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openspace4lifeThis next one is much longer and was my final paper for Intro Environmental Studies. It was titled "Can humanity become independent of the natural environment?"
Introduction
During the past few centuries, the scale of human activity has become more and more global. Only in the past few decades, however, has the environmental movement become influential enough to force important decision-makers to consider seriously the consequences of this increasing scale for the environment. In the intervening time, humanity has set numerous complex processes in motion that interact in often unpredictable ways with the even more complex natural world. In the words of J. R. McNeill, we have “undertaken a gigantic uncontrolled experiment on the earth” (4).
Of course, Earth and its biosphere have weathered many great disasters throughout their history, but many of the human-induced changes are different in kind from any of these. Human activity has resulted in low levels of thousands of new chemicals in the air, water, and earth, many of them purposely designed for lethality. We have destroyed natural habitats of all kinds in almost every part of the world and replaced them with vast expanses of low-diversity crop fields and urban environments. We have extracted massive quantities of materials that had remained deep underground for millions of years—and we have done all this in an eyeblink of geological and evolutionary time. We have even short-circuited evolution itself through rapid selective breeding programs and, more recently, genetic engineering.
We have no way of knowing if or when any of these changes might backfire on us catastrophically. Some possibilities are somewhat predictable, such as the potential shutdown of most ocean currents due to an influx of fresh water from melting glaciers (Joyce and Keigwin). But others, including ecological regime shifts like the recent sudden collapse of the Aleutian ecosystem (Springer et al.), result from chain reactions involving so many factors that we’re very unlikely to see the consequences of our actions clearly enough to take appropriate preventive measures far enough in advance.
Almost all of the methods for defending humanity against these potential crises involve cutting back or halting one or more of our interactions with the biosphere. We can reduce our impact by appropriating fewer natural resources and emitting less waste, and we can take measures to mitigate the consequent impact of the environment on humanity, such as the health effects of pollutants and the loss of ecosystem services due to depletion of natural resources. This paper discusses how feasible it would be to cut off nearly all of these interactions, isolating humanity from nature. In other words, can we shut down all of our resource-extraction operations and learn to depend almost entirely on artificial, closed-loop production systems whose wastes are recycled rather than being released into the natural biosphere?
I will discuss four categories of interactions that we would have to terminate, corresponding to the traditional four elements of the environment: air, water, land, and living things.
Air
A continuous supply of breathable air is the most basic necessity for human life, and providing that supply through artificial means would pose a daunting challenge. First, we would have to create an enclosed environment separate from the global atmosphere, in which people could live their entire lives without going outside (though they hopefully wouldn’t have to). One obvious method would be to make all buildings and vehicles airtight and replace all doors to the outside with airlocks. This, combined with some system to convert the carbon dioxide we exhale back into oxygen, may be the cheapest possible solution, though “cheap” here is clearly a very relative term.
Another possibility along these lines is Paolo Soleri’s arcology concept. Soleri envisioned a city contained in a single building a few hundred stories tall, covering a ground area of only three or four square miles (Soleri 49) and thus reducing or eliminating the need for motorized transport within the city. The cost of building an arcology is difficult to calculate, but it would certainly cost many times more than a typical skyscraper, probably in the ten- to hundred-billion-dollar range.
We could also try to move everyone underground. The main advantage to this option is that it would be comparatively easy to make a system of subterranean chambers and tunnels airtight. But even with central lighting systems (Coates 6) to cut down on electricity costs, the sheer amount of tunneling required would probably make this one of the most expensive options. According to a report from the Norwegian University of Science and Technology, typical drilling and/or blasting costs per meter for a three-kilometer tunnel range from about 500 to 2000 kroners ($800-$3200) depending on tunnel width (Tunnelling 11), and this cost can double or triple when the cost of concrete is included (Tunnelling 21). There are over a million kilometers of urban roads in the United States, and over six million total kilometers of roads (Public Road Length). Even assuming efficiency measures reducing the total required tunnel length (including living space, offices, factories, etc.) to only a hundred thousand kilometers, and using minimum cost figures (tunnel cross-sections of 10 m2 or less), it would cost over a hundred billion dollars nationally just to create the tunnels. And in any case, the psychological effects of living underground would probably be quite severe.
If the outside environment does become uninhabitable, whether due to deadly pollution levels or global climate change, human sanity will probably still require at least an occasional visit to some kind of “open space.” The most obvious solution, enclosing large areas with glass domes, while probably potentially feasible (Coates 5), would be enormously expensive. Consider the $150-million construction cost of the 1.27-hectare airtight greenhouse structure for Biosphere 2 (Bunk), which held only eight people. Also, during the first two-year closure, Eugene P. Odum calculates the energy and natural-gas costs at $150,000 per person per month. A large fraction of the electricity went to power “the complex pumping and filtering machinery . . . that circulated the air [and] maintained its pressure,” and “[m]uch of the natural gas was expended in heating and cooling the living space” (Odum 18). Furthermore, Biosphere 2’s N2O concentrations increased at a rate of 40 ppm per year because the glass enclosure “eliminated more than 99% of [the] incident UV” that ordinarily breaks up N2O in Earth’s stratosphere (Allan and Nelson). One variant on the dome concept is a giant plastic tent, which might be cheaper to build and could be made to absorb less UV radiation, but would probably be even harder to keep at a reasonable temperature, especially if outside climate conditions were extreme.
