Theoretical Physicists Say 90% Chance of Societal Collapse Within Several Decades

Deforestation and rampant resource use is likely to trigger the 'irreversible collapse' of human civilization unless we rapidly change course.
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Image: Pamela Guest

Two theoretical physicists specializing in complex systems conclude that global deforestation due to human activities is on track to trigger the “irreversible collapse” of human civilization within the next two to four decades. 

If we continue destroying and degrading the world’s forests, Earth will no longer be able to sustain a large human population, according to a peer-reviewed paper published this May in Nature Scientific Reports. They say that if the rate of deforestation continues, "all the forests would disappear approximately in 100–200 years.”


"Clearly it is unrealistic to imagine that the human society would start to be affected by the deforestation only when the last tree would be cut down," they write.  

This trajectory would make the collapse of human civilization take place much earlier due to the escalating impacts of deforestation on the planetary life-support systems necessary for human survival—including carbon storage, oxygen production, soil conservation, water cycle regulation, support for natural and human food systems, and homes for countless species.  

In the absence of these critical services, “it is highly unlikely to imagine the survival of many species, including ours, on Earth without [forests]” the study points out. “The progressive degradation of the environment due to deforestation would heavily affect human society and consequently the human collapse would start much earlier.” 

The paper is written by Dr Gerardo Aquino, a research associate at the Alan Turing Institute in London currently working on political, economic and cultural complex system modelling to predict conflicts; along with Professor Mauro Bologna of the Department of Electronic Engineering at the University of Tarapacá in Chile.  

Both scientists are career physicists. Aquino has previously conducted research at the Biological Physics Groups at Imperial College, the Max Planck Institute of Complex Systems and the Mathematical Biology group at the University of Surrey.


Their research models current rates of population growth and deforestation as a proxy for resource consumption, to calculate the chance of civilization avoiding catastrophic collapse.  

Point of no return

Before the development of human civilizations, the Earth was covered by 60 million square kilometres of forest. As deforestation has accelerated due to the human footprint on the planet, the new paper points out that there are now less than 40 million square kilometres of forest remaining. 

“Calculations show that, maintaining the actual rate of population growth and resource consumption, in particular forest consumption, we have a few decades left before an irreversible collapse of our civilization,” the paper concludes.

Tracking the current rate of population growth against the rate of deforestation, the authors found that “statistically the probability to survive without facing a catastrophic collapse, is very low.” Its best case scenario is that we have a less than 10 percent chance of avoiding collapse. The authors write: 

“In conclusion our model shows that a catastrophic collapse in human population, due to resource consumption, is the most likely scenario of the dynamical evolution based on current parameters…. we conclude from a statistical point of view that the probability that our civilization survives itself is less than 10 percent in the most optimistic scenario. Calculations show that, maintaining the actual rate of population growth and resource consumption, in particular forest consumption, we have a few decades left before an irreversible collapse of our civilization.” 


This verdict would seem to indicate that there is an over 90 percent probability of a collapse of industrial civilization, based specifically on assessing the impact of deforestation on the ‘carrying capacity’ of the planet—the capacity of the planet to support human life. 

The model developed by these scientists depicts human population growth reaching a maximum level that is undermined by the debilitation of forests. After this point, “a rapid disastrous collapse in population occurs before eventually reaching a low population steady state or total extinction… We call this point in time the ‘no-return point’ because if the deforestation rate is not changed before this time the human population will not be able to sustain itself and a disastrous collapse or even extinction will occur.”

Can technology save the day? 

The authors offer an intriguing techno-utopian twist to the study. They put forward the idea of building a Dyson Sphere, a hypothetical megastructure around our sun which absorbs the bulk of its solar energy and sends it back to earth. “Again to be precise, the Dyson sphere does not have to be taken literally, but rather as an energy value,” Dr Aquinos told me. The same energy output could be produced in any other manner, such as “nuclear fusion” for instance. 

In short, faced with the prospect of collapse, without changing our unsustainable levels of population growth and consumption the only other pathway to survival would be an unprecedented degree of technological development, the authors suggest. 


It helps to think about the Dyson Sphere in the context of the ‘Kardashev scale,’ a measure proposed by Soviet astronomer Nikolai Kardeshev in 1964 to assess the level of a civilization’s technological advancement based on the amount of energy it is able to harness.  

The Kardashev scale suggests that if a civilization can achieve the technological prowess necessary to fully harness the energy from its own star, this would allow it to transcend conventional resource limits.  

“The consumption of the natural resources, in particular the forests, is in competition with our technological level,” wrote Aquino and Bologna. Being theoretical physicists, much of the paper approaches these problems on a theoretical level, and parts of it are speculative—what would a society need to do to transcend resource limits, and what would such a society look like?

