Humanity has a now or never opportunity to change direction. Will it consciously let go of growth as its goal and shift priorities towards resource efficiency, pollution abatement, and health and education services? We have a chance to redesign society away from material consumption to human and ecological well-being.

Gaya

<p>My research went viral last summer. I found out via a friend’s text, jokingly accusing me of “announcing the end of the world.” For several days, headlines on major US news pages declared that my research proved we are on the brink of collapse. A few days later, UK pages touted the same headlines. Then I saw my name popping up in languages I do not know, from Swedish, to Greek, to Chinese, to Sinhala.</p>
<p>It took me a bit by surprise. My research had been published months earlier, in November 2020. Also, it was a data comparison of a model from a book that was almost half a century old. Apart from the headlines being a simplistic version of my research’ message, they also gave the impression that the possibility of societal collapse suddenly had been revealed. But this warning was a key message of <a href="https://www.clubofrome.org/ltg50/"><em>The</em></a> <a href="https://www.clubofrome.org/ltg50/"><em>Limits to Growth</em></a> (LtG) book, which the authors Meadows, Meadows, Randers &amp; Behrens, published back in 1972. In LtG, commissioned by the Club of Rome, the authors identified society’s relentless pursuit of growth not as the solution to, but the cause of, so many of the environmental and social crises that plague humanity still today. Their analysis was based on a global model called World3. The authors created different scenarios by varying World3’s underlying assumptions. This scenario analysis helped them study global dynamics between variables including industrial output, resources, pollution, and living standards. In my research, I compared four LtG scenarios against a few decades of empirical data. Details about the scenarios methods and results, can be found in my article in Yale’s <em>Journal of Industrial Ecology</em>. An easier read with the gist of my findings was also published on the <a href="https://www.clubofrome.org/blog-post/herrington-world-model/?fbclid=IwAR34J-QE4mDCelAawQtHAP24B7IPDLFB_lmT_qLu-5_SKgy9fpWI15-FcY0">Club of Rome website</a>. Here, I’ll just share my conclusions, illustrated by a graph of the variable people might be most concerned with: living standards (Figure 1). This graph is from my upcoming book <em>Five Insights for Avoiding Global Collapse</em>, soon available online under Creative Commons, which contains further research analysis and 2022 data update of my comparison.</p>
<img src="https://illuminem.b-cdn.net/articlebody/14c25ac5559a0b3ffcdc1ce96f162c866feac5cc.png" alt="Figure 1: Empirical data plotted against four World3 scenarios. The dashed purple line is the empirical data, sourced from the United Nation’s Human Development Index.">
<p>I found an overall close alignment of empirical data with the scenarios, for now, because they only diverge significantly after 2020. This accuracy decades into the future gives reason to take the World3 dynamics seriously. If we do that, we unfortunately must conclude that the future holds risks of declines in welfare, among other things, and some of these declines are indeed steep enough to constitute a collapse. The scenario indicated with “SW” shows no collapse and the highest living standards. However, empirical data aligned least closely to SW. </p>
<p>I interpret all this as humanity having a now or never opportunity to change direction. Contrary to what my friend texted me, I did not predict the end of the world, just like LtG didn’t at the time; I noticed warning signals and voiced a call to action. Empirical data are not far from SW yet, and humankind can determine where future data points fall. How? Well, there is one key difference between SW and the other scenarios: in SW, humanity consciously lets go of growth as its goal. Under SW assumptions, society shifts priorities away from industrial output growth towards resource efficiency, pollution abatement, and health and education services. We can do that in the real world too. </p>
<p>Will we? Before you answer that question in your head, let’s frame it properly. Because this is not about whether we want to avoid collapse; it’s whether we want better. SW represents a redesign of society away from material consumption, around human and ecological well-being. Yes, that would take a lot of effort. But we’d also be working on healing society, towards a future of thriving. Does that sound to you like something worth putting in work for? </p>
<p>If so: good news. At LtG’s 50-year anniversary, the Club of Rome will publish a follow-up called <a href="https://www.earth4all.life/"><em>Earth for All: A plan for global wellbeing on a healthy planet</em></a>. This new book describes how to launch society into a sustainability transformation. The book is still realistic in that it foretells that what we do in the next decade will determine our livings standards for the rest of this century. But even more, it’s a vision for a better world. We need to act fast, yes, but we are not out of time yet to turn society around. And not only are we capable of making this change; we are yearning for it. A world for all where life can flourish indefinitely will be so much more than just a society that avoided societal collapse. It will have been so much worth the effort.</p>
<p><em>This article is also published by the <a href="https://www.clubofrome.org/blog-post/herrington-ltg50/">Club of Rome</a>. Energy Voices is a democratic space presenting the thoughts and opinions of leading Energy &amp; Sustainability writers, their opinions do not necessarily represent those of illuminem.</em></p>