No matter which of these methods we chose, costs would go up as we increased the size of our enclosed structures, so living conditions would probably be very crowded. The social implications of this situation would be enormous. The specifics of these issues and how they might be dealt with are questions beyond the scope of this paper. Many science-fiction stories have been written on the topic; Isaac Asimov’s novel The Caves of Steel is one excellent example.
As for a method of renewing the oxygen supply, the obvious answer is to grow plants inside the sealed environment. But it will take careful engineering to get this to work. In Biosphere 2, oxygen levels fell “from the initial levels of 20.9 to . . . 14.2% in mid January 1996, 16 months after closure” despite the abundance of plant life inside; much of the CO2 was “taken up by interior structural concrete which had been left unsealed” before the plants could convert it back to oxygen (Allan and Nelson).
Water
Assuming we have self-contained structures with good air supplies, what do we do for water? Humans need water to survive as much as they need air. We must either get it from the environment or recycle that which is already in our water systems. At present we have no water treatment methods capable of converting sewage and industrial wastewater into drinkable water, but treated wastewater is used for other purposes, such as "landscape irrigation of highway medians, golf courses, parks, and schoolyards . . . industrial uses such as power station cooling towers, oil refinery boiler feed water, carpet dyeing, recycled newspaper processing, and laundries . . . [and] agricultural uses such as irrigation of produce, pastures for animal feed, and nursery plant products" (Water Recycling xi). Also, this wastewater is commonly injected into the water table near aquifers used for drinking water, on the theory that filtering through the earth can accomplish what our treatment plants cannot.
But in Biosphere 2, the output of the wetland-based wastewater recycling system reached “the high purity levels required in drinking water” (Space Biospheres Ventures). If they could do it, why can’t we?
The mixing of all of our household and industrial wastes in sewers creates an obstacle to recycling our drinking water within a closed, human-built system by making it nearly impossible to separate out all of the dangerous compounds. For example, sludge, the solid portion of the waste that comes out of treatment plants and is often used as a fertilizer, has been found to contain chemicals such as flame retardant (Crapshoot). Technologies such as the Koch/Infinity hydrocarbon/oil removal filters, which the company claims “can completely remove all types of organic compounds” from a waste stream (Koch), may be part of the solution, but we may need to rethink our entire waste-processing system if we are to make it into a closed loop. We will need to remove many waste products from the system much earlier in the process, whether through filters, separate pipe systems, or simply storing them at the site where they were produced. Then we will need to find ways to transform these wastes back into usable forms.
Land
Unless all of humanity migrates to underground cities, or to space colonies (an option so unfeasible at present that it isn’t really worth discussing), humans will have to take up some of Earth’s surface area for a long time to come. If we stop the increase in the land area we use for living space by building up rather than out, then hopefully we will eventually reverse the process of sprawl (the main goal of Soleri’s arcology). For these measures to be effective over the long term, of course, we need to stabilize the human population size. But the human impact on land extends far beyond our living space.
For instance, we mine the earth for building materials for our dwellings and the products we fill them with. In the case of metals and minerals, there are only two ways to cut off our dependence on continued extraction of Earth’s supplies: recycle what has already been extracted, or get more from elsewhere (e.g. asteroids). Even if the latter solution turns out to be feasible, it merely puts off dealing with the problem of limited resources.
Some corporations have already committed to “extended product responsibility,” that is, taking back products at the end of their lives and reusing or recycling them. However, a closed-loop system has more stringent requirements: since the total amount of material is constant, recycling must be 100% efficient just to keep the number of products constant. (Again, the number of users of the products must also remain roughly constant.) Efficiency measures to make each product with fewer resources will only get us so far—although, since recycling takes a lot of energy, such efficiency measures can make the system much less costly. Simple products such as paper, metal cans, and glass bottles are already basically 100% recyclable. A few companies making more complex products are progressing toward complete recyclability, sometimes encouraged by new regulations. For instance, car companies doing business in the European Union have to make sure that “no later than 1 January 2015 . . . the reuse and recovery [of materials] shall be increased to a minimum of 95 %” of each car’s mass (Directive 2000/53/EC 35).
Luckily, in the case of plastics we have another option: using plant products instead of petroleum to produce so-called “bioplastics,” already being phased in by some Japanese companies (Bioplastic). Essentially, this turns plastic into a renewable resource.
