On this episode of X10, Nicola describes how, even if longevity does lead to a global rise in population, near-future technologies may support this growing population.
Sources and Further Reading
This episode was particularly tough to research and write, and it was only an overview! Below, you’ll find all the sources that were used and links to other sources that you might find interesting to read. It’s quite possible that future X10 episodes will focus on some of the concepts mentioned in this overview, or even those that were left out entirely.
- Sources and further reading on carrying capacity
- Pengra, B. (2012). One planet, how many people? A review of earth’s carrying capacity. UNEP Global Environmental Alert Service (GEAS).
- Cliggett, L. (2001). Carrying capacity’s new guise: folk models for public debate and longitudinal study of environmental change. Africa Today, 3-19.
- Hopfenberg, R. (2003). Human carrying capacity is determined by food availability. Population and environment, 25(2), 109-117.
- Cohen, J. E. (1995). Population growth and earth’s human carrying capacity. Science, 269(5222), 341-346.
- For an example of non-human animals able to affect their environment’s carrying capacity, see here.
- Land cover As said in the episode, all estimates for the total surface of urban and built-up areas that we could find ranged between 0.6 and 1.5 million square kilometers.
- According to Our World in Data, land cover is as follows:According to OWID, the total urban and built-up areas is about 1.5 million square kilometers; the source OWID cites is FAO, but as far as we could tell, the latest FAO data says that the total urban land area is 79,183,484.6 hectares, which is less than 800,000 square kilometers. (Select Artificial surfaces under items, World+ (Totals) under regions, 2017 under years, and Area from MODIS under elements.)
- Urban land estimates by OECD are closer to FAO’s: 767,681.05 square kilometers.
- This Nature paper computed projections of the urban land throughout this century; for 2020, the range is between 0.6 and 1 million square kilometers, more or less. The full paper reference is: Gao, J., & O’Neill, B. C. (2020). Mapping global urban land for the 21st century with data-driven simulations and Shared Socioeconomic Pathways. Nature communications, 11(1), 1-12.
- Estimates of agricultural land (on FAO’s website, for example) tend to agree with OWID’s stated 50% of the habitable land.
- Environmental impact of food production
- OWID’s relevant entry was the main source used in this episode; in turn, OWID’s main source was a 2018 review: Poore, J., & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science, 360(6392), 987-992.
- Wikipedia’s entries on the environmental impacts of meat production, agriculture, fishing, and irrigation make for good further reading material if taken with a grain of salt and you have the patience to double-check sources. (We did find inaccuracies some times.)
- Cultured meat
- A general overview can be found here.
- New Harvest’s article on the world’s first cultured-meat burger can be found here; the video of the first tasting of the burger is here.
- The study assessing the impact of cultured meat is Tuomisto, H. L., & Teixeira de Mattos, M. J. (2011). Environmental impacts of cultured meat production. Environmental science & technology, 45(14), 6117-6123.
- A 2018 paper on the state of the art of cultured meat can be found here; the reference is Gaydhane, M. K., Mahanta, U., Sharma, C. S., Khandelwal, M., & Ramakrishna, S. (2018). Cultured meat: state of the art and future. Biomanufacturing Reviews, 3(1), 1.
- As promised, here’s a non-exhaustive list of companies working on, advocating for, or financing research on, cultured meat and fish:
- Vertical farming
- An introductory PDF on this subject can be found here; we also used it as a source.
- A paper comparing hydroponics and traditional farming methods to grow lettuce is here: Barbosa, G. L., Gadelha, F. D. A., Kublik, N., Proctor, A., Reichelm, L., Weissinger, E., … & Halden, R. U. (2015). Comparison of land, water, and energy requirements of lettuce grown using hydroponic vs. conventional agricultural methods. International journal of environmental research and public health, 12(6), 6879-6891.
- This TED talk by Stuard Oda on vertical farming might interest you as well.
- This chapter on a book about urbanization and sustainability discusses aeroponics: Mytton-Mills, H. (2018). Reimagining Resources to Build Smart Futures: An Agritech Case Study of Aeroponics. In Smart Futures, Challenges of Urbanisation, and Social Sustainability (pp. 169-191). Springer, Cham.
- Again, Wikipedia is an okay source for further reading.
- A video is worth more than a thousand words, and so are three: check out what SciShow, Kurzgesagt, and It’s Okay to be Smart have to say on the topic of GMOs.
- Statements on the safety of GMOs can be found… everywhere.
- https://www.pps.net/cms/lib/OR01913224/Centricity/Domain/3337/peer reviewed meta study on GMOs copy.pdf
- Panchin, A. Y., & Tuzhikov, A. I. (2017). Published GMO studies find no evidence of harm when corrected for multiple comparisons. Critical reviews in biotechnology, 37(2), 213-217.