What a 50-year-old world model tells us about a way forward today

In the 1972 bestselling book Limits to Growth, the authors concluded that if humanity kept pursuing economic growth without regard for environmental costs, global society would experience sharp declines in available food, standards of living, and ultimately the human population, within the 21st century. This article is a follow-up research and it finds that the predictions were right. Now, only the future will tell which way we follow.

<p>In the 1972 bestselling book <a href="https://www.clubofrome.org/publication/the-limits-to-growth/"><em>Limits to Growth</em></a> (LtG), the authors (Meadows, Meadows, Randers &amp; Behrens) concluded that if humanity kept pursuing economic growth without regard for environmental costs, global society would experience sharp declines in available food, standards of living, and ultimately the human population, within the 21st century.</p>
<p>The LtG authors used a dynamic systems model, World3, to study key interactions between global variables for population, fertility, mortality, industrial output per capita (p.c.), food p.c., services p.c., nonrenewable resources, and pollution. World3 is based on the work of Forrester (e.g, 1971; 1975), at the time a professor at MIT and the founder of <a href="https://mitsloan.mit.edu/faculty/academic-groups/system-dynamics/about-us">system dynamics</a>: a modelling approach for the interactions between parts of a system, which often produce non-linear behaviour like delays, feedback loops, and exponential growth or decline.</p>
<p>The LtG team generated different scenarios for global developments with World3 by varying assumptions about technological innovation and adoption, amounts of nonrenewable resources, and societal priorities. Some scenarios ended in sharp declines, i.e., a collapse. Collapse in this context did not mean that humankind would cease to exist altogether, just that next generations would be significantly worse off than previous ones. Not all scenarios displayed steep declines; the LtG team identified a set of assumptions that produced a “stabilised world” (SW) scenario in which collapse was avoided and welfare remained high.</p>
<img src="https://illuminem.b-cdn.net/articlebody/b452778089177b5eaf942d73da31c4fa111e06a0.png" alt="Figure 1. BAU (left) and SW (right) scenarios from the World3 model">
<p>However, <a href="https://www.ethz.ch/content/dam/ethz/special-interest/usys/ites/ecosystem-management-dam/documents/EducationDOC/Readings_DOC/Turner_2012_GAIA_LimitsToGrowth.pdf">independent data comparisons</a> since then indicated that the world was still following the “business as usual” (BAU) scenario. This BAU scenario showed a halt in the hitherto continuous increase in global welfare levels around the year 2020 (yes, that’s last year), and collapse setting in around 2030. The <a href="http://sustainable.unimelb.edu.au/sites/default/files/docs/MSSI-ResearchPaper-4_Turner_2014.pdf">last data comparison</a> dated from 2014. That is, until last year when I did mine.</p>
<h1>What I Did</h1>
<p>Given the unappealing prospect of societal collapse, I decided to conduct a quantitative comparison between World3 scenarios and empirical data available in 2019. This research was part of my thesis for a Master’s in Sustainability at Harvard University, which I finalized last month. Has humanity done better over recent years, or are we still following the BAU scenario?</p>
<h2>Four World3 scenarios</h2>
<p>The LtG authors published three books between 1972 and 2004, in each of which they studied interactions between the global variables of the World3 model. World3 was updated for each book, so the scenarios varied slightly to moderately in each publication. Previous data comparisons were conducted on the 1972 version of World3. I decided to work with the last World3 version from the LtG book published in 2004 (Meadows, Meadows, &amp; Randers). I chose four scenarios to compare empirical data against: the aforementioned BAU and SW, and the “comprehensive technology” (CT), and “business as usual 2” (BAU2). (Also called scenarios 1, 2, 6, and 9 in the book.)</p>
<p>The four scenarios address different “stories”. The BAU scenario was based solely on historic averages without any assumptions. As mentioned, this “business as usual” scenario ends in collapse (Figure 1 and Figure 2). In SW, humanity changes priorities away from material consumption and industrial growth towards health and education services, as well as pollution abatement and resource efficiency technologies. This avoids collapse and leaves humanity with the highest levels of welfare (Figure 1 and Figure 2).</p>