Unfortunately, replacing petroleum and other fossil fuels in their role as energy sources is much more problematic. Of course, all known ways to supply energy for human use require environmental inputs of some kind. However, given that the goals of separating ourselves from nature are mainly to avoid causing or suffering from the effects of severe environmental change, we can see that some energy sources are more consistent with these goals than others. Fossil fuels are highly polluting and most climate scientists consider them the major cause of global warming. Furthermore, fossil fuels will eventually require more energy to extract than they are worth, and if our civilization is still highly dependent on them at that point, the result will be disastrous. Nuclear energy also has potentially environmentally damaging byproducts and limited supplies, about twice as much total energy reserve as coal if used in fast-breeder reactors (Golob and Brus 5, 8).
Solar, wind, geothermal, biomass, and hydroelectric power, by contrast, have fairly low environmental impact (loss of wildlife habitat under dam reservoirs is probably the biggest concern), and can be expected to keep producing indefinitely under almost any likely environmental conditions. There are some grounds for optimism about the prospect of completely replacing fossil fuels with renewable energy sources in the not-too-distant future. In 1990, the Department of Energy projected that with some technology improvements and/or political incentives, wind power in the U.S. could provide “nearly 11 quads [370 gigawatts] by the year 2030” (Golob and Brus 153). If the United States’s surplus farmlands “were converted to biomass energy plantations . . . [they] could produce up to 20 quads [670 gigawatts] of ethanol fuels per year” (Golob and Brus 60), although achieving similar results inside airtight structures would be difficult. The projected electricity demand in the United States during the year 2010 is 900 gigawatts (Patel 1), less than the sum of the two numbers above; however, this number will grow further by 2030, and it doesn’t take into account non-electrical energy demand. The National Renewable Energy Laboratory gives a maximum annual production rate of 500 gigawatts worth of photovoltaic production capacity in 50 years (PV FAQs). Producing solar panels at this rate for a few years would meet all U.S. electricity demand. However, the necessary technology may take much longer to develop than this optimistic estimate suggests. One more helpful fact is that global hydropower production has the potential to increase roughly sevenfold, to “about 15.1 trillion kilowatt-hours of electricity per year” (Golob and Brus 36).
Living things
Agriculture, the most obvious and necessary human use of living things, represents one of the most pressing reasons why we must eliminate our dependence on fossil fuels before they run out. Otherwise, farm equipment and fertilizer production will grind to a halt, precipitating a global food crisis. Agriculture is also a critically important land-use issue in its own right; it takes up far more land area than any other human activity—an area about the size of South America as of 1995 (McNeill 212).
Farms are an excellent example of a fuzzy boundary between man and nature. For the purposes of this paper, however, I will consider crops and livestock as an extension of human systems, extracting the resources they need to grow from the natural world around them, often in a mutually beneficial manner. For example, few crop plants can survive without the networks of symbiotic mycorrhizal fungi in the soil that extend the reach of their roots (Wolfe 94), unless they are grown hydroponically. Soil-based indoor agriculture thus requires bringing the mycorrhizae inside along with the soil.
So in a human system closed off from nature, which is the better option for agriculture, soil or hydroponics? In the case of Biosphere 2, “Mission Two accomplished food sufficiency during their 6-month closure” using conventional farming, but the diet “was nutritionally dense and calorically restricted” (Allen and Nelson). It’s widely acknowledged that hydroponics costs more per unit area than conventional agriculture, but it can also produce much higher yields per unit area, and has several other advantages as well, such as more efficient water use (Resh 27-29). And much of the cost increase for indoor hydroponics is due to greenhouse construction, so if we’re already committed to building large enclosures with proper lighting for the growth of oxygen-producing plants, hydroponics starts to look very attractive indeed.
What about animals? A report from a NASA workshop points out that “meat production in a CELSS [Controlled Ecological Life Support System] would be quite inefficient, requiring large areas and volumes to produce fodder” for the livestock to eat (Salisbury and Clark 34). Indeed, because of the space constraints discussed earlier, economics alone would probably drive a shift toward vegetarianism. (Similarly, farming of trees and their fruits would likely decline due to the large amounts of space and nutrients trees require. Widespread use of 100%-post-consumer paper products would become a priority, as well as recycling of lumber from old buildings.)
Another, more radical option for replacing conventional agriculture is synthetic food. A common assumption is that “[h]uman existence requires . . . at least 42 nutrients [including] water, energy sources, vitamins, minerals, trace elements, essential amino acids, and essential fatty acids” (Welch 1), where “energy sources” can be taken to mean carbohydrates that the body reduces to glucose and uses to drive cellular respiration. Complex carbohydrates are already being synthesized for medical purposes (Borman), and synthetic vitamins and minerals have been on the market for some time, though there is extensive debate as to whether natural vitamin supplements are superior because they include ingredients that synthetic vitamins don’t (Obikoya). Synthetic fatty acids, trans-fatty acids in particular, have also resulted in controversy. But at this point, it seems fairly likely that all of the 42 essential nutrients can be synthesized. The question is whether it would be remotely economical to feed the world this way, and at present, the answer is almost certainly no. Again, hydroponics is probably the way to go.
