Carrying Capacity

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Contextual Quote

"What’s particularly pernicious about crossing carrying capacity thresholds is the potential for amplifying feedback loops to trigger tipping points, thus exiting the relative stability of an existing state of a system in a non-linear phase shift to an altogether different (and inherently unpredictable) systemic state. Think of climate chaos as transgressing the carrying capacity threshold of temperature stability (the best science says the dividing line is 1.5C) tipping us into a hothouse earth, or the spontaneous 1960s riots against racism in the US or the more recent Arab Spring that crossed the carrying capacity of social justice. In each of these instances, there are vital resources that underpin stable systems, and if these resources are depleted, or if we fail to regenerate new resources, we risk crossing carrying capacity thresholds." [1]

- Bill Baue and Ralph Thurm


Murray Lane:

"Carrying capacity is a concept suggesting that populations are constrained in their behaviour and in their number by the biophysical limits of the landscape upon which they are supported. In accord with Meadows’ et al. hypothesis, which is best summed up by the title of their book, The Limits to Growth, the concept of carrying capacity inherently acknowledges and measures these limits. In the contemporary Australian context, such biophysical limits are not always recognised, with societal and economic systems often viewed as operating outside of an environmental context. However, a societal awareness of these constraints is an essential element in the sustainable long-term survival of any population because transgression of such biophysical limits can lead to both population collapse and environment degradation. This research explores some of the constraints to population carrying capacity, particularly in the Australian context.

In both academia and society at large, carrying capacity theory and practice is an under-developed science. The parameters involved in its calculation, an understanding of how it is performed and the components necessary for an accurate and detailed carrying capacity assessment are generally not well documented or understood." (


Murray Lane:

"While the application of carrying capacity analysis has differed throughout history, essentially the concept remains unchanged. Kirchner et al., suggest that carrying capacity analysis, applied to wildlife, aims to, “express the capacity of natural areas (ecosystems) to support animal life.” Similarly, when applying the concept to the measurement of human carrying capacity, areas of land are assessed for the extent to which they can support human life. For example, a carrying capacity estimate may suggest that a particular piece of land might support say, 1000 people. In this example, the answer to the carrying capacity equation is relatively simple - 1000 people - but the complexity lies in the assumptions underpinning the estimation.

Consequently, variations in the definition of carrying capacity tend to differ in their exploration of what these inherent constraints entail. For instance, House and Williams define the concept as, “the level of human activity that a region can sustain at acceptable quality of life levels,” inferring a bias towards qualitative societal constraints. Alternately, Whittaker and Likens take a more ecologically quantitative view of carrying capacity in describing it as, “the size of the human population that can be supported on a long-term, steady-state basis by the world’s resources without detriment to the biosphere.”

Even though most carrying capacity definitions infer a process for the measurement of causal relationships between a population and its landscape, many only do so from an abstract perspective without the inclusion of summative calculations. Hopfenberg states that, “[a]lthough models for human carrying capacity exist, they are typically tied to theoretical constructs rather than biologic data,” urging proponents to transition from, “the theoretically derived carrying capacity to an identifiable and quantifiable one.” In short, qualitative carrying capacity analysis tends to examine population dynamics without ascertaining any actual numerical result while quantitative assessments add calculation to the theory. As such, a qualitative definition of human carrying capacity may be - the ability of a certain area of land to support human life, while a more quantitatively orientated description may be - the maximum number of people that an area of land can support." (


Murray Lane:

"The first known use of the-term carrying capacity occurred in 1845 in a report by the U.S. Secretary of State declaring that a new tax would differentiate between cargos transported on sailing- and steam-boats because of their differing carrying capacities. While probably initially used just as two discrete words to best describe a ship’s maximum payload, the term carrying capacity subsequently gained its own unique meaning through increasingly frequent use. Firstly applied to just ships, then to other modes of transport such as trains, the term began to take on a broader meaning by the late 1800s. Sayre explains that eventually, “the term shed its connection to the levying of duties” and, “refers to the amount of X that Y was designed to carry.”

Initially the “Y” in Sayre’s equation referred predominantly to man-made vessels but 1886 marks the first known occasion for its application to a landscape where reference was made to the “stock-carrying capacity of the country.” While it can be assumed that pastoralists may have commonly had a reasonable idea of how many animals their land might potentially carry, the term became bureaucratically entrenched in the U.S. at a time of agricultural expansion in the late 1800s.

Clements argues that quantitative carrying capacity estimates, assigned to new farming allotments, more easily allowed government to compare and regulate new lands and bankers to more readily capitalise the process. The use of the term carrying capacity in relation to the density of livestock on a given piece of land is still prevalent today.

