Sharing vs Sparing: The key point everyone's missing with "Infinite growth on a finite planet"

Carrying Capacity is an ecological concept that has grown in importance over the last century, particularly as it relates to the sustainability of human populations. It refers to the maximum population size of a species that an environment can sustain indefinitely, given available resources and constraints.

A range of megafauna that used to inhabit Australia, and were driven to extinction by Australia’s first peoples about 50,000 years ago. Source

Malthus was the first key figure who popularized carrying capacity in relation to human populations, and more recently Paul Ehrlich (The Population Bomb) and the Club of Rome's "Limits to Growth" (1972, but updated in 2004 primarily by Dana Meadows), all the way to Kate Raworth’s Donut Economics, “Earth Overshoot Day,” and Johan Rockström’s work on Planetary Boundary Framework.

from Kate Raworth’s website, Donut Economics laid a social foundation and an ecological ceiling mapped against planetary limits, with an assertion that human societies must strive to operate within the donut. “Within the donut” means that humanity is not overstraining earth’s carrying capacity across a number of variables, while achieving a standard of living for all humanity across a different set of variables.

Each of these concepts deserves their own fleshing out, but I’m not going to do that in this article. The older versions (Malthus & Ehrlich in particular) do not carry much weight, because they made predictions that were proved wrong. However, there’s a great deal of value here, particularly in understanding the patterns of why they were wrong, and what they got right. I’ll get to that eventually, but there is a critical piece of the conversation missing in all of this:

The carrying capacity of earth is not fixed, but collapsable and expandable. This fractals down to microclimates and up to macrocycles and the planet itself. I have personally experienced the contraction and expansion of carrying capacity of a desert in Saudi Arabia, at the Al Baydha Project, which I cofounded and managed for 8 years. At the start of our project, human mismanagement had degraded the watershed we worked in to the point that the water cycle was broken, almost no photosynthesis took place, and the carrying capacity of that land was approaching zero. And yet through experimentation, prototyping of applied ecology and applied hydrology, the carrying capacity of that watershed is now increasing without additional human intervention. The limit to the carrying capacity of that particular area is water, but the water cycle is cycling more frequently, meaning the land’s capacity to foster life is increasing, while water resources are also increasing. At some point it will reach a new equilibrium, with an explosion of photosynthesis, mycellia, and the resulting increase in animal life.

Satellite data of the increasing photosynthesis on our site at Al Baydha, taken from my update written on linkedin in 2023: https://www.linkedin.com/pulse/update-al-baydha-9-years-later-neal-spackman/

My experience at Al Baydha speaks directly to the concept of “infinite growth on a finite planet”. While there is a finite amount of surface area of earth, a finite amount of exploitable minerals, a finite amount of water and soil, a finite amount of sunlight hitting the planet, and even a finite amount of time in which earth will support human life (given that the sun will transform into a white dwarf in 5 billion years), these are not what determine the carrying capacity of earth. Rather, they are parameters.

The yield of a system is theoretically unlimited, and only limited by the imagination and information of the designer.

Bill Mollison, co-inventor of permaculture

What determines the carrying capacity of earth is us. Humanity. People. We are the keystone species. We are what determines if earth’s carrying capacity expands or contracts, and we make that determination in how we manage the systems and resources that maintain the conditions for life: soil, water, biodiversity, and ecology. This is the most important implication of what it means that we are the keystone species, and a key factor that both the sharing and sparing sides of the argument get wrong.

I’ll write just a little on homo sapiens causing the contraction of earth’s carrying capacity, but one that avoids blaming anyone alive. As it turns out, our earliest ancestors reduced earth’s carrying capacity, providing a simplified example compared to all the ways we’re mucking things up today. The first peoples of every continent, except Africa, drove megafauna to extinction. Curiously enough, in Africa the megafauna had enough time to adapt to humans as a predator, but the megafauna elsewhere had no such luxury. The resulting extinctions reduced earth’s carrying capacity significantly (note that I am not saying that all of these species were driven to extinction by people, but at least some of them were, with the same resulting ecological consequences).

Americas

When humans crossed Beringia (13,000-15,000 years ago), North America lost approximately 70% of its large mammal species, including:

• Mammoths and mastodons

• American horses

• Several camelid species

• Ground sloths (some weighing several tons)

• Short-faced bears

• American lions

• Saber-toothed cats

• Giant beavers

• Dire wolves

The ecological consequences of these extinctions were far-reaching. Large herbivores had played crucial roles in nutrient cycling, transporting vital elements across diverse landscapes through their movement and excretion. Without megaherbivore grazing, fuel loads increased significantly, intensifying wildfire patterns across the continent. The vegetation structure shifted dramatically from mixed grassland-woodland mosaics and savannahs (the most diverse and productive terrestrial ecosystems) toward more closed, dense forests as the browsing pressure from large herbivores disappeared. Additionally, many large-fruited plants that had coevolved with megafauna for seed dispersal struggled to propagate effectively, altering plant community compositions throughout the Americas (the Osage Orange is a good example of this)

Europe

European megafauna extinctions occurred more gradually as humans expanded throughout the continent (40,000-10,000 years ago):

• Woolly mammoths

• Woolly rhinoceros

• Cave bears

• Cave lions

• Irish elk (giant deer)

• Steppe bison

The loss of European megafauna transformed the diverse steppe-tundra "mammoth steppe" ecosystem into more homogeneous forests and tundra landscapes. This transition significantly reduced habitat heterogeneity that had previously supported diverse ecological niches and species assemblies. The absence of large mammals disrupted crucial nutrient redistribution pathways across landscapes, as these animals had transported nutrients between different habitat types. Vegetation composition shifted noticeably toward plants with smaller seeds and different growth forms, as the selection pressures from megaherbivore browsing and grazing were removed. Together, these changes reduced the land's capacity to support the same biomass and biodiversity that had existed previously, as both nutrient and water cycling were reduced.

