwindle and go extinct to stochastic events.
    • Most species in extinction debt will continue to linger in microhabitats for hundreds of years, and will make it “out the other end” to de-extinction technology which looks to be about 65-120 years away (assuming further AI advancement and the time it takes to re-establish populations).
    • To be clear, breeding, habitat restoration, invasive species and predator management, disease management, acclimation to danger/shelter/survival are all obstacles between de-extinction and successful reintroduction. Reintroduction is a slow process even assuming you can de-extinct individual organisms in 40 years as Colossal is claiming.
• Habitat loss is currently mostly caused by agriculture. Agriculture is mostly livestock and livestock feed. Total habitat area occupied by agriculture has been declining because of increases in productivity and decreases in pastureland even as cropland continues to expand.
• Wind turbines are expanding around the globe, but mortality from wind turbines will drive almost no species to extinction.
  • Species that fly into turbines inhabit large ranges, some of which will almost certainly be outside the turbine area. Turbine mortality is a limiting factor, but not a cause of extinction.
• Population growth is not a major cause of extinction risk.
  • More people are moving in towards population centers faster than they are being born.
  • Growing food is getting more efficient and using less land per calorie.
    • In Africa in particular population is expected to grow but many land use efficiencies have not been applied yet.

Nor is resource exhaustion going to doom humanity

• Peak oil warnings were inaccurate
  • This was mainly due to fluctuations and trajectory changes with demand, innovation, refining, discovery, renewables, and more
• Soil loss and soil depletion is far from being a threat
  • We are not going to run out of soil carbon, nitrogen, and phosphorous for thousands of years
  • It’s not an unsolvable problem. Manure, crop rotation, and other basic practices address it.
  • Theoretically we can invent additional ways to repair soil faster. I assume we have not done so because it is not yet a serious problem. Actually it looks like I’m wrong about that and it is fundamentally a slow process that you would realistically do on-site.
  • Here is an EA post covering phosphorous depletion risk
  • And an 80,000 hours interview that discusses nitrogen depletion
• Metal and mineral depletion I assume are a similar non-issue
  • There are deposits of minerals on the ocean floor, there are improvements in refining, efficiency, alternative materials etc.
  • Here is an EA post discussing how much minerals are needed for the energy transition.
  • And another post about resource depletion risk generally.

Nor is cascading ecosystem collapse going to doom humanity

• 1000 years ago there were massive extinctions of all major predators around the world and this didn’t cause human collapse with prehistoric technology. The ecological devastation was largely undetectable to us.
• There are fears of potential compounding synergistic effects/extinction vortex/poly crisis. But we haven’t seen signs of this happening anywhere at any point in history yet.
  • It seems like a good thing to watch for, but fortunately not a present threat or at least a very rare one. I think it’s advisable to increase our uncertainty to reflect this possibility when projecting earth systems.
• There are many examples of ecosystem recoveries in record time.
  • Even when we look at completely devastated areas like massive volcanic eruptions/agent orange/etc they don’t cause a cascading or runaway collapse of adjacent ecosystems and then tend to recover in 40-80 years.
• Repeat stress events are reducing the environment's ability to recover.
  • Degraded lands are thriving, just populated with invasive, common, generalist species.
  • I need to look into this in more detail. My general feeling is that this is true but not threatening until habitats have lost 80% of their biodiversity.
• I have tried to identify the worst cases of ecosystem collapse and cascading impacts, and found very few (6) documented examples. None of these caused adjacent ecosystems to collapse?
  • Those six examples were:
    • Starfish die-off converted kelp forest to urchin barrens.
    • Mountain lion absence causes increased herbivores, decreased vegetation, changed stream patterns, and decreased insect biodiversity. (This is a replication of the return of wolves in Yellowstone.)
    • Amazon fragmentation causes species decline over decades.
    • Moa eradication and mammal introductions in New Zealand causing 50% herbivorous bird extinction, widespread plant extinction, and decreased nutrient inflow.
    • Deforestation in the Amazon combined with temperature rise is drying out the forest and the resulting fires are converting it to Cerrado (savanna).
    • Sea level rise in the Everglades is causing mangrove dieback, and subsequently sawgrass dieback and coastal erosion.
      • But this is mostly the physical presence of salty seawater pushing inland, so not a great example of a cascading collapse.
    • I’m interested in reading about more examples in this category of extreme ecosystem regime changes, please send them my way!
  • Some of these were drastic regime changes to the ecosystems, but they do not cause adjacent ecosystem collapses nor threaten human survival.
    • Cascading collapse seems to happen more often from climate change - where the fundamental physical parameters have changed underlying ecosystems - and not the feared unpredictable emergent phenomena.
      • Tipping points that have been identified from climate change don’t appear to threaten the future survival of civilization.
      • 80,000 hours and other EA orgs have concluded that the survival of human civilization is not at risk from climate change.