<img src="https://illuminem.b-cdn.net/articlebody/cf9053e83ee7b14b35c8bec1a1fa101c66796ab1.png" alt="Figure 2. Human welfare and ecological footprint for BAU (left) and SW (right)">
<p>CT represents the technologist’s belief in humanity’s ability to innovate out of environmental constraints. It assumes unprecedented technological innovation in a world that otherwise does not change its priorities much. The new technologies do in fact help avoid an outright collapse. However, CT still depicts some declines (Figure 3) because the technology costs become so high that not enough resources are left for agricultural production and health and education services.</p>
<p>BAU2 assumes double the resources as in BAU. More abundant resources do not avoid a collapse; its cause merely changes from a resource scarcity crisis to a pollution one. With the resource constraint relaxed, incentives to innovate and/or change societal priorities are reduced, so business as usual goes on for longer. This creates so much pollution that agricultural output and human health plummet after some breakpoint (Figure 3). BAU2 essentially tells the story of ecosystem breakdown from accumulated pollution, including from greenhouse gasses (i.e., climate change).</p>
<img src="https://illuminem.b-cdn.net/articlebody/31dac7cd4890786881431fcf67f4fd2efac68216.png" alt="Figure 3. CT (left) and BAU2 (right) scenarios from the World3 model">
<p>I chose BAU, BAU2, CT, and SW because together they form a comprehensive set. The assumptions underlying each scenario span a range in technological, social, or resource conditions. Additionally, the cause of decline, varying from a temporary dip to societal collapse, differs for each scenario.</p>
<img src="https://illuminem.b-cdn.net/articlebody/31aeaeaa5a3a536528164fbcfc743fb96b0ab85f.png" alt="undefined">
<h1>Data</h1>
<p>I collected data for real-world indicators of the World3 variables population, fertility, mortality, pollution, industrial output, food, services, non-renewable natural resources, human welfare, and ecological footprint. This data came from academia, (non-)government agencies, United Nations entities, and the World Bank. A full description of the data sources can be found in my thesis on the <a href="https://dash.harvard.edu/handle/1/37364868">Harvard website</a>.</p>
<p>I plotted the empirical data together with the variable in each of the four scenarios made with the latest version of World3. These plots gave good impressions of the fit, but I also used statistical measures (a normalised root mean square error, and a combination of the value difference and difference in rate of change) to validate what I observed in the graphs.</p>
<h1>What I Found</h1>
<p>The graphs for every variable can be found in my thesis, but most show an image similar to the below one (Figure 4): an overall close alignment of empirical data with each of the four scenarios, least closely with SW and most closely with BAU2 and CT.</p>
<img src="https://illuminem.b-cdn.net/articlebody/c1108b58077a917f1e9f9feafc8044f57ff8f1eb.png" alt="Figure 4. Empirical data for birth rate (births per 1,000 people) and the variable for each scenario">
<h2>World3 was pretty good</h2>
<p>The overall close alignment of empirical data with each of the four scenarios is a testament to the accuracy of World3. It received a lot of <a href="https://www.resilience.org/stories/2011-09-15/cassandras-curse-how-limits-growth-was-demonized/">criticism</a> at the time, most of it from people misunderstanding the book’s message or the new modelling technique (i.e., system dynamics modelling). But as someone with a Bachelor’s degree in Econometrics and years of work experience in finance and strategic consultancy, I could not tell you another model that has forecast this accurately several decades into the future.</p>
<h1>Break from previous research</h1>
<p>As mentioned, SW was followed least closely. Both BAU2 and CT aligned closest, and BAU scored in between. Thus, unlike in previous research, BAU is no longer the scenario that’s followed closest.</p>
<p>I should note that for several variables the scenarios only diverge significantly after 2020 (as is the case in the above graph, Figure 4). This is especially so for BAU2 and CT, which is why it was not possible to differentiate between them. It’s thus unclear whether a future decline in human welfare can be expected to be moderate as in CT, or sharp like in BAU2 (see Figure 5). Both scenarios however do indicate society will see a halt in industrial, agricultural, and welfare growth in the near to medium term.</p>