Once the quantification of maximum livestock numbers was entrenched in farming practice and regulatory structures, it became evident that the concept could equally be applied to native wildlife and by the 1920s, game managers began estimating the number of deer, quail and other game species natural environments might support. Aldo Leopold, for example, advocated a greater awareness of the factors influencing carrying capacity in his 1933 publication, Game Management, and in so doing, heavily influenced wildlife managers for generations to come.65 Consequently, Sayre argues that carrying capacity approaches to wildlife planning in the twentieth century were responsible for positive outcomes, such as the stabilisation of numbers and distribution of species, but also for ongoing problems such as compromising genetic diversity and ecosystem function through the manipulation of otherwise natural processes.

By the 1940s attention turned to the possibility that carrying capacity could also be applied to human populations and Leopold, again, was at the vanguard. For example, in 1941 he compared the human carrying capacity of America to precolonisation levels for indigenous Americans, concluding that, “[w]hen we arrived on the scene we raised the carrying capacity of the land for man by means of tools.”

In 1949, William Allan actually performed a carrying capacity analysis of swidden agriculture traditionally practised by the people of Northern Rhodesia in Africa.68 According to Cohen, there were various previous carrying capacity calculations world-wide prior to this time, but none that defined the process as a carrying capacity assessment. Allen utilised three types of data to derive “a method of estimating land carrying capacities for human populations under African conditions and systems of land usage,” and estimated population carrying capacities for various regions with an average of eight people per square mile." (


How the carrying capacity rates of renewable and non-renewable resources may be applied to the economic and monetary system

James Quilligan:

"First, the carrying capacity rate for renewable resources follows a carefully guided policy of maintenance and sustenance to ensure that resources are replenished sustainably in meeting the needs of people in the present (meanwhile, the needs of people in the future are in no jeopardy, so long as renewable resources continue to be replenished and provisioned within their carrying capacity - hence, the carrying capacity rate of renewables is geared toward market coefficients for provisioning for people in society at the current time (and will continue to be sustainable far into the future) - this rate based on renewables in no way precludes (in fact, should be accompanied with) the creation of taxes toward a universal basic income and for maintenance of the renewable resource)

Second, the carrying capacity rates of non-renewable resources are treated quite differently - society must decide scientifically how much non-renewable resources to use in the present and how much to save for the future - by guaranteeing that valuable resources will be 'left in the ground' or put away securely into a tamperproof lockbox, as it were, this formula has a benefit which, in one way, is similar to how gold used to function - since a certain percentage of non-renewables are held in strict reserve for future generations, adherence to this process creates a value which is entirely *independent of the market and is based on a relative scarcity index (sorry that it doesn't glitter, too)- this fraction (how much non-renewables to use for people now / how much non-renewables to set aside for people in the future) provides for a fixed and stable monetary rate that is tailor-made for the valuation of currency in the present - in a society which is facing net energy loss and steep declines in non-renewable resources, this would be an extremely stable, strong, treasured, desired, sacrosanct and entirely non-marketized value - thus, instead of commodity market rates, inflation or unemployment, or currency exchange rates, monetary economists really ought to be turning their attention to sustainability rates - in conclusion, I have never advocated returning to a gold standard, but to a policy of currency values which are fixed to a meaningful measure of non-renewable resources, similar in some ways to the way that gold used to operate - and that is what I have outlined for you above." (

Are capital-based accounting systems the right approach ?

Mark McElroy:

"Perhaps the single most important feature of the International Integrated Reporting Council’s (IIRC) proposed standard for integrated reporting is that it is capital-based. It is predicated, that is, on the view that organizational performance — both financial and non-financial — is a function of what a company’s impacts on vital capitals are, given the importance of such capitals for human/stakeholder well-being.

Indeed, the fact that performance is a function of impacts on vital capitals is arguably the least controversial claim in the sustainability literature, and is all but taken for granted in financial management. Financial performance, that is, is a function of an organization’s impacts on financial capital, and non-financial performance is a function of its impacts on natural, human, social, constructed (or built) and intellectual capitals. The latter, intellectual capital, is sometimes embedded in the preceding three.

Importantly, another emerging standard, the Global Initiative for Sustainability Ratings (GISR), is also capital-based. It, too, is predicated on the view that sustainability performance is a function of impacts on vital capitals.


Both standards deserve to be supported in the strongest possible terms, if only because of their grounding in capital theory. Impacts on capitals — in light of the role they play in human/stakeholder well-being — determine an organization’s real performance. Performance measurement, reporting and rating systems should be constructed accordingly.