1. ^{^}

    I’m not aware of other kinds of ecological risks, but I would be interested to learn about other examples

2. ^{^}

    To get a rough global estimate of required biodiversity for ecosystem services, I multiply each species required count from this table by the number of global biomes (85-500) and get ~5,000-100,000 (0.01%-1% of total extant species). Total biomes are somewhere between 85 (at the Formation level, which would be minimizing global species) and like 500 (at the Division level which would be using locally thriving species). Totaling that up comes out to somewhere between 7,480 (0.086% out of all extant species) and 81,500 species (0.94%) to support global ecosystem services. Flaws with this estimate: There are unlisted ecosystem services. I’m overcounting habitats since biomes like “ephemeral salt lakes,” “ground water” and “mud plains” would provide more limited sets of ecosystem services. Some species could fulfill multiple ecosystem services. Some species could fulfill multiple biomes. Supporting ecosystem services would be needed. I think this estimate is really low, but far more than required for a handful of humans to survive.

3. ^{^}

    There are multiple steps to nitrification and the most limited one is Ammonia oxidation which is provided by only three guilds: AOA, AOB, comammox. Of those, anammox is only six genera, one phylum.

4. ^{^}

    To get a rough global estimate of required biodiversity for ecosystem services, I multiply each species required count from this table by the number of global biomes (85-500) and get ~5,000-100,000 (0.01%-1% of total extant species). Total biomes are somewhere between 85 (at the Formation level, which would be minimizing global species) and like 500 (at the Division level which would be using locally thriving species). Totaling that up comes out to somewhere between 7,480 (0.086% out of all extant species) and 81,500 species (0.94%) to support global ecosystem services. Flaws with this estimate: There are unlisted ecosystem services. I’m overcounting habitats since biomes like “ephemeral salt lakes,” “ground water” and “mud plains” would provide more limited sets of ecosystem services. Some species could fulfill multiple ecosystem services. Some species could fulfill multiple biomes. Supporting ecosystem services would be needed. I think this estimate is really low, but far more than required for a handful of humans to survive.

5. ^{^}

    To get a rough global estimate of required biodiversity for ecosystem services, I multiply each species required count from this table by the number of global biomes (85-500) and get ~5,000-100,000 (0.01%-1% of total extant species). Total biomes are somewhere between 85 (at the Formation level, which would be minimizing global species) and like 500 (at the Division level which would be using locally thriving species). Totaling that up comes out to somewhere between 7,480 (0.086% out of all extant species) and 81,500 species (0.94%) to support global ecosystem services. Flaws with this estimate: There are unlisted ecosystem services. I’m overcounting habitats since biomes like “ephemeral salt lakes,” “ground water” and “mud plains” would provide more limited sets of ecosystem services. Some species could fulfill multiple ecosystem services. Some species could fulfill multiple biomes. Supporting ecosystem services would be needed. I think this estimate is really low, but far more than required for a handful of humans to survive.

6. ^{^}

    These are some of the claims made by large and reputable environmental organizations: “Biodiversity is earth’s life support system.” “Nature gives us a habitable environment, we rely on clean air and water.”  “We depend on nature for survival.” These claims are phrased to imply extensive environmental actions are important for human survival, which is not actually supported.

7. ^{^}

    Most water treatment plants are chemical and physical processes. This is because biological processes are slower and less controlled.

8. ^{^}

    The planetary boundaries say we have already crossed this boundary, at losses of "10 extinctions / million species years." The planetary boundaries represent boundaries past where we "do not know," not when we "will likely cause serious damage to civilization." I’m not even sure if the rate of extinction boundary is helpful because collapse risk would depend on how many species total are left, not the rate of decline?

9. ^{^}

    Natural salt flats, sand dunes, rocky alpine, and taiga forest all have very low species diversity. Other examples are tree plantations and farmland with monoculture crops, and cheatgrass invaded sagebrush habitat (reduced down to 8 species of plant). These are not "uninhabitable" due to low biodiversity although they may be physically inhospitable. They are not collapsing dustbowls with no water and oxygen.