Mutualistic Cities, Chapter Three:
The Lightbulb at the End of Time, Part II

“Cities are parasitic organisms, using the raw materials of the ‘host Earth System’ without providing anything in return, and indeed harming the host. From such a negative relationship – can a mutualistic relationship evolve?”

'Mushroom coral (Fungia scutaria). Northwest Hawaiian Islands. September, 2004.’ Image by Dr. Dwayne Meadows, NOAA/NMFS/OPR. Sourced via Flickr Commons.

In the second chapter of Mutualistic Cities, Killian Quigley considered what mutualism means, and how thinking mutualistically may necessitate a radical shift in consciousness. In Chapter Three, Mark and Jan encourage us to look for the future of urbanism in places beyond the so-called West. They also clarify the special risks climate change poses for growing cities, and propose a plan for working toward “mutually beneficial” relations between urban centres and the Earth.  

The Need for Mutualism

Mutualistic change must occur quickly, if urban areas grow to be the colossi predicted by the end of the 21st century. Then, some cities will exceed 80 million inhabitants. These won’t be the rain-soaked cityscapes of some near-future Blade-running Los Angeles, but will, more likely, be akin to the giant cities of Africa and Asia. Rethink what you believe a megacity to be. Kinshasa, in the Democratic Republic of the Congo, is already the largest French-speaking city in the world, surpassing Paris in size, and is predicted to have over 83 million inhabitants in 2100, or more than the current population of the DRC (at nearly 79 million). Another African city, Lagos, Nigeria, will potentially be the biggest in the world, with over 88 million inhabitants in 2100.1 By 2100, 70 cities might exceed 10 million inhabitants. In this world, individual cities will become huge consumers of energy, and so must evolve a mutualistic relationship with the resources of the Earth System that sustain them.

Will Future Cities be Mutualistic or Parasitic?

Cities utilize the resources of the Earth System, including the biosphere for food and energy and the lithosphere for energy and building materials (to make and power those light bulbs, and much else). Cities also use the atmosphere for respiration and as a dump for pollutants, as well as the hydrosphere, which is also used as a dump for pollutants – especially for the excess carbon dioxide from industrial processes, dissolved into acidifying oceans, and those indispensable plastics we all too easily throw away. Conceived like this, cities are parasitic organisms, using the raw materials of the ‘host Earth System’ without providing anything in return, and indeed harming the host. From such a negative relationship – for at least some of the non-human components of the Earth System – can a mutualistic relationship evolve,2 one that benefits both city and its host? And if it doesn’t so evolve, what might happen?

Pebble Technofossil: The imprint of a bottle top in a sedimentary rock. Perhaps imprints like this will be part of the fossil traces of humans in the future. Image by Jan Zalasiewicz.

It’s perhaps easier to answer the second question first, by observing that a parasitic relationship is not sustainable. The parasite damages or kills the host. The parasite scenario is one where human agency fails, where agency is unable to foresee and plan a response to a changing environment caused by humans. Here, negative feedback mechanisms eventually kick in to curtail city development. For example, there may be 1.4 billion people living within the ‘low elevation coastal zone’ by 2060, with China, India, Bangladesh, Indonesia and Vietnam being the five countries with the greatest share of population in this zone.3 All of these countries have been predicted to be ‘top 30’ world economies in 2050.4 But if sea level rises by just a few metres as a result of climate change, large parts of coastal, low-lying cities – like Jakarta with its 20 million people – will become uninhabitable. Then, energy consumption would be curtailed by natural feedbacks operating beyond the capabilities of humans. That is a ‘forced’ way to reduce energy consumption, but very likely not a good way for the wellbeing – and indeed the continued existence – of many millions of people.

Toward Mutual Benefit

Of course, it does not have to be this way. Humans can develop a relationship with the rest of the Earth System that is mutually beneficial. Such relationships are widespread in nature, such as the coral-dinoflagellate relationship in the oceans, where the tiny dinoflagellates provide the coral with the products of photosynthesis, and in return the corals provide carbon dioxide for the dinoflagellates. Taking our light bulbs: if we were to power them with renewable energy sources, we would significantly reduce carbon dioxide emissions. In the long term, such a switch is clearly beneficial to humans and the rest of the Earth System, and it might be one small step on the journey to a Kardashev Type 1 civilization. Such a switch requires clear forward planning and international agreements, like that of the Paris accord. It is an approach that develops positive – not negative – feedback mechanisms. Thus, transitioning away from the use of hydrocarbons would help enable cities to continue to grow, for economies to flourish, and for more people to be taken out of poverty. It would certainly help to prevent the potential widespread climate and oceanographic impact of using non-renewable hydrocarbons far into the future.

The incandescence of Earth’s estimated 12 billion light bulbs is just one component of the huge energy consumption of urban areas in the early 21st century. Keeping these light bulbs glowing sustainably, using renewable sources, is part of the task of keeping the lights on for all of humanity.

Next time, in the final chapter of this series, Killian Quigley looks deeper into the ways we think about the relationship between “nature” and cities. He discusses a diverse group of writers who emphasise the importance of subjective, sensory experience of urban space. And he contributes to calls for fiction-makers – writers, filmmakers, theatre-practitioners, and artists of all kinds – to keep imagining mutualistic future cities, and for all of us to read and act upon their visions.


1. Hoornweg, D., and Pope, K. (2014). Socioeconomic pathways and regional distribution of the world’s 101 largest cities. Global Cities Institute, Working Paper
2. Organisation for Economic Co-operation and Development. (2016). OECD Regional Outlook 2016: Productive Regions for Inclusive Societies. Paris: OECD Publishing. Access here

3. Neumann, B., Vafeidis, A. T., Zimmermann, J., and Nicholls, R. J. (2015). Future Coastal Population Growth and Exposure to Sea-Level Rise and Coastal Flooding – A Global Assessment. PLOS One, 10(3). 
4. Price Waterhouse Coopers. (2017). The world in 2050 – summary report. Access here

Mark Williams is a Professor of Palaeobiology at the University of Leicester, UK. He is interested in the evolution of the biosphere over geological timescales, with an emphasis on understanding the rate and degree of current biological change. He is a founding member of The Anthropocene Working Group, and with Jan Zalasiewicz, is the author of the popular science books ‘The Goldilocks Planet’ (2012), ‘Ocean Worlds’ (2014) and ‘Skeletons: the frame of life’ (2018, Oxford University Press).

Jan Zalasiewicz is a Professor of Palaeobiology at the University of Leicester, UK. In early career he was a field geologist and palaeontologist at the British Geological Survey. Now, he teaches geology and Earth history to undergraduate and postgraduate students, and studies fossil ecosystems and environments across over half a billion years of geological time. Over the last few years he has helped develop ideas on the Anthropocene, the concept that humans now drive much geology on the surface of Earth, and chairs the Anthropocene Working Group of the International Commission on Stratigraphy. His writing includes the books The Earth After Us (2008), The Planet in a Pebble (2010) and Rocks: A Very Short Introduction (2016).