The Global Reporting Initiative (GRI), for its part, is woefully behind on this issue, if not willfully dismissive of it. In the recently released update to its sustainability reporting Guidelines (G4), the proposition that GRI add a focus on capital impacts as a requirement for reporting was rejected. Sadly, this portends another five or six years of dubious — yet still GRI-compliant — reporting, because without assessments of impacts on vital capitals, sustainability reporting, per se, cannot be done.

To be clear, neither the IIRC nor the GISR speak in terms of the carrying capacities of vital capitals — not yet, anyway. In principle, though, the inclusion of the idea that capital stocks and flows have carrying capacities is essential to the capital-based view of performance, because the fact that impacts on capitals can increase or decrease the quality or sufficiency of such capitals is precisely what makes them relevant. Indeed, human well-being depends on them.

It is not enough, then, to simply say that an organization’s operations have had impact on water resources (a type of natural capital); rather, the question must be: Have its impacts diminished the quality or sufficiency of such resources at levels required to ensure human (and non-human) well-being? Assuming we can allocate shares of natural resources to specific organizations – which we can – actual use then can be compared to such allocations as a basis for assessing performance. The concept of carrying capacity provides us with just the kind of measurement model we need to perform such calculations." (

Applying carrying capacity insights to the Coronavirus crisis and response

Bill Baue and Rallph Thurm:

"Let’s apply this multi-capital approach to the Covid-19 crisis, first examining how we risk crossing dangerous carrying capacity thresholds.

Financial Capital:

At the same moment that traditional measures of financial capital are curving downward precipitously, as stock markets tumble across the globe, so too are we in greatest need of financial capital to support our wellbeing. Financial carrying capacities apply to the healthcare system (a “floor” of financial support necessary to keep the system afloat amidst the intense demand), the social infrastructure system (“shelter-in-place” orders prevent millions of citizens from working, risking falling beneath the financial floor of subsistence), business systems (which are similarly reeling from downed supply chains, market demand, and work disruptions), and market systems (stock markets are regularly hitting the carrying capacity of price crashes, triggering automated market shutdowns). Governments are allocating financial capital to buoy the carrying capacities in these various systems, primarily by “printing money” through deficit spending while praying that such debt accumulation does not cross its own carrying capacity. As our colleague James Quilligan of Economic Democracy Advocates asks, “how long until you grasp the real connection between our monetary debt and our ecological debt?”

Natural capital:

Professor Jem Bendell, who conceived the Deep Adaptation concept, draws a direct link between the Covid-19 crisis and the climate crisis. It is remarkable that at a moment when the lungs of the world are burning at ecocide levels, humans are met with a lung disease. And this abuse of natural capital has its origins in the abuses of the neoliberal model of financial capital growth. The decrease of availability of capacity of humans to counter pandemics and epidemics now and in the future has a direct correlation with natural capital overuse. We are now entering the final downward spiral of losing resilience being able to survive this and other crises in the future. We overshot thresholds in many ways and have allocated this overuse into market designs that now allow viruses to spread in high speed. Economic system design disconnected from natural capital availability are deadly and need to be corrected as soon as possible.

Manufactured Capital:

The need of the health care system for technology, machines, testing, and supplies for personnel up to the maximum of capacity in hospitals defines the threshold of manufactured capital. Overshooting healthcare system carrying capacity leads to their collapse at the moment of highest need. Ironically, many hospitals abandoned their slack capacity of additional beds and supplies, following the logic of “just-in-time” supply chain maintenance pioneered by Toyota in the 1980s. Allocation of the available manufactured capital, human capital, and social capital to areas with the highest amount of infections is now a daily challenge for governments and suppliers of the health care system.

Human Capital:

The knowledge, skills, experience, and expertise of individual healthcare professionals represent vital human capital, which is reaching the threshold of its carrying capacity for deployment to handle the mushrooming Covid-19 cases. Health care system budgets everywhere are in decline (and costs are increasing), so we already face a lack of trained health care sector employees.

Social Capital:

A society thrives through collaboration and interaction. The Corona crisis is reducing physical interaction, and increases the possibility of violence. Already now the amount of violence in lockdown areas has tripled and separation of elderly people leads to social isolation. This has considerable mental and psychosomatic consequences in a population. Regular interaction with loved ones and friends, collaboration between businesses in trusted ways, and intercultural exchange define a threshold of ‘balanced interbeing’. Allocation normally happens automatically by befriending, joint experiences and moments of success with each other. That possibility is missing in a time of lockdown." [2]