Humans depend on far more species than those we use for food. At the most basic level, we need plants and algae to make the oxygen we breathe. Plants also supply us with fiber products without which most types of cloth could not exist. New medically useful substances are often discovered in nature, particularly in regions of high biodiversity such as tropical rainforests.
Finally, modern agriculture would be in trouble without the ability to crossbreed crop species with wild “[r]elatives of commercial species . . . to improve crop yield, nutritional quality, durability, responsiveness to different soils and climates, and resistance to pests and diseases” (Plotkin 110). Some of these goals can be achieved through artificial selection, but when we need to add a completely new trait, the only alternative to crossbreeding is genetic engineering, a dangerous technology based on faulty assumptions (Commoner) which in any case also requires another organism to have the genes we want.
Luckily, if we succeed in creating a closed human environment that neither extracts resources from nor emits pollutants into the natural world, we can predict that the rate of loss of biodiversity will slow drastically. And since the process of searching for wild species with valuable traits and bringing in a few individuals to breed in the lab doesn’t represent a major extraction of resources, we can consider it safe to go on exploiting Earth’s biodiversity in this fashion.
Is separation really desirable?
The principle argument against separating humanity from nature is that if we no longer depend on Earth’s resources for our survival, we will feel free to release as much pollution as we want into the environment outside of our closed habitats. In essence, we won’t be affected by the consequences of our pollution, so we will have no motivation to stop polluting.
However, it’s worth noting that most of today’s major pollutants result from the use of fossil fuels and petroleum products; if we stopped extracting fossil fuels, these pollution sources would cease. Moreover, some forms of pollution would become uneconomical in a closed system. For instance, fertilizer and pesticide runoff from indoor agriculture would have to be piped outside instead of simply flowing into the nearest stream. Also, minimizing global climate instability would still be important because it would lower the cost of temperature control in large enclosed spaces.
Furthermore, even people who live with massive amounts of pollution often don’t see any good reason to fight against it, because they see the pollution as a price they’re willing to pay for prosperity. Chinese cities such as Beijing exemplify this tradeoff (Hertsgaard 166). The real problem of pollution is that we may not be able to muster the will to change the systems that produce it before its effects become catastrophic. In case such a catastrophe becomes impossible to avert, it may be worthwhile to mitigate the potential impact on humanity by putting walls between us and the environment.
Another major argument against such walls is the philosophical idea that because humans are part of nature, we simply can’t separate ourselves from it. But our continued pollution and resource extraction is destroying more and more of the natural world; if we can halt these activities, we make it more likely that people will continue to be able to go into the wilderness and commune with nature.
One especially telling argument is that because of the high cost of the enclosures I’ve proposed, only the wealthiest segments of the population will be able to afford to live in them. One answer to this is that the more the technologies needed to create the enclosures are used, the cheaper they will get, and at least some of them will become available to wider populations. Also, the only organizations likely to take on such a large project with such long-term goals are national governments, so in the catastrophe scenario, political pressures would hopefully result in the accommodation of poorer people within the enclosures. In other scenarios, given a stable population, poor people living outside the enclosures would no longer have to expand into wildlife habitat at anywhere near the current rate. And since resource use and pollution per capita is generally proportional to wealth, moving the upper and middle classes into self-sufficient enclosures should eliminate the bulk of the environment-damaging processes. None of these are complete answers to this objection. However, the balance of the arguments suggests that separation is a favorable solution.
Conclusions
Overall, the project to make humanity independent from nature, with the exceptions of energy sources and some land area, appears just barely technically and economically feasible. Creating an air system separate from the global atmosphere is by far the most difficult aspect of the project, which suggests the need for a partial solution: We could continue to depend on the atmosphere while taking every possible measure to avoid disastrous atmospheric changes, including a rapid shift toward renewable energy sources to reduce the impact of global warming. While no longer integrated into the airtight-structure plan, hydroponics would still be a valuable part of the solution because it eliminates agriculture’s impact on the soil, reduces the total land area needed for farming, and can also be implemented in barren regions where the local environmental impact is lower (and where local populations would otherwise depend on imports for food). Total recycling of water and as many building materials and artificial chemicals as possible rounds out the proposal.
Politically and socially speaking, feasibility considerations are much more complex. The governments that would initiate this project, and the corporations they would hire to carry it out, are huge organizations with considerable inertia. Each is deeply invested in a certain way of doing things and has a strong incentive to resist sweeping changes. However, as scientists and the environmental movement continue to work to raise public awareness about the potential for ecological disasters, popular pressure may overcome inertia and force our leaders to move faster toward a safer world.
Works cited
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Coates, Joseph F. “Wild ideas in future cities.” The Bridge vol. 29, no. 4 (Winter 1999): 4-9. Online. National Academy of Engineering. 18 November 2004. Available http://www.nae.edu/nae/bridgecom.nsf/weblinks/NAEW-63BQLF/$FILE/brwinter99.pdf?OpenElement.