“Higher technological level leads to growing population and higher forest consumption… but also to a more effective use of resources. With higher technological level we can in principle develop technical solutions to avoid/prevent the ecological collapse of our planet or, as a last chance, to rebuild a civilization in extra-terrestrial space.”  

Of course, the authors acknowledge that our engineering capabilities are currently insufficient to make such powerful technology possible.  

So alongside their model of human-forest interactions, they compared it to a model of technological growth to determine whether we have a chance of developing such capabilities before ecological crisis triggers civilizational collapse. Unfortunately, not really. It’s in this specific context that they conclude we have a less than 10 percent chance of doing so and thereby averting collapse.  


The broader implication, the authors speculate, is that this predicament might explain why we haven’t been able to detect evidence of intelligent alien life elsewhere in the universe: the dynamics modelled here suggest that intelligent civilizations tend to crash and burn due to overconsumption of their planetary resources, long before innovating the capabilities necessary to become more advanced and enduring. 


Digging deeper into the paper raises a number of key issues.  

Focusing in on its model of human-forest interaction, the collapse implications are especially sobering.  

This is because the human-forest interaction model is based on “deterministically” running forward parameters for population growth and deforestation based on “current conditions.” 

The assumption is that these rates and conditions will simply continue at around the same level. When we do this sort of exercise, the model is not set-up to assess ‘what if’ probabilities: rather, it demonstrates what would happen on a very literal ‘business-as-usual’ scenario that takes current trends and extrapolates them forward in time. 

The verdict therefore seems quite stark: if we continue at the current rate of deforestation, population growth and resource consumption, collapse would appear unavoidable within the next two to four decades. 

The good news is that there is reason to believe that this worst-case scenario, although insightful in understanding the truly severe risks of our current trajectory, may not reflect more recent expectations about these trends.  


According to the 2020 State of the World’s Forests report published by the United Nations Food & Agricultural Organisation (FAO) jointly with the UN Environment Programme (UNEP), the rate of global deforestation has been declining over the last few decades.  

From the 1990s to the period between 2010 and 2020, the net loss of forest area decreased from 7.8 million hectares per year to 4.7 million hectares per year. One reason for this is that despite ongoing deforestation, new forests are also being established, both naturally and through deliberate planning.  

But the rate of deforestation also appears to have declined in real-terms. In the 1990s, the UN report states that the rate of deforestation was around 16 million hectares per year. Between 2015 and 2020, this had declined to an estimated 10 million hectares per year.  

Yet this does not justify complacency. In absolute terms, the UN report shows that global forest area still decreased overall by a colossal 178 million hectares between 1990 and 2020, an area about the size of Libya.  

We are also at grave risk of reversing this modest slowdown. The latest data produced from the World Resources Institute’s Global Forest Watch project confirms that primary forest loss was 2.8 percent higher in 2019 than the previous year, indicating that we are about to see a re-acceleration in the rate of forest loss. 

Similarly, projected rates of population growth are likely to be lower than previously anticipated. A new set of forecasts published by The Lancet suggests that world population growth may begin to start shrinking after mid-century due to declining fertility rates, contrary to earlier major projections.


Unfortunately, the time-scale for these changes could well be too slow to substantially alter the implications of the new Nature Scientific Reports model. As the study authors point out, “it is hard to imagine, in absence of very strong collective efforts, big changes of these parameters to occur in such time scale”—notwithstanding the possibility of “fluctuations around these trends.” 

But these slowdowns indicate that averting such dangerous exponential growth trends could be feasible, especially with a more intentional and targeted approach. 

The alternative: Caring about the Earth

Another way to avert collapse, the authors contend, is fundamental civilizational transformation.  

The underlying driver of the current collapse trajectory is that “consumption of the planetary resources may be not perceived as strongly as a mortal danger for the human civilization”, because it is “driven by Economy”. Such a civilization “privileges the interest of its components with less or no concern for the whole ecosystem that hosts them.”  

In the absence of rapidly building a Dyson Sphere, the physicists suggest that to escape our collapse trajectory “we may have to redefine a different model of society… that in some way privileges the interest of the ecosystem above the individual interest of its components, but eventually in accordance with the overall communal interest.”

So the most effective way to increase our chances of survival is to shift focus from extreme self-interest to a sense of stewardship for each other, other species, and the ecosystems in which we find ourselves. 

In other words, to avert collapse we either need to become ET, or spearhead a civilizational paradigm shift. Which is more probable?  

Ultimately, that’s up to us. If this study is remotely accurate, humanity has perhaps only a few more decades left to decide.