- The impact of GMOs has been evaluated in this 2014 paper: Klümper, W., & Qaim, M. (2014). A meta-analysis of the impacts of genetically modified crops. PloS one, 9(11).
- Nuclear fusion
- If you want to learn more about fusion in an easy way, look no further than Kurzgesagt and Answers with Joe; Joe also has a video on fusion breakthroughs.
- A very good official source about fusion is ITER’s website—the International Thermonuclear Experimental Reactor.
- You might be interested in this position paper on fusion by the European Physical Society as well as this general paper on the subject
- Some of the information in the episode also came from this book: McCracken, G. M., McCracken, G., & Stott, P. (2005). Fusion: the energy of the universe. Academic Press.
- Here comes the non-exhaustive list of nuclear fusion projects, and institutions and companies working on nuclear fusion:
- Things that were left out
- Nuclear fission is already better than fossil fuels as an energy source, even though it is more dangerous than fusion. Here’s three great Kurzgesagt videos on nuclear fission: one, two, three.
- Joe Scott’s playlist on renewable energy may interest you.
- Water scarcity is a serious problem. The World Economic Forum included it in their list of the largest risks we’ll face by 2030, and a 2016 paper estimated that about 4 billion people in the world already face severe water scarcity. (Mekonnen, M. M., & Hoekstra, A. Y. (2016). Four billion people facing severe water scarcity. Science advances, 2(2), e1500323.) We need to keep in mind that, if things like cultured meat and vertical farming become commercially viable, that alone can be a game-changer, given that we use the majority of freshwater withdrawals for agriculture. Still, experts do have possible solutions in mind, among which desalination, water conservation strategies, and water recycling.
- Whether there will be enough jobs for an increasing number of people is a good question; it’s hard to tell if and how much the nature of work will change by the time life extension becomes widespread. We will probably talk about this in future episodes; for now, a proposed solution to the issue is UBI, or universal basic income, a flat money sum that governments could pay to their citizens, no strings attached. Some love the idea, some hate it; if you haven’t decided yet, this video by Joe Scott may at least help you know more about it.
In the previous episode of X10, we saw that empowering women across the world and reducing the mortality rate among children are our best weapons to reduce population growth, because they have a profound impact on the overall fertility rate.
Still, for the sake of argument, say that life extension therapies that slow down or even reverse aging were to cause such a big increase in population that nothing we try actually manages to keep our numbers low.
At that point, would we be too many people for this planet? How many is too many? Whatever that number may be, is it set in stone, or can we change it? And, if so, how?
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The maximum number of individuals of a population that an environment can support is called the environment’s carrying capacity. This concept is widely used in ecology for non-human species, and, essentially, it relates the resources available in an environment to the populations of an animal species in that environment.
The basic idea is that, if a population exceeds its environment’s carrying capacity, its members will start dying off until the population shrinks down below the carrying capacity.
As long as we’re talking about animal populations, the carrying capacity of their environment depends only on things like space, food, water, and so on. When it comes to humans, it gets much more complicated, as it is reflected in the wild variety of human carrying capacity estimates that have been proposed, which range anywhere from less than a billion people to over a thousand billion people.
Most estimates fall somewhere between 8 and 16 billion people, but none of them are set in stone, and scientists are aware that they need to be taken with several grains of salt. As a matter of fact, this concept has been criticized over the years, because while it works well for animals, the interaction between humans and the environment is much more complicated, and it might simply not be very well captured by the definitions of carrying capacity.
The high variability in the different carrying capacity estimates depend in no small part on the method used to calculate them, but the problem is also that our technology can change the way we interact with the environment, and thus its human carrying capacity, in unpredictable ways. That’s something that just doesn’t happen to other animals.
Before the third agricultural revolution of the mid-1900s, feeding a population as large as today’s was impossible; without the changes in production techniques that occurred back then, the Earth could not have supported the almost 8 billion people that exist now. That’s an example of humans increasing the carrying capacity of the planet.
One of the catches is that we rely heavily on fertilizers to grow our food, and fertilizer production requires a lot of natural gas. Natural gas exists in limited supply, and producing more and more fertilizer for the needs of a growing population will consume it. So, natural gas is an example of a constraint on the human carrying capacity of the planet, at least for as long as our production methods don’t change. If we could grow food without fertilizer, the amount of natural gas would no longer be a constraint.
That’s why carrying capacity estimates aren’t final: it’s very hard to predict when a new breakthrough will allow us to do more with less or when disaster might strike and reduce our ability to support ourselves.