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Hertsgaard, Mark. Earth Odyssey: Around the world in search of our environmental future. New York, NY: Broadway Books, 1998.
Joyce, Terrence, and Lloyd Keigwin. “Abrupt Climate Change: Are We On the Brink of a New Little Ice Age?” Ocean and Climate Change Institute. Online. Woods Hole Oceanographic Institution. 19 November 2004. Available http://www.whoi.edu/institutes/occi/currenttopics/abruptclimate_joyce_keigwin.html.
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During the past few centuries, the scale of human activity has become more and more global. Only in the past few decades, however, has the environmental movement become influential enough to force important decision-makers to consider seriously the consequences of this increasing scale for the environment. In the intervening time, humanity has set numerous complex processes in motion that interact in often unpredictable ways with the even more complex natural world. In the words of J. R. McNeill, we have “undertaken a gigantic uncontrolled experiment on the earth” (4).
Of course, Earth and its biosphere have weathered many great disasters throughout their history, but many of the human-induced changes are different in kind from any of these. Human activity has resulted in low levels of thousands of new chemicals in the air, water, and earth, many of them purposely designed for lethality. We have destroyed natural habitats of all kinds in almost every part of the world and replaced them with vast expanses of low-diversity crop fields and urban environments. We have extracted massive quantities of materials that had remained deep underground for millions of years—and we have done all this in an eyeblink of geological and evolutionary time. We have even short-circuited evolution itself through rapid selective breeding programs and, more recently, genetic engineering.
We have no way of knowing if or when any of these changes might backfire on us catastrophically. Some possibilities are somewhat predictable, such as the potential shutdown of most ocean currents due to an influx of fresh water from melting glaciers (Joyce and Keigwin). But others, including ecological regime shifts like the recent sudden collapse of the Aleutian ecosystem (Springer et al.), result from chain reactions involving so many factors that we’re very unlikely to see the consequences of our actions clearly enough to take appropriate preventive measures far enough in advance.
Almost all of the methods for defending humanity against these potential crises involve cutting back or halting one or more of our interactions with the biosphere. We can reduce our impact by appropriating fewer natural resources and emitting less waste, and we can take measures to mitigate the consequent impact of the environment on humanity, such as the health effects of pollutants and the loss of ecosystem services due to depletion of natural resources. This paper discusses how feasible it would be to cut off nearly all of these interactions, isolating humanity from nature. In other words, can we shut down all of our resource-extraction operations and learn to depend almost entirely on artificial, closed-loop production systems whose wastes are recycled rather than being released into the natural biosphere?
I will discuss four categories of interactions that we would have to terminate, corresponding to the traditional four elements of the environment: air, water, land, and living things.
Air
A continuous supply of breathable air is the most basic necessity for human life, and providing that supply through artificial means would pose a daunting challenge. First, we would have to create an enclosed environment separate from the global atmosphere, in which people could live their entire lives without going outside (though they hopefully wouldn’t have to). One obvious method would be to make all buildings and vehicles airtight and replace all doors to the outside with airlocks. This, combined with some system to convert the carbon dioxide we exhale back into oxygen, may be the cheapest possible solution, though “cheap” here is clearly a very relative term.
Another possibility along these lines is Paolo Soleri’s arcology concept. Soleri envisioned a city contained in a single building a few hundred stories tall, covering a ground area of only three or four square miles (Soleri 49) and thus reducing or eliminating the need for motorized transport within the city. The cost of building an arcology is difficult to calculate, but it would certainly cost many times more than a typical skyscraper, probably in the ten- to hundred-billion-dollar range.
We could also try to move everyone underground. The main advantage to this option is that it would be comparatively easy to make a system of subterranean chambers and tunnels airtight. But even with central lighting systems (Coates 6) to cut down on electricity costs, the sheer amount of tunneling required would probably make this one of the most expensive options. According to a report from the Norwegian University of Science and Technology, typical drilling and/or blasting costs per meter for a three-kilometer tunnel range from about 500 to 2000 kroners ($800-$3200) depending on tunnel width (Tunnelling 11), and this cost can double or triple when the cost of concrete is included (Tunnelling 21). There are over a million kilometers of urban roads in the United States, and over six million total kilometers of roads (Public Road Length). Even assuming efficiency measures reducing the total required tunnel length (including living space, offices, factories, etc.) to only a hundred thousand kilometers, and using minimum cost figures (tunnel cross-sections of 10 m2 or less), it would cost over a hundred billion dollars nationally just to create the tunnels. And in any case, the psychological effects of living underground would probably be quite severe.
