Limits to growth - the 30-year update, is the successor to the popular 1972 report Limits to growth. It was created by the Club of Rome, an organization consisting of one hundred members selected from governments, UN administrators, high-level politicians, diplomats, scientists, economists and business leaders.
It adresses issues concerning our growing resource consumption and population. The findings presented by the book are more relevant than ever before which is the reason why I want to introduce it here.
The first thing we need to understand is the concept of overshoot. Overshoot in this context means we exceed some kind of limit and it may appear in all different forms. Examples include drinking more alcohol than the body can metabolize, driving too fast on an icy road or turning the hot water faucet too far. All of these things end in a mostly unpleasant result - but most often not immediately. This is where delay comes into play.
The first condition that needs to be fulfilled is a rapid rate of growth of the usage of the sources and sinks. In our world, examples can be found when taking a look at economies and their pursue of growth. We see news talking about a 3% binannual growth of the market which is almost exclusively tied to increased resource consumption as well. Exponential growth is what makes overshoot so insidious - most people have no intuition of its implications and dangers, as we’ve seen in the ongoing pandemic.
Another thing that’s necessary for overshoot to occur is a limit to overshoot. In the context of our planet, these limits are divided into sinks and sources. Sinks refer to the capacity to absorb pollutants and waste like nitrous oxide while sources refer to things like mineral oil, copper, or, more abstractly, the capacity to generate usable energy.
+-------+ +-------+ +-----+
|sources| --> |economy| --> |sinks|
+-------+ +-------+ +-----+The rate at which resources flow from the sources into our economy (with lots of further flow paths) and then finally into the sinks is referred to as physical throughput.
We may spend time in overshoot without actually encuring apparent damage. The damage becomes visible only after a certain amount of time due to the nature of the overshoot - when drinking too much, the alcohol first needs to be metabolized down to products that actually hurt your body. In the same manner, pollutants emitted into the environment take a certain amount of time to reach a place in which they can become harmful. This is known as delay. Delay not only occurs on the perception side, but also when trying to take action. It takes time between a policy to replace old, inefficient boilers with newer, more efficient ones. Large-scale measures taken against pollution might take decades to fully become effective.
To summarize: for overshoot to occur, we need
Before we come to the model and its conclusions, let’s take a look at some of the examples given in the book. A good example is the story of the ozone hole and of agricultural land.
In the mid-to-late twentieth century, chlorofluorocarbons, or CFCs for short, were used by a lot of products like refrigerators or spray cans. At the same time, scientists noticed unusually low readings of ozone levels in the upper atmosphere. Ozone is a molecule made up of three oxygen atoms that is vital in blocking harmful UV radiation. In regions with even one percent less ozone, cases of skin cancer went up measurably. CFCs contain chlorine which destroys ozone once it arrives in the upper atmosphere, but the chlorine itself is not consumed. A single chlorine molecule can thus destroy multiple hundreds of thousands of ozone molecules before it finally stops.
The good news is we’ve created laws around the world that prohibit large-scale production and usage of CFCs so the ozone layer will slowly regenerate over the next coming decades. But this process took a lot of effort - the first report of CFCs being harmful to the ozone layer appeared in 1976, but the Montreal treaty to phase out CFCs appeared 11 years later, in 1987. A delay of 11 years, not including the actual time it took for companies to switch off CFC production.
The ozone layer will heal completely, but its depletion has caused and still will cause hundreds of thousands of cases of cataracts and skin cancer.
We lose around three million hectares of agricultural land each year due to soil degradation and erosion. Yes, three million hectares, the size of Belgium. Farmland can be regenerated by special agricultural practices, but lots of land is lost forever and the rate at which land is lost is itself getting bigger.
The thing with overshoot is that after we’ve spent some time over the limit, the actual limit itself decreases. This means in practice that we cannot return to the limit we had before - by exploiting resources, we decrease the amount of resources we can use sustainably in the long run. By staying in overshoot longer, we degrade the resource base even more and make it unusable in the future.
The concept of sinks, sources and resource flows are rather abstract and need therefore be backed by concrete models to allow us to make predictions. The model used by the research team of LTG is called World3 and aims at modeling the most important interactions between
These five indicators are called the state of the world. Interactions between them are modeled quite detailed, but still reside on a high layer of abstraction. The model does not concern itself with different geographic regions or different kinds of foods or discriminates between different kinds of industrial capital. Pollution for example is only divided into short-term and long-term.
