Speculative biology
Abstract
Apocalypse, similar to its Biblical term is defined as a global event, causing mass extinction of life and humankind. The causes for this range from drastic changes in climate to nuclear war or asteroid collision. As result most of the Earth’s surface becomes uninhabitable. Assuming that at least part of the human race would find a way to survive the apocalypse, it will be isolated in some kind of refuge, limited in both space and natural resources, and characterized by living conditions, quite different from the contemporary Earth. Obviously, ensuring food supplies for the population would be a major challenge along with ensuring proper health status and sufficient energy. The current paper deals with the challenges in front of agriculture in such a post-apocalyptic world.
Classification of apocalypses
First of all, we must make clear that apocalypse is an inaccurate term, based on religious beliefs and is not formally used to describe the events of mass extinction. The official term, used in Cameron’s classification scheme is Catastrophic Event of Global Scale, Incompatible with Life. Such events may be caused by numerous factors, which are divided into biotic (caused by a living organism), abiotic (caused by non-living environmental factors), and anthropogenic (results of human activity). Furthermore, each of these can be classified as earthbound and extra-terrestrial.
The biotic factors are comparatively few and include infectious agents, such as (and mostly) viruses, although this could be contradictory. First, an infectious agent usually affects a single species or a limited number of species and could be hardly classified as a catastrophic event. Also, it is widely assumed that a virus of a scale to cause mass extinction would be intentionally or unintentionally modified in a lab [1] and thus, classified as an anthropogenic factor. Therefore, the only purely biotic cause for mass extinction would be the invasion of alien species from outer space.
Abiotic factors are numerous and often interconnected. For example, a volcano eruption would lead to tonnes of dust, which will prevent the sunlight from reaching the Earth’s surface and will cause an extreme drop in temperature to low grades, incompatible with life [2]. Similarly, an increase in the mean temperature will cause melting of the ice caps and flooding of the land surface [3].
Finally, the anthropogenic factors are considered the most probable and include mainly nuclear war [4] and the creation of autonomic artificial intelligence, turned against humanity (also called machine terror) [5]. Clearly, some of the abiotic factors may be also mixed with anthropogenic influence.
The next classification scheme considers whether the catastrophic event is limited to the land surface or will also affect life in the world ocean and whether the impact will be temporal – allowing re-population of the planet after a certain amount of time, or terminal – leading to constant incompatibility with life (including the disintegration of the planet).
Finally, the catastrophic event may be categorized according to the level of impact on life. In terms of affected species (not including prokaryotes), the catastrophic events are classified as low (20-40% extinct species), medium (41-60% extinct species), high (61-80% extinct species, very high (81-95%) and terminal (>96%). It was roughly estimated that life on Earth would not be able to restore to be habitable for humans if more than 95% of the existing species go extinct. Of course, the extinction of even less than 20% of the species would have a dramatic effect, but it is believed this could be compensated either through natural processes or with human intervention.
The concept of refuges
As a catastrophic event on a global scale is supposed to cause a significant reduction in the human population, many defense programs were directed to planning a liveable closed environment where at least some part of humanity, along with other plant and animal species will be able to escape and survive the apocalypse – the so-called refuge. It is hard to estimate how many exactly, but such refuges may sustain the life of between several tens of thousands to several million people. This is all in the worst case when humanity did not successfully colonize other planets.
The proposed refuges design varies significantly according to the cause and consequences of the catastrophic event, but it could be briefly summarized as 1) floating [3], flying , or constantly moving cities [7] or compartments [8]; 2) underground cities or bunkers [9]; 3) orbital or wandering space stations [10] or spaceships.
All kinds of refuges must provide: 1) defense against the main cause of the catastrophic event along with other possible secondary negative impacts; 2) appropriate atmosphere to sustain breathing; 3) sufficient energy to sustain all needs; 4) sufficient drinkable water and 5) sufficient food production. Unfortunately, the capacity of the refuge to ensure the above determines the number of people, and wealthier citizens are more probable to receive a place in the refuge than ordinary people.
As the refuge is commonly designed as a self-sufficient, closed system, the production of food (or food security) is among the most challenging tasks. Bellow some of the main strategies are discussed, but most importantly, none of the refuges could be a fully closed system, because there will be a need for a constant supply of inorganic (and organic, if possible) compounds, either from the surrounding environment or with probes, sent to Earth or another planet.
External food supplies
In the most advantageous scenario, when the land surface is not completely uninhabitable or the world ocean is not significantly affected, food security could be ensured by external food supplies. These may include harvesting marine life or food from other wild sources as well as the creation of static farms outside the shelter. Obviously, on a flooded Earth the rich and productive marine ecosystem may offer enough resources to floating cities and if the atmosphere and sun radiation are not completely disadvantageous to life, food could be grown in high-tech farms.