So, what can we do to make sure that, even if life extension does significantly increase our population, we will always be able to feed everyone without screwing over the planet in the process?
Let’s take one step at a time. In terms of space only, could we fit more people on this planet? In principle, yes, absolutely. Estimates of the current total size of urban and built-up areas in the world, including infrastructure, vary a little depending on the source, but they range between 0.6 and 1.5 million square kilometers.
That’s not a lot: it’s between 0.5 and 1.4 percent of the total habitable land of the world, which is around 104 million square kilometers, give or take a few million square kilometers.
Estimates of the total land dedicated to agriculture, that is both livestock and crops, are much more similar to each other and gravitate towards 50 million square kilometers.
That’s about half of the total habitable land; it’s a lot, and it has a number of negative environmental consequences that we’re gonna get into in a minute, but speaking of space, if science and technology could help us reduce the amount of land needed to grow food even by, say, ten percent, that would be a lot of land where all our existing cities, towns, villages and infrastructure would fit several times.
So, it’s not like we don’t have space for more people; we do, if only we can figure out a way not to use so much of it to produce our food. That’s a challenge, of course, because the implication is that we need a way to grow food for more, maybe many more, people than we have today with less land than we do now.
Of course, space isn’t the only problem, and in fact, it’s probably the least of our concerns. The really big problem is that food, energy, and water are intertwined in a complex way. For example, in order to produce food for everybody, we need massive amounts of energy and water. More people need more food, which means that more energy and water are used to produce it, and we get more of the side effects caused by their use.
The magnitude of these effects varies depending on the food being produced. On average, most meats, dairy, and farmed seafood require far more land per kilogram than the vast majority of vegetables.
They also require more water per kilogram, in the order of thousands of liters, and they cause far more greenhouse gas emissions. Greenhouse gases, or GHGs, are what is causing our planet to abnormally warm up, and food production in general accounts for more than a quarter of the total greenhouse gas emissions in the world.
While crops cause lower GHGs emissions than livestock and fisheries, it’s still a solid 27%. Land use also increases the level of GHGs in the atmosphere: for example, forests are natural carbon “sinks”, meaning that they capture carbon dioxide, a GHG, as part of their respiration process; but to make more room for crops and pastures, we need to cut more and more trees, so more carbon dioxide stays around.
The negative effects of food production are too many to list or discuss all in a single episode; you can find out more in the description below, but the point is, these effects are problematic enough now. We don’t want to know how much worse they’ll be if and when the population will be much larger, but we would like to know how we can prevent them.
Thankfully, there are some promising technologies in the works that may revolutionize the way we grow our food, produce our energy, and live our lives. Their potential benefits are so huge that they’re well worth embracing regardless of the size of our population.
Cultured meat is meat that doesn’t come from a slaughtered animal. It’s grown in a lab using stem cells from an animal, but there’s no killing involved. It used to be the stuff of science fiction, but nowadays, it’s not even news anymore, and soon it may be on supermarket shelves. It’s just a matter of cost and scalability.
The first cultured-meat burger was created in 2013 by Dr. Mark Post from Maastricht University and his team. It was actually publicly tasted in 2013, and the people who ate it essentially said it passed almost for the real thing.
Cultured meat started off expensive: Dr. Post’s burger cost nearly €250,000 and took over two years to prepare, but in a 2015 interview, he said they expected the product to be commercially viable within ten years and that the cost could be reduced down to 8€ per burger.
Dr. Post is far from being the only one working on this. There are several companies working to bring cultured meat to our tables, including Dr. Post’s, and they all have an interest in driving the cost down as much as possible. You’ll find a list of companies in the description below. Some of them are working on cultured fish, too.
The benefits of cultured meat could be enormous: a 2011 study estimated that producing 1000kg of cultured meat could require between 7 and 45 percent less energy, cause 78 to 96 percent less greenhouse gas emissions, use 99 percent less land, and 82 to 96 percent less water than traditional meat.
In addition, lab-grown meat carries far less risk of diseases because it’s created in a laboratory environment, and it could be custom-made to be more nutritious or contain less cholesterol, for example. Not to mention that it would be cruelty-free.
Traditional crops have a smaller environmental impact than meat or fish, but they still have one, and vertical farming might help reduce it. Vertical farming is the practice of growing crops in vertically stacked layers, with no soil involved.
A vertical farm can be set up in a city building, where it takes far less space than a traditional farm, precisely because it extends upwards, not horizontally. To grow crops without using soil, vertical farms use techniques such as hydroponics, aquaponics, and aeroponics.
These techniques are similar to each other, and the basic idea is that the plant roots are submerged in a liquid solution containing all the nutrients the plants need. Hydroponics uses up to about 70% less water than conventional farming methods; an aeroponic farm, where the liquid solution is misted in air chambers where the plants are suspended, uses even less water.
