Introduction

Nothing in biology makes sense except in the light of evolution. Theodosius Dobzhansky Nothing in evolutionary biology makes sense except in the light of ecology. Grant & Grant

As a naturalist, I’ve often wondered about the future of nature. On the one hand, it looks very bleak. The news is full of stories about the negative impact humans are having on the environment: pollution, deforestation, invasives, climate change, and our relentlessly increasing ecological footprint. So many species are going extinct as a result of our presence that we can now speak of a sixth global mass extinction occurring.

On the other hand, we are becoming increasingly aware of the impact we are having, and of the value of the ecosystem services that we are losing, and we are doing something about it. Thanks to environmental legislation the air and water is cleaner now in many places in the world. Not only are many species now protected, but also many natural areas. We’ve gone from the first protected areas in the nineteenth century, Yosemite Valley and Yellowstone National Park, to over 100,000 protected areas worldwide covering 12% of Earth’s land surface. Much research and effort continues to go into understanding habitats and how to restore them. In general, there seems to be not only an increasing awareness and appreciation of nature, but also an increasing willingness to make some sacrifices in order to preserve nature. Another trend that seems to be working in nature’s favor is the demographic transition. In many areas, human population growth is slowing, and in some areas it’s even reversing, taking some pressure off the environment.

The big question is, Which of these trends is going to win out in the long run? Most environmentalists continue to preach doom and gloom. There is even a widespread belief that the loss of ecosystem services will eventually lead to the collapse of civilization, and perhaps even to the extinction of humans. The Utopian view, on the other hand, is popular especially among engineers, conservatives, and many physical scientists. They believe that technological progress will continue to improve the standard of living for all, and spread not just wealth, but also the demographic transition to all people in the world.  With everyone fed and population growth under control, we will be able to live sustainably and in harmony with nature – indefinitely.

Is it possible to decide which scenario is correct? Of course it’s hard to predict the future, especially for a system as complex as the entire biosphere. But it is possible to make scientifically informed predictions if they are based on the laws of nature. For example, long-term weather prediction does not make any sense because weather systems are too nonlinear, even chaotic, but modeling the climate far into the future does make sense.

Logistic population growth curveOne might argue that the laws of nature only apply to non-living systems, but I disagree. I believe there are biological laws of nature. Interesting examples in this context would be exponential growth and limits to growth of populations (Dodds 2009). As long as there is an abundance of required resources and a lack of limiting factors such as disease or predation, a population will always grow exponentially. Of course, eventually there will be a limiting factor, which means that in the long run, a population will grow until it reaches its environment’s carrying capacity.

When it comes to understanding how humans fit in with the rest of nature, it seems to me that most people simply adopt the scenario that suits their personality or political beliefs. But I believe the only way to really understand the human-nature relationship is through a rigorous scientific analysis, which implies that it’s based on the laws of nature.

In order to better decide exactly how to perform this kind of scientific analysis, let me rephrase the situation a bit. The biosphere consists of millions of species of organisms that have all evolved to be part of a coevolutionary network. This paradigm has persisted since life first evolved 3.5 billion years ago, despite several mass extinctions and evolutionary transitions. In the struggle for survival, some species don’t do so well and eventually go extinct. Other species do better and manage to become more dominant; however, there seems to be a limit as to how dominant a species can become. The more dominant a species is, the bigger a target it becomes for predators and parasites. Eventually, competitors catch up, further limiting its dominance. Any species that finds a way around all these limitations to its continued increase in dominance has hit the evolutionary jackpot. Even the most awesome of all terrestrial predators that ever existed, Tyrannosaurus rex, couldn’t pull it off. It appears that the bar is set so high that not once – as far as we know – in the 3.5 billion year history of life has a species managed to free itself from the constraints of the coevolutionary network that it evolved in. Not once, that is, until about 60,000 years ago, when a small group of perhaps a few hundred humans – having barely escaped extinction – left its homeland in Africa and went on to spread over the entire planet, becoming the first globally dominant species. As a result we are now not only witnessing a mass extinction event, but also a major evolutionary transition.

In 2008 a proposal was made to name the current epoch the Anthropocene (Zalasiewicz 2008), in recognition of the enormity of the human impact on the planet’s ecosystems, such as loss of biodiversity, agriculture, increase in atmospheric CO2 content, changes in soil formation, etc. The justification for redefining the Holocene as the Anthropocene is entirely descriptive. No attempt is made in explaining why humans are having such an impact. This is what the Darwinian demon theory does. It explains how we’ve become such a dominant species, and what it means for the future of life on Earth.

This reframing of the problem in biological terms makes it clear that understanding the human-nature relationship is equivalent to figuring out how one species could become ecologically so dominant. The usual starting point in ecology when trying to understand a species is to ask what its ecological niche is. Back in 2006, when I first tried to answer this question, the only answer I could find is that we are hunter-gatherers. It was obvious to me that this was the wrong answer, since I have never met any hunter-gatherers, and the few populations of hunter-gatherers known to still exist aren’t doing so well. But it didn’t take me long to come up with a better answer, based on what I already knew about ecology and human nature, and the result is the Darwinian demon theory of human ecological dominance. In addition to evolutionary ecology, I also made use of gene-culture coevolution, evolutionary psychology, human behavioral ecology, anthropology, environmental science, theory of science, and economics.

Trying to answer the simple question – What is the human ecological niche? – resulted in a theory that turns out to have a surprisingly wide scope, capable of answering, or at least shedding light on, the following questions:

  • Is it possible for humans to live sustainably?
  • Will the value of ecosystem services help us to preserve nature in the long run?
  • Why are humans so dominant?
  • How much more dominant will we become?
  • What impact will our dominance have on the future of the biosphere?
  • Can we stop the current mass extinction?
  • Will we ever get human population growth under control?
  • Will there be a Malthusian catastrophe?
  • What really sets us apart from other species?
  • What is the future of life?
  • What is the future of the human species?
  • Why has the SETI project not had any success?

The goal of this blog is to introduce the Darwinian demon theory of human dominance, and use it as a scientific foundation to answer all theses questions. Regarding the two extreme scenarios I presented at the beginning, the theory says that neither of them are realistic, nor is any scenario in between. What it predicts is something completely different from anything anyone – as far as I know – has ever proposed, something that even I found quite surprising.

In case it wasn’t already obvious, I would like to emphasize that I am only interested in exploring these questions from a purely scientific point of view.  This blog is not about how to solve the population problem; it’s about exploring what life might be like for us at Earth’s carrying capacity for humans. It’s not about how to live more sustainably; it’s about understanding what the word sustainability really means. It’s not about how we can change the world for the better; it’s about gaining a better understanding of how we are changing the world.

References

Dodds, W. K. (2009). Laws, Theories, and Patterns in Ecology. Berkeley and Los Angeles: University of California Press.

Zalasiewicz, J. et al. (2008). “Are we now living in the Anthropocene?”. GSA Today 18 (2): 4–8.

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How one species is transforming the biosphere

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