If the outside environment does become uninhabitable, whether due to deadly pollution levels or global climate change, human sanity will probably still require at least an occasional visit to some kind of “open space.” The most obvious solution, enclosing large areas with glass domes, while probably potentially feasible (Coates 5), would be enormously expensive. Consider the $150-million construction cost of the 1.27-hectare airtight greenhouse structure for Biosphere 2 (Bunk), which held only eight people. Also, during the first two-year closure, Eugene P. Odum calculates the energy and natural-gas costs at $150,000 per person per month. A large fraction of the electricity went to power “the complex pumping and filtering machinery . . . that circulated the air [and] maintained its pressure,” and “[m]uch of the natural gas was expended in heating and cooling the living space” (Odum 18). Furthermore, Biosphere 2’s N2O concentrations increased at a rate of 40 ppm per year because the glass enclosure “eliminated more than 99% of [the] incident UV” that ordinarily breaks up N2O in Earth’s stratosphere (Allan and Nelson). One variant on the dome concept is a giant plastic tent, which might be cheaper to build and could be made to absorb less UV radiation, but would probably be even harder to keep at a reasonable temperature, especially if outside climate conditions were extreme.
No matter which of these methods we chose, costs would go up as we increased the size of our enclosed structures, so living conditions would probably be very crowded. The social implications of this situation would be enormous. The specifics of these issues and how they might be dealt with are questions beyond the scope of this paper. Many science-fiction stories have been written on the topic; Isaac Asimov’s novel The Caves of Steel is one excellent example.
As for a method of renewing the oxygen supply, the obvious answer is to grow plants inside the sealed environment. But it will take careful engineering to get this to work. In Biosphere 2, oxygen levels fell “from the initial levels of 20.9 to . . . 14.2% in mid January 1996, 16 months after closure” despite the abundance of plant life inside; much of the CO2 was “taken up by interior structural concrete which had been left unsealed” before the plants could convert it back to oxygen (Allan and Nelson).
Water
Assuming we have self-contained structures with good air supplies, what do we do for water? Humans need water to survive as much as they need air. We must either get it from the environment or recycle that which is already in our water systems. At present we have no water treatment methods capable of converting sewage and industrial wastewater into drinkable water, but treated wastewater is used for other purposes, such as "landscape irrigation of highway medians, golf courses, parks, and schoolyards . . . industrial uses such as power station cooling towers, oil refinery boiler feed water, carpet dyeing, recycled newspaper processing, and laundries . . . [and] agricultural uses such as irrigation of produce, pastures for animal feed, and nursery plant products" (Water Recycling xi). Also, this wastewater is commonly injected into the water table near aquifers used for drinking water, on the theory that filtering through the earth can accomplish what our treatment plants cannot.
But in Biosphere 2, the output of the wetland-based wastewater recycling system reached “the high purity levels required in drinking water” (Space Biospheres Ventures). If they could do it, why can’t we?
The mixing of all of our household and industrial wastes in sewers creates an obstacle to recycling our drinking water within a closed, human-built system by making it nearly impossible to separate out all of the dangerous compounds. For example, sludge, the solid portion of the waste that comes out of treatment plants and is often used as a fertilizer, has been found to contain chemicals such as flame retardant (Crapshoot). Technologies such as the Koch/Infinity hydrocarbon/oil removal filters, which the company claims “can completely remove all types of organic compounds” from a waste stream (Koch), may be part of the solution, but we may need to rethink our entire waste-processing system if we are to make it into a closed loop. We will need to remove many waste products from the system much earlier in the process, whether through filters, separate pipe systems, or simply storing them at the site where they were produced. Then we will need to find ways to transform these wastes back into usable forms.
Land
Unless all of humanity migrates to underground cities, or to space colonies (an option so unfeasible at present that it isn’t really worth discussing), humans will have to take up some of Earth’s surface area for a long time to come. If we stop the increase in the land area we use for living space by building up rather than out, then hopefully we will eventually reverse the process of sprawl (the main goal of Soleri’s arcology). For these measures to be effective over the long term, of course, we need to stabilize the human population size. But the human impact on land extends far beyond our living space.
For instance, we mine the earth for building materials for our dwellings and the products we fill them with. In the case of metals and minerals, there are only two ways to cut off our dependence on continued extraction of Earth’s supplies: recycle what has already been extracted, or get more from elsewhere (e.g. asteroids). Even if the latter solution turns out to be feasible, it merely puts off dealing with the problem of limited resources.
Some corporations have already committed to “extended product responsibility,” that is, taking back products at the end of their lives and reusing or recycling them. However, a closed-loop system has more stringent requirements: since the total amount of material is constant, recycling must be 100% efficient just to keep the number of products constant. (Again, the number of users of the products must also remain roughly constant.) Efficiency measures to make each product with fewer resources will only get us so far—although, since recycling takes a lot of energy, such efficiency measures can make the system much less costly. Simple products such as paper, metal cans, and glass bottles are already basically 100% recyclable. A few companies making more complex products are progressing toward complete recyclability, sometimes encouraged by new regulations. For instance, car companies doing business in the European Union have to make sure that “no later than 1 January 2015 . . . the reuse and recovery [of materials] shall be increased to a minimum of 95 %” of each car’s mass (Directive 2000/53/EC 35).