Aquaponic farms combine crops with basically fish tanks in order to mimic a natural environment where the wastewater of the fish is continuously recycled. The plants absorb nutrients from it, making it reusable for the fish.
Besides lower land and water usage, vertical farms have other advantages. They are not affected by the weather, because everything happens indoors; they have little to no pest problems, because of the strictly controlled environment; and they’re less disruptive to plants or animals, because they are built in cities.
Vertical farms also produce fewer CO2 emissions than normal farms, because there are no large, fuel-burning farming machines involved. Heating, cooling, and lighting are artificial, so your crop isn’t dependent on the geographic location of the farm itself or on the time of the year.
All that glitters is not gold, though, and while extremely promising, vertical farming isn’t going to replace traditional farming just yet. For one, vertical farms have higher startup costs, because urban locations are expensive and because of the artificial light and temperature control systems.
The power source used should also be factored in: if vertical farms got their power from coal, they wouldn’t be all that ecological. At present, only a limited number of different crops are profitable to grow in a vertical farm, and those that require insect pollination need extra work, because insects are just not part of the equation in an indoor farm, and pollination needs to be done by hand.
Still, as the world moves towards greener energy sources and land and water scarcity drives demand, vertical farms could become a more profitable and viable solution to feed a growing population in a more sustainable way.
Genetically modified organisms, or GMOs, are another great tool in science’s toolbox that could change the way we grow food. As a matter of fact, people have been manipulating the genome of crops ever since agriculture existed, only they did it manually through selective breeding and cross-pollination.
These techniques allowed to select plants with more desirable traits, like resilience to droughts or pests, and larger yields, but they were extremely slow and imprecise. Through modern genetic engineering techniques, the same thing can be done with extreme precision and much more quickly.
The benefits are many: GMO crops could be engineered to have longer shelf life, to resist pests and adverse environmental conditions, and produce larger yields. A meta-analysis of the impact of GMO crops published in 2014 showed that they reduce the use of chemical pesticides by 37% while increasing crop yields by 22% and farmer profit by 68%. That’s not peanuts.
Even though GMOs have long been at the center of a safety controversy, the general scientific consensus is that they’re no more dangerous to human health than conventional crops. The debate over this and other concerns is still raging, though, to date, there’s no conclusive evidence that GMOs may be generally bad for us or the environment.
A growing population means a growing need for energy, particularly clean energy. Burning fossil fuels to satisfy the energy needs of our current population or those of a much larger, future one would be essentially madness.
Better options exist already today, but it would be impossible to talk about them all in a single episode; you’ll find more information about them in the description below, but right now, we’re going to briefly talk about nuclear fusion.
Nuclear fusion is the opposite of nuclear fission, which is the process that creates the nuclear energy that everyone knows about. In nuclear fission, atomic nuclei split in an energy-releasing chain reaction; in nuclear fusion, atomic nuclei are fused together, releasing much more energy than fission in a much safer way.
Fusion is what powers stars, and in stars, the reaction is kept going by the star’s enormous gravity and pressure. Recreating fusion in a lab requires extremely precise and controlled conditions, such as temperature and pressure, and the slightest variation would result in the reaction coming to a halt. That’s the abridged version of why fusion reactions can’t lead to the same kind of devastating explosions that can occur with fission reactions.
Possible fusion fuels are isotopes of hydrogen—”variations” of it that have a different number of neutrons in their nuclei—of which the primary one, deuterium, is easily accessible and abundant. The only waste products of nuclear fusion are helium, which is completely harmless, and tritium, which can be dangerous but decays fairly quickly.
Because of fuel availability and the high energy yields, fusion is considered to be the energy of the future, potentially able to satisfy all our foreseeable needs for centuries to come. The catch is that controlled fusion is not easy to achieve, and while several initiatives around the globe have made considerable progress over the past decades, we’re not yet at the point of using fusion energy to power the world.
However, scientists are confident that it can be done, probably during this century, and many are working on it. You’ll find a list of companies and institutions working on nuclear fusion in the description.
There certainly are other things that would be worth discussing in terms of managing the needs of a larger population: water scarcity, for example; the employment of other forms of renewable energy production; and last but not least, the economy of the future: will there be enough jobs for everyone? Will there be jobs as we know them in the first place? These are all very interesting questions, but as we can’t possibly discuss everything in a single episode, you’ll find further reading material about them in the description, and we’ll probably make separate episodes about them in the future.
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Thanks again for watching. See you soon with the last episode of X10’s overpopulation series, where we’ll talk about something radically different: ethics. See you then, and take care!
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