<img src="https://illuminem.b-cdn.net/articlebody/6006ce816554e676aac1e98b14017c7265ac21b2.png" alt="Figure 5. Human welfare and ecological footprint for CT (left) and BAU2 (right)">
<h2>We’re probably not on a path to a stable world</h2>
<p>An update of this comparison in another few years might be able to identify one specific closest fit to empirical data. Without major changes in societal priorities, this is unlikely to be the scenario showing a sustainable path; the SW scenario, in which a decline in human welfare within this century is minimized (Figure 2), aligned with the data the least.</p>
<h1>What It Means</h1>
<p>The BAU not being the closest fit scenario does not mean that societal collapse can be ruled out. The scenario that depicts the smallest declines, SW, is also the one that aligned least closely with empirical data. Furthermore, one of the best fit scenarios, BAU2, shows a collapse pattern. The other best fit scenario however, CT, shows only a moderate decline. Both scenarios show a slowdown in industrial and agricultural output. My research results at this point thus indicate that <strong>we can expect a halt in economic growth within the next two decades</strong>, whether we consider that a good thing or not. (Indeed, as the informed reader knows, <a href="https://www.nytimes.com/2019/06/18/business/economy/global-economy-trade-war.html">economists</a> and organizations like the <a href="https://www.economist.com/graphic-detail/2019/04/09/the-world-economy-is-slowing-down">IMF</a> have been pointing out recently that we’re seeing a “<a href="https://www.nasdaq.com/articles/new-imf-chief-georgieva-warns-of-synchronized-slowdown-in-global-growth-2019-10-08">synchronized slowdown in global growth</a>“.) The strongest conclusion that can be drawn from my research therefore, is that <strong>humanity is on a path to having limits to growth imposed on itself</strong> rather than consciously choosing its own. However, my research results also leave open whether the subsequent declines in industrial and agricultural output will lead to sharp declines in population and welfare levels.</p>
<img src="https://illuminem.b-cdn.net/articlebody/4aca16ce62f56644024d04063f6216d8a7ee050e.png" alt="Figure 6. Empirical data plotted against human welfare variables for all four scenarios">
<h2>“So… Good chance we’ll be fine then?”</h2>
<p>If you’re thinking that we can bet humanity is following the CT scenario and we’ll basically be fine with only a temporary dip in welfare levels around 2050, you should know that the assumptions underlying CT are highly optimistic given historic figures. But I intentionally avoid delving into the details here of why I think the CT scenario is unrealistic, because it would obscure the question we really should be asking: do we want to be following the CT scenario in the first place?</p>
<p>Why would we use our innovative powers to invent robot pollinators to replace the bees, if we also have the choice to invent agricultural practices that do not have the side effect of insecticide? Why use drones to plant new trees, when we could also restructure our economy so that existing forests are not cut and burned down? Now that humanity has attained global reach and unprecedented power to shape its destiny, limits to growth force upon us the question: who do we want to be and what world do we want to live in?</p>
<h1>What scenario do we want to follow?</h1>
<p>We can choose different societal priorities for other reasons than looming collapse. Moreover, the possibility that collapse will not happen does not mean that humanity should not choose a more sustainable path. The LtG graphs show how society would be more stable in the SW scenario, but not how much more its citizens and their natural surroundings would be thriving. We don’t have to settle for CT as a best-case scenario.</p>
<p>The close alignment to empirical data and the fact that the scenarios have not diverged much yet, together form a call to action. Hidden behind a seemingly ambiguous outcome of two best fit scenarios that marginally align closer than the other two, hails the message that it’s not yet too late for humankind to change course and alter the trajectory of future data points. We have another choice. Although SW tracks least closely, a deliberate trajectory change is still possible. That window of opportunity is closing fast.</p>
<p><em>Energy Voices is a democratic space presenting the thoughts and opinions of leading Energy &amp; Sustainability writers, their opinions do not necessarily represent those of illuminem.</em></p>


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Gaya Herrington

Gaya Herrington

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