An example of the different interactions might be an increasing population which leads to further food production. This increased food production uses up a larger amount of the industrial output. Another core concept are feedback loops. They are divided into positive and negative feedback loops. The main feedback loops governing the model are population and industrial output. They each come in positive and negative variants.
Negative and positive feedback loops often balance each other out, but their strength depends on lots of other factors in the system.
Given a set of starting conditions, the model can create predictions for the development in the twenty-first century. The state of the world is graphed alongside two other categories.
Because the model is based on many assumptions and simplifications, it is not meant to be used to make exact predictions - it cannot give the exact life expectancy in 2067 or human welfare index in 2092. The thing it is good at is revealing certain trends with reasonable certainty.
LTG presents ten different scenarios, each with different premises and outcomes. The two main outcomes are collapse and sustainability. Collapse is characterized by a sudden decline of world population and industrial activity as well as human welfare.
The other scenarios lie somewhere in between, but most produce collapse as a result.
The message is clear - we need to reduce our physical throughputs and protect sources and sinks to stop the current overshoot. If we don’t reduce them willingly through policies, nature reduces them for us, with potentially catastrophic consequences for our society. But a sustainable future in which everyone can live a good life is possible. Lots of opportunities have already passed and we have let decisions slip by that could have allowed us an even better sustainable life, but we still have time to act. Decisive and quick changes are necessary in order to achieve this. We need to
Herman Daly has proposed three conditions a materially and energetically sustainable society must meet:
Lots of the underlying commitment to growth comes from trying to solve problems in mainly three areas:
Growth isn’t solving these problems at all or only inefficiently.
Things we should do instead are
It is our job to find solutions to these problems which don’t rely on endless physical growth.
A sustainable future is possible and desirable and will bring with it a new age to humankind just like the agricultural and industrial revolution did. Sustainability does not mean standstill. It means carefully assessing when and where we need to use resources and stopping the instrumentalization of our environment as a means to produce an ever-increasing amount of goods.
The core issue raised by the report is one I complete agree with. Endless physical, exponential growth in a finite world with finite resources is impossible as we will reach a limit eventually. This is not something far in the future, as we are already hitting hard limits in certain areas like a lack of groundwater or arable land. We are also noticing the effects our waste products have on the environment. By emitting an ever-increasing amount of carbon dioxide, we accelerate climate change even more and exacerbate already existing problems like flooding and droughts.
The concept of delay is also quite easy to confirm in the real world. Even if we were to completely stop emitting CO2 right now, already emitted CO2 in the atmosphere would warm the planet for the coming centuries nonetheless. We need to act now because our actions take a long time to show effect and the longer we wait, the more opportunities we miss. We will only take action once we reach the point where droughts and floods hit us hard, where we are measurably impacted by microplastics traveling up our foodchain etc. But we need to act proactively, we need to extend the planning horizon. If we don’t, lots of industrial output will disappear or be locked in mitigating climate damage.
Are we too short-sighted to prevent collapse? This is a hard question to answer. We will at one point or another need to transition to a net-zero society, that’s for sure. I think we will continue the pursuit of physical growth and ever-increasing consumption at least for the next coming decades. We hear of countries being swept away by rising sea levels and hundreds of thousands of people dying due to multiple consecutive years of drought, but still miss our goals of the Paris climate agreement. We probably won’t take action until the consequences are dire enough for our own lifestyle to be in danger. Once we reach this point, the controlled transition to a sustainable society becomes impossible. Markets will crash, prices will soar and food will become more scarce, even for us. Millions of people will flee from their countries and increasing competition for fresh water supply instigates conflict and wars. After a period of hardship, but not necessary collapse, we will create new, international treaties to slowly transition into a true sustainable society, but not without a sharp decline in human welfare beforehand. Reading the IPCC reports only seem to validate this view even more.
You might have a more optimistic outlook of the future. Maybe the free market will come up with some form of super-technology or a new generation of leaders will take matters into their own hand before it is too late. Whatever the future may bring, being prepared for the worst is not a bad idea.
I recommend reading LTG for yourself because I skipped on many important pieces of information. The authors paint a more complete picture and while some parts might be boring, they are essential to understand the whole message. The book has been criticized for using wrongful premises or being overly sensitive to a few input variables, but I think the overall message still applies. Like the authors already said - World3 is just a model which cannot answer everything. The right questions must be asked and the answers must be viewed with skepticism, but the same must be done when people talk about being able to do business as usual. Get as much information as you want and then find your own conclusion. Who knows, maybe you are the one to correctly predict the future.