Luckily, in the case of plastics we have another option: using plant products instead of petroleum to produce so-called “bioplastics,” already being phased in by some Japanese companies (Bioplastic). Essentially, this turns plastic into a renewable resource.
Unfortunately, replacing petroleum and other fossil fuels in their role as energy sources is much more problematic. Of course, all known ways to supply energy for human use require environmental inputs of some kind. However, given that the goals of separating ourselves from nature are mainly to avoid causing or suffering from the effects of severe environmental change, we can see that some energy sources are more consistent with these goals than others. Fossil fuels are highly polluting and most climate scientists consider them the major cause of global warming. Furthermore, fossil fuels will eventually require more energy to extract than they are worth, and if our civilization is still highly dependent on them at that point, the result will be disastrous. Nuclear energy also has potentially environmentally damaging byproducts and limited supplies, about twice as much total energy reserve as coal if used in fast-breeder reactors (Golob and Brus 5, 8).
Solar, wind, geothermal, biomass, and hydroelectric power, by contrast, have fairly low environmental impact (loss of wildlife habitat under dam reservoirs is probably the biggest concern), and can be expected to keep producing indefinitely under almost any likely environmental conditions. There are some grounds for optimism about the prospect of completely replacing fossil fuels with renewable energy sources in the not-too-distant future. In 1990, the Department of Energy projected that with some technology improvements and/or political incentives, wind power in the U.S. could provide “nearly 11 quads [370 gigawatts] by the year 2030” (Golob and Brus 153). If the United States’s surplus farmlands “were converted to biomass energy plantations . . . [they] could produce up to 20 quads [670 gigawatts] of ethanol fuels per year” (Golob and Brus 60), although achieving similar results inside airtight structures would be difficult. The projected electricity demand in the United States during the year 2010 is 900 gigawatts (Patel 1), less than the sum of the two numbers above; however, this number will grow further by 2030, and it doesn’t take into account non-electrical energy demand. The National Renewable Energy Laboratory gives a maximum annual production rate of 500 gigawatts worth of photovoltaic production capacity in 50 years (PV FAQs). Producing solar panels at this rate for a few years would meet all U.S. electricity demand. However, the necessary technology may take much longer to develop than this optimistic estimate suggests. One more helpful fact is that global hydropower production has the potential to increase roughly sevenfold, to “about 15.1 trillion kilowatt-hours of electricity per year” (Golob and Brus 36).
Living things
Agriculture, the most obvious and necessary human use of living things, represents one of the most pressing reasons why we must eliminate our dependence on fossil fuels before they run out. Otherwise, farm equipment and fertilizer production will grind to a halt, precipitating a global food crisis. Agriculture is also a critically important land-use issue in its own right; it takes up far more land area than any other human activity—an area about the size of South America as of 1995 (McNeill 212).
Farms are an excellent example of a fuzzy boundary between man and nature. For the purposes of this paper, however, I will consider crops and livestock as an extension of human systems, extracting the resources they need to grow from the natural world around them, often in a mutually beneficial manner. For example, few crop plants can survive without the networks of symbiotic mycorrhizal fungi in the soil that extend the reach of their roots (Wolfe 94), unless they are grown hydroponically. Soil-based indoor agriculture thus requires bringing the mycorrhizae inside along with the soil.
So in a human system closed off from nature, which is the better option for agriculture, soil or hydroponics? In the case of Biosphere 2, “Mission Two accomplished food sufficiency during their 6-month closure” using conventional farming, but the diet “was nutritionally dense and calorically restricted” (Allen and Nelson). It’s widely acknowledged that hydroponics costs more per unit area than conventional agriculture, but it can also produce much higher yields per unit area, and has several other advantages as well, such as more efficient water use (Resh 27-29). And much of the cost increase for indoor hydroponics is due to greenhouse construction, so if we’re already committed to building large enclosures with proper lighting for the growth of oxygen-producing plants, hydroponics starts to look very attractive indeed.
What about animals? A report from a NASA workshop points out that “meat production in a CELSS [Controlled Ecological Life Support System] would be quite inefficient, requiring large areas and volumes to produce fodder” for the livestock to eat (Salisbury and Clark 34). Indeed, because of the space constraints discussed earlier, economics alone would probably drive a shift toward vegetarianism. (Similarly, farming of trees and their fruits would likely decline due to the large amounts of space and nutrients trees require. Widespread use of 100%-post-consumer paper products would become a priority, as well as recycling of lumber from old buildings.)
Another, more radical option for replacing conventional agriculture is synthetic food. A common assumption is that “[h]uman existence requires . . . at least 42 nutrients [including] water, energy sources, vitamins, minerals, trace elements, essential amino acids, and essential fatty acids” (Welch 1), where “energy sources” can be taken to mean carbohydrates that the body reduces to glucose and uses to drive cellular respiration. Complex carbohydrates are already being synthesized for medical purposes (Borman), and synthetic vitamins and minerals have been on the market for some time, though there is extensive debate as to whether natural vitamin supplements are superior because they include ingredients that synthetic vitamins don’t (Obikoya). Synthetic fatty acids, trans-fatty acids in particular, have also resulted in controversy. But at this point, it seems fairly likely that all of the 42 essential nutrients can be synthesized. The question is whether it would be remotely economical to feed the world this way, and at present, the answer is almost certainly no. Again, hydroponics is probably the way to go.
