The World4.5 Demographic Model

Working With James C Morrow and Chris Bystroff

Early on in my activism (2020), I was approached through an email from James C Morrow. Our correspondence and our friendship has grown as we combined forces to change attitudes using our very different abilities and skillsets. We met during a zoom event where an unpublished demographic model was being presented by Professor Chris Bystroff.

The picture above is the figure 4 from the Bystroff model. When I saw the ‘Business as Usual’ line that predicted imminent population collapse, it immediately rang true to my mind. The demographic predictions that are offered by the United Nations do not factor in the ecological degradation that we inflict on eco-systems. Therefore, they become increasingly unreliable as the global ecosystems collapse escalates. Because most scientific journals recoiled from publishing such tragic predictions, this model was not peer-reviewed for nearly a year, and was eventually published in 2021.

At the time, like James Morrow, I instinctively focussed on the patterns rather than the specific figures. More recently James has told me about about G?del’s theorem, which confirms the wisdom of using that approach to mathematical models.

Confident that the Bystroff predictions were valid, I had already referenced his model in my self-published book. My own social science paper has met with six rejections before being submitted for peer-review, and the peer-review has now gone on for six months (Dec 2023). This is despite the fact that there is no new science in my paper, it only offers recommendations going forward. Ideas like a voluntary global birth strike are clearly causing considerable consternation amongst the peer-reviewers. Chris Bystroff thought that I might outstrip his record for journal rejections, but in the end I had one less, with six rejections.

I asked Population Matters to share the Bystroff model with their membership, but to date they have recoiled from taking this step. They have however, begun hinting at the need for economic Degrowth in their communications. I am sharing this background to help readers to understand why these predictions are not widely known. As far as I am aware, there is no population, or environmental NGO that has shared this demographic model with their members.

I shared the Bystroff model with numerous academics, newspapers, and NGOs, nobody was willing to even discuss the model. James Morrow has recently found a university willing spend some time interpreting the mathematics into layman’s terms’ during 2024.

The rest of this article is an extract from an email between James and the person who has agreed to take the matter forward. I am hoping that you will find the holistic perspective helpful. BAU means Business As Usual. The final section from James email is a helpful endorsement for someone like me who does not have the mathematical skills to fully grasp the model. My connection with James and Chris gives me the confidence to use my wordsmith skills to promote the global ambition to equitably limit human impact to half the biocapacity available.

Analysis of the median business-as-usual projection

The World4 model is a BAU projection in the sense that human growth behaviour and behaviour towards the environment are treated as parameters that are determined by fitting past population data, not parameters that in any way seek an outcome. A range of parametric solutions has been found by the process described here. Each solution fits past population data the same but projects differently into the future. The median projection (Fig 1) peaks at or around 2022, then falls steeply, levelling off at around 3 billion by 2060. The cause of the decline within the model is a decrease in the food supply caused in turn by degradation of the environment and the concomitant attenuation of essential ecosystem services.

The model reflects the current thinking on climate change and its repercussions. Climate change leads to weather uncertainty, increased severe storms, draught and floods, and sea level rise affecting low-lying areas — each a factor in decreasing agricultural output. Increased hunger in turn fuels conflict [30, 31]. Conflict leads to further decreases in food production and to mass migration, as we have seen recently from the rapidly heating Sahel region of Africa [32, 33]. In the BAU projection we see an increase in human mortality, followed by a decrease in carrying capacity. The recent worldwide spread of Covid-19 is an example of an emerging source of mortality for which human technology was not ready. Societal stressors such as hunger or a pandemic can drive violent behaviour [34]. In the median projection, following the peak, population drops quickly, accelerating to 100 million net lives lost per year through the years 2030 to 2040, which is faster than the fastest growth during the 20th century. In this model, we clearly see the cause of the rapid decline — the exponential growth of the consumption of finite vital natural resources.

Real world examples of current ecosphere collapse

We are beginning to see the effects of the decline of natural resources and ecosystem services. Fossil fuels, fresh water aquifers, and greenhouse gas sequestration by plants are all regarded in this model as part of the ecosphere since they are not generated by human activity. The decline of one or more natural resources is cited as a cause of, for example, the ongoing deadly conflicts in Syria starting since 2011, the conflicts and famine in Yemen beginning in 2015, and the economic collapse in Venezuela that began in 2014, to mention a few. Draught and desertification were blamed for conflicts and mass migration out of the Sahel region of Africa, where Lake Chad has all but disappeared.

Conflicts and famine have produced millions of refugees. Innumerable lives have been lost crossing the Sahara or crossing the Mediterranean, or in primitive camps along the southern borders of Europe. The 2017 documentary film “Human Flow” [35] reveals the massive scale of the refugee issue. Meanwhile, the global north has responded to the aggregate changes of the last 50 years with a dramatic decrease in the birth rate. An increasingly technological workforce has meant women spend more time in school and marry later. Rising oil prices have steadily ramped up the cost of raising a child, leading to smaller families by choice. Total fertility rate (TFR) globally is projected to reach replacement level (2.11) this year, 2020.

Real world examples of the predicted decline of technology

Along with ecosystem decline, the model predicts changes in technology. In the projection, knowledge will be lost or made obsolescent during a population collapse. Much of our cultural technology is composed of laws, governance and economics. In recent economic history, consumerism has become engrained in our culture [36, 37]. Stability and prosperity in the context of the current economic system relies on population growth, according to economists. A technology shift in economics is likely when population begins to decline, since growth-based economic systems and the associated body of knowledge will become obsolescent in the sense that they will not produce stability. In effect, economics will have to be re-learned.

Obsolescence of growth-based economics may manifest itself in real-world breakdown in economic systems leading to decreased efficiency in manufacture and trade, in turn leading to a decrease in the effective food supply, which in turn will cause an increase in malnutrition and a decreased birth rate. Already, increased adult mortality and decreased birth rate are both current trends in global vital statistics [38]. In other areas, medical technology is partially responsible for a historic low death rate worldwide, but successful treatment of disease requires instruments and drugs that depend on a complex supply chain and high level engineering skills. In the event of an economic shift, supply chains will be disrupted unless a new system of economic motivation is quickly invented to replace the growth motive. In agriculture, technology to increase crop yields will become obsolescent as climate challenges, biodiversity losses (especially the loss of pollinating insects), and depletion of freshwater aquifers, combine with economic changes to reduce the efficiency of food production and distribution.

Hopeful what-if scenarios as add-ons to World4

The future could easily be different than what is predicted by World4. World4 does not model changes in attitude and policy. Humanity could adapt in ways that may be good or bad. Modelling adaptation mechanisms opens a non-BAU modelling space that is too large to thoroughly explore. Taking inspiration from E. O. Wilson’s book “Half Earth” [39], parameters for policies to preserve wild nature were implemented. Four new variables were added, w, y, py and sy, as defined in Table 1, for the target amount of ecosphere to save, the level of policy enforcement, the phase-in period and the date on which the policy begins, respectively. These variables do not affect populations prior to and including 2010. Preserving wild land wild allows humans to thrive. The optimal result (coincidentally it is w = 0.5, half earth!) gives, as Wilson predicted, a stable and high human population (Fig 4). This makes sense mathematically, because the carrying capacity equation contains a term of the form x(1-x), which has a maximum at x = 0.5 where x is the fraction of the Earth dedicated to the ecosphere. But it also makes sense ecologically, because maximum sustainable food production is a trade-off between maximizing arable land and maximizing climate stability, the latter embodied in wild forests and arctic ice, and other buffers to change. A global climate awareness campaign might lead to such a balance.