Asia

Asia experienced a more complex extinction pattern with regional variations:

• Woolly and steppe mammoths

• Various rhinoceros species

• Giant deer

• Cave hyenas

Northern Asia's ecosystems underwent transformations similar to Europe's, with reduced grazing pressure fundamentally altering grassland dynamics and productivity. The changed herbivory patterns led to shifts in fire regimes, which further reinforced transitions in dominant vegetation types. Without megaherbivores creating and maintaining habitat mosaics, landscape heterogeneity decreased significantly. The ecological impacts were less pronounced in southern regions of Asia where some megafauna, including elephants and rhinos, persisted, allowing these areas to maintain greater ecological continuity and higher carrying capacities compared to northern regions where extinctions were more complete.

Australia

Australia experienced the most severe extinctions driven by humanity (approximately 50,000 years ago):

• Giant wombats (Diprotodon)

• Marsupial lions (Thylacoleo)

• Megalania (giant monitor lizard)

• Giant kangaroos

• Genyornis (large flightless bird)

• Several other large marsupials

The ecological consequences of Australia's megafauna extinctions were particularly profound and transformative. The continent experienced dramatic changes in fire regimes as vegetation that had been kept in check by megaherbivores grew unchecked, providing greater fuel for wildfires. This triggered a continental shift from fire-sensitive vegetation communities to fire-adapted ones, fundamentally altering Australia's ecological character. Many large-fruited plants lost their primary seed dispersers, changing reproduction patterns and plant distribution across landscapes. Ecosystem fertility declined markedly as the nutrient cycling services provided by large animals disappeared, with fewer nutrients being transported from nutrient-rich to nutrient-poor areas. Some regions likely experienced increased desertification as the combination of changed grazing patterns, altered fire regimes, and reduced soil fertility created feedback loops that decreased the land's ability to support vegetation and retain water, substantially reducing the ecosystem's overall carrying capacity.

Imagine if thousands of years ago our ancestors had possessed the foresight to preserve and protect some of those remarkable creatures! What unspeakable loss! More recently, the loss of the passenger pigeon, the American chestnut, and the resulting drop in food production capacity in North America, have at times made me deeply sad, not just for the loss of life, but the loss of beauty, the loss of experience, and the loss to current and future generations of diverse food pathways and experiences. If I had my druthers, I’d create the right ecological context and Jurassicpark those critters and those plants that were once a staple part of indigenous food systems to people on my home continent (yes, Jurassicpark is now a verb and all of you know exactly what i mean) . But I’m getting off track.

I don’t have enough space in this post to go into how we can expand earth’s carrying capacity, given the parameters noted in the donut economics image above, but the takeaway is this:

The landsharers are 100% correct that there are ecological and geographic finitudes that limit growth. It is 100% correct that we compromise the viability of human civilization when we degrade their ecological foundations —whether that’s air pollution, nitrogen overload in the oceans, soil loss, biodviersity loss, water depletion, etc.

But the landsharers are wrong that these are what determine the carrying capacity of earth. These are the parameters around which we must design our civilizations, and the parameters that we, as people, can use to either increase or degrade earth’s carrying capacity, through our own management as the keystone species.

Another area where the landsharers are wrong, is in their estimation of humanity. We are the most adaptable species on the planet (mycellia gives us a run for the money though). No other species has learned to occupy every terrestrial ecosystem on earth; from the inuit in the arctic, to the bedou of the Sahara, and everything in between, our greatest strength is our capacity to adapt. No other species has developed the ability to escape earth’s orbit, or even contemplate being able to exist off-world (Again, Mycellia could probably survive Mars better than we could, but it’s never felt the need to contemplate it). We are extremely good at adjusting and adapting to a crisis (tho unfortunately we are terrible at preventing them, even when we can see them coming).
What I’m saying is that imagination, creativity, and adaptation are our greatest quality, and it was the underestimation of those qualities that made Malthus so wrong, and that has made so many other catastrophic predictions made by folks in the environmental movement seem so silly in hindsight. It’s often fallacious to look at today’s trends, project them into the future, and say “in 30 years reality will be like this.” Because we do adapt.

I hope my next post will be the antepenultimate in this series, as we still have to talk about degrowth vs true growth, and population, but after those I’ll summarize the sharing vs sparing arguments, highlight what both get wrong and right, and then synthesize the whole discussion.

~Neal

PS, as usual I’m writing this in a fit of productivity in the wee hours of night, in between pursuing a handful of endeavors. I expect there are typos in here: If you’re the first to find one, write me and if you’re the first one to find one i’ll send you a thank you note.