Humans depend on far more species than those we use for food. At the most basic level, we need plants and algae to make the oxygen we breathe. Plants also supply us with fiber products without which most types of cloth could not exist. New medically useful substances are often discovered in nature, particularly in regions of high biodiversity such as tropical rainforests.
Finally, modern agriculture would be in trouble without the ability to crossbreed crop species with wild “[r]elatives of commercial species . . . to improve crop yield, nutritional quality, durability, responsiveness to different soils and climates, and resistance to pests and diseases” (Plotkin 110). Some of these goals can be achieved through artificial selection, but when we need to add a completely new trait, the only alternative to crossbreeding is genetic engineering, a dangerous technology based on faulty assumptions (Commoner) which in any case also requires another organism to have the genes we want.
Luckily, if we succeed in creating a closed human environment that neither extracts resources from nor emits pollutants into the natural world, we can predict that the rate of loss of biodiversity will slow drastically. And since the process of searching for wild species with valuable traits and bringing in a few individuals to breed in the lab doesn’t represent a major extraction of resources, we can consider it safe to go on exploiting Earth’s biodiversity in this fashion.
Is separation really desirable?
The principle argument against separating humanity from nature is that if we no longer depend on Earth’s resources for our survival, we will feel free to release as much pollution as we want into the environment outside of our closed habitats. In essence, we won’t be affected by the consequences of our pollution, so we will have no motivation to stop polluting.
However, it’s worth noting that most of today’s major pollutants result from the use of fossil fuels and petroleum products; if we stopped extracting fossil fuels, these pollution sources would cease. Moreover, some forms of pollution would become uneconomical in a closed system. For instance, fertilizer and pesticide runoff from indoor agriculture would have to be piped outside instead of simply flowing into the nearest stream. Also, minimizing global climate instability would still be important because it would lower the cost of temperature control in large enclosed spaces.
Furthermore, even people who live with massive amounts of pollution often don’t see any good reason to fight against it, because they see the pollution as a price they’re willing to pay for prosperity. Chinese cities such as Beijing exemplify this tradeoff (Hertsgaard 166). The real problem of pollution is that we may not be able to muster the will to change the systems that produce it before its effects become catastrophic. In case such a catastrophe becomes impossible to avert, it may be worthwhile to mitigate the potential impact on humanity by putting walls between us and the environment.
Another major argument against such walls is the philosophical idea that because humans are part of nature, we simply can’t separate ourselves from it. But our continued pollution and resource extraction is destroying more and more of the natural world; if we can halt these activities, we make it more likely that people will continue to be able to go into the wilderness and commune with nature.
One especially telling argument is that because of the high cost of the enclosures I’ve proposed, only the wealthiest segments of the population will be able to afford to live in them. One answer to this is that the more the technologies needed to create the enclosures are used, the cheaper they will get, and at least some of them will become available to wider populations. Also, the only organizations likely to take on such a large project with such long-term goals are national governments, so in the catastrophe scenario, political pressures would hopefully result in the accommodation of poorer people within the enclosures. In other scenarios, given a stable population, poor people living outside the enclosures would no longer have to expand into wildlife habitat at anywhere near the current rate. And since resource use and pollution per capita is generally proportional to wealth, moving the upper and middle classes into self-sufficient enclosures should eliminate the bulk of the environment-damaging processes. None of these are complete answers to this objection. However, the balance of the arguments suggests that separation is a favorable solution.
Conclusions
Overall, the project to make humanity independent from nature, with the exceptions of energy sources and some land area, appears just barely technically and economically feasible. Creating an air system separate from the global atmosphere is by far the most difficult aspect of the project, which suggests the need for a partial solution: We could continue to depend on the atmosphere while taking every possible measure to avoid disastrous atmospheric changes, including a rapid shift toward renewable energy sources to reduce the impact of global warming. While no longer integrated into the airtight-structure plan, hydroponics would still be a valuable part of the solution because it eliminates agriculture’s impact on the soil, reduces the total land area needed for farming, and can also be implemented in barren regions where the local environmental impact is lower (and where local populations would otherwise depend on imports for food). Total recycling of water and as many building materials and artificial chemicals as possible rounds out the proposal.
Politically and socially speaking, feasibility considerations are much more complex. The governments that would initiate this project, and the corporations they would hire to carry it out, are huge organizations with considerable inertia. Each is deeply invested in a certain way of doing things and has a strong incentive to resist sweeping changes. However, as scientists and the environmental movement continue to work to raise public awareness about the potential for ecological disasters, popular pressure may overcome inertia and force our leaders to move faster toward a safer world.
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