Food synthesis
Generally, food synthesizers look fancy. You put something (or nothing) and at the end, you have a nice-looking meal. In the limited space of a refuge, they would be a perfect choice, because they are small and produce food fast. Unfortunately, the situation is slightly different. Let us start with the fact that the minimum healthy food supply should consist of proteins (or at least amino acids), carbohydrates, lipids, a range of vitamins, and inorganic elements, even in trace amounts. A synthesizer, making all of these from inorganic compounds will be an extremely sophisticated and energy-demanding machine, although not impossible.
Much more suitable are the food processors – machines, constructed to turn organic matter into human food. This organic matter could be either non-edible (even fossil fuels), organic waste, or, in the optimal case, purposely-cultivated autotrophic bacteria. In the latter case, as bacteria do synthesize everything from inorganic matter, the task of the food processor would be to simply clear the potentially toxic substances and to transform the organic matter into the most appropriate for human consumption.
In vitro food
In vitro growth of a variety of plants and animal cells, tissues and organs is possible for decades. This means that under controlled conditions and in a relatively simple nutritional solution (e.g. growth medium) organismal cells are able to expand and propagate. Thus, relatively simply and in limited space you can produce a suspension of tomato fruit cells or bovine muscle fibers. The obvious advantage is that the shape and flavor of the produced food will be more pleasant and acceptable than the pastes and juices, produced by food processors and synthesizers. The growth medium could be easily produced by machines, similar to food processors.
However, there are several disadvantages, mainly related to the strict requirement for an absolutely sterile environment in which the cultures are grown. Bacterial or fungal contamination would lead to the devastating loss of the cultures. We should also consider the somaclonal variation – the accumulation of mutations in DNA, which will gradually lead to non-viable or irreversibly altered cell lines.
“Classic” farming
We have seen this, as nice shelves with strawberries, compartments with farmed pigs, and even a whole marine ecosystem for oyster and sushi-fish harvesting. Apparently, this is the most attractive choice in terms of the end product, but also the most demanding in terms of resources and space. Especially the breeding of live animals will require an enormous amount of plant food. The constant interbreeding between closely related individuals will eventually lead to a decline in viability. Moreover, the enclosed breeding in a limited space of multiple animals of the same species will greatly increase their susceptibility to infectious diseases and an outbreak of such will be devastating. Therefore, a refuge will be able to provide proper meat, but it would be far more appropriate for a vegan society.
In terms of energy supply, the most important consumer will be the artificial illumination, provided to substitute for the solar radiation and crucially important for plant photosynthesis. Apparently, a preference will be given to fast-growing, nutritious, and resource unpretentious plants and varieties.
A closed ecosystem
The utopia of a closed ecosystem [claustrosphere, 11] is certainly possible. This might be also the best option for an orbital refuge. If enough energy from solar radiation is provided, a fully closed environment with sufficient biodiversity of bacteria, algae, fungi, plants, and animals will be able to properly perform the nitrogen and carbon cycles and all nutrients and inorganic elements will be recycled. There are, however, several important considerations to be taken into account.
First of all, the included and excluded species should be finely calculated in order to establish a proper balance. The presence of highly invasive species and pathogens must be minimized. It is also important to assume, that humans must be the apex (and possibly the only) predator in the claustrosphere and their number must be constant within certain limits. Otherwise, with no option for dispersion into new territories, the balance could be easily destroyed from the top. Finally, in such a close ecosystem the traditional crop plants and farm animals will not be overall beneficial to the ecosystem as they tend to be extremely resource-consuming and destructive.
It may be possible, however, to construct an agrosphere, if the said consist of several (at least four) isolated compartments. As such, each compartment will be used for different purposes for a certain time period. This is similar to crop rotation. In a simplified example, one compartment will be first used for the cultivation of legumes, then for the cultivation of cereals, followed by recovery, and finally for cattle breeding. Unlike the claustrosphere, the agrosphere could not be self-sustained and will need constant monitoring and maintenance.
[1] Stephen King (1978) The Stand. Doubleday
[2] Mike Mullin (2011) Ashfall. Tanglewood Press
[3] Kevin Reynolds (1995) Waterworld. Universal Pictures
[4] William Brinkley (1988) The Last Ship. Viking Press
[5] James Cameron (1984-2019) Terminator franchise. StudioCanal
[6] John Brosnan (1988-1991) The Sky Lords. Victor Gollancz Ltd
[7] Phillip Reeve (2001-2006) Mortal Engines. James Cameron
[8] Jacques Lob, Benjamin Legrand, Olivier Bouquet, Alexis Nolent (1984-2020) Le Transperceneige. Casterman
[9] Ryan Murphy, Brad Falchuk (2018) American Horror Story: Apocalypse. FX Networks
[10] Jason Rothenberg (2014-2020) The 100. CBS
[11] Ben Elton, 1993, This Other Eden, Sphere Books.