Hard SF : Science Issues : Can Space Colonization End Overpopulation?
Some space enthusiasts and SF readers believe the (or at least a) solution to Earth's population pressures is to find new places for people to live beyond the Earth. The point of this article is not to consider whether humans can, will or should eventually find additional homes not on planet Earth. It is only to deal with issues related to using colonization of space as a means to end the population crisis on Earth in a timely manner.
According to the US Census Bureau's estimates the human population of Earth as of Jan. 1, 2008 was over 6.6 billion. Their population figures indicate the world population is currently growing by over 70 million people each year.
Population does not grow at the same number of people each year. As the population gets larger, there are more people to have babies, so the number of new babies each year tends to be greater than the number the year before. (Longer lifespans also contribute to population growth.) Assuming humans do not begin to reproduce at a slower rate, as time goes by the annual increase in population will rise further and further above 70 million.
Let us assume a 1% annual rate of increase in the human population (this is actually somewhat less than it currently is). At that rate, in 50 years the Earth's population would be about 10.8 billion and increasing by about 108 million people in a year.
Although I seriously doubt that we will be capable of transporting tens of millions of humans off the Earth in as short a time as 50 years from now, let us assume we will. Even assuming that from 2028 to 2058 we would be able to transport 1 million per year off-planet, that would not have substantially changed the situation.
So imagine we are in 2058 and we can transport off-planet just as many people as the amount by which Earth's population would have grown. Doing so will merely stabilize the world population at about 10.8 billion - not necessarily a comfortable number.
It would be necessary to transport 108 million people off-planet every year. Assuming that by 2058 we are able to build and use colony ships that will hold 1000 people each, that means 108,000 such colony ships every year. That comes out to about 295 each and every day of the year - more than 12 every hour. If these ships are just ferrying people to a colony and returning to Earth to pick up another group and if the colonies average a day’s journey from Earth, we would need 2 days worth of ships – that’s 590 ships capable of carrying 1000 people. The number of ships must be increased if the journey time to the colonies is greater. If these are “colony ships” that will never return to Earth, that’s 108,000 new ships per year.
This is a mind-bogglingly large project by itself. However, it is only part of what would be required. Every ten years you would need some habitable place for another billion people. We simply don't have any planets or moons in this solar system where you can just drop people off with tents and have them live like Daniel Boone. You have to either terraform a world, manufacture artificial habitats for all those people or find habitable worlds in other star systems. Any of those are going to require significant time and resources.
All the manufacturing of hundreds or thousands of huge colony ships and creating habitable places to go will have an impact on the fragile environment and limited resources for a planet with 11 billion humans. As the population increases, demand for resources for those remaining on Earth will become greater and we can expect fierce competition over how much of those resources should go to helping everyone on Earth today and how much should go to projects intended to help a minority that may be leaving the planet in the future.
In theory, mining and manufacturing could be carried out off-planet - but first it would be necessary to invest time and resources to build off-planet mining and manufacturing. And while large amounts of resources are being used to bring large-scale off-planet mining and manufacturing into being, there will be less resources to be spent on transporting people to other places.
It seems highly unlikely that by 2058 we will have colony ships that can be launched from Earth's surface carrying 1000 people. How will we get 295,000 people from Earth's surface to space every day? To take 295,000 people each day to orbit using chemical rockets would require so many launches that it would be an environmental nightmare by itself. We would have to invent, plan, construct and put into operation large numbers of some new type of surface-to-space vehicle that we could launch hundreds or thousands per day.
Even assuming we were capable of building a "space elevator" it would be yet another massive project demanding time and resources. One "space elevator" won't be able to take 12,000 people (plus supplies) every hour. Suppose it could carry 500 people at a time. Suppose it can be loaded, take them up to the top, be unloaded and come back down to Earth for another group in only 10 minutes. That would only be 3000 people per elevator per hour. There would have to be at least four space elevators.
Suppose, in order to accomplish all of these necessary projects it took 75 years rather than 50. At a 1% population growth rate, the Earth's population in 2083 would be 13.8 billion with 138 million more each year. Suppose, all of this took 100 years. At a 1% rate, by 2108, the population would be 17.7 billion. It would be necessary to take 177 million people off-planet every year just to maintain Earth at 17.7 billion. If we consider 17.7 billion too many and want to reduce Earth's population, it would be necessary to transport even more millions to other habitats.
I do not believe our current population growth will permit us enough time for this to be a practical solution. It seems that by the time we may be able to accomplish the technological marvels that would be required, the Earth's population would already be at too great a state of crisis. Other means are needed that can help us avoid such a huge population which can be implemented in a shorter period of time.
A project on the scale described above would be so astronomically expensive and involve so many people that issues of international politics and economics are unavoidable.
To take on a project to emigrate 100 million people per year (with an appropriate number of people leaving each individual country) seems to be an effort for an international organization with loyalties to humanity as a whole, not to the interests of specific nations, races, religions or other groups. We don't really have an organization that fully fits the bill, and that is because those who would pay the bills for an organization of that scale would expect to get advantages for their nation or group in exchange for their funding.
The UN, as it exists today, has never taken on such expensive and long-range projects. Also, there are issues of the UN's organization. The General Assembly, where all countries participate, has little power. The real power is in the Security Council. The real power within the Security Council is the permanent members - each of which has the right to individually veto any proposal it finds inconvenient. The permanent members (except China) are developed nations which have more money, but less overpopulation. So, the developing nations with the greatest overpopulation problems are more or less powerless in the UN. Generally, these nations don't challenge this arrangement too strongly for fear of having foreign aid from developed nations reduced. The UN can't take on any project even of considerably smaller scale without the cooperation of every single developed nation holding a permanent seat on the Security Council. And those nations do not tend to act selflessly on behalf of humanity, especially if they are paying for the project.
It doesn't seem a single country could afford to pay for the entire 100 million people per year. Even if a single country could afford it, a single country won't ship out 100 million of only that one country's people each year. To send 100 million per year to space colonies means people being sent from a number of countries. The country paying the bill will either send people from countries that are reimbursing them for the cost of the project, or it might help countries with whom it has favorable relations without charging them. Either way, it would be unlikely to result in overpopulation being relieved in an optimal way where it is needed most.
If a single nation were to establish a space colonization program to reduce population pressures, it would be cheaper and more immediately beneficial for that one country to only emigrate its own nation's excess population to a space colony run by that one nation. (That is, it’s not sending out 100 million per year from the world, but maybe a few million just from the one nation’s population.) However, if it sends out millions of its people to space colonies while the rest of the world lacks that option, the rest of the world will be jealous and suspicious of that country's plans.
What single country might choose a project massive enough to even keep down its own national population? The US is not faced with the overpopulation some nations are. China has an especially large population, has shown interest in population control (the one child law) and is a major power. However, if China began a project to send millions of Chinese into space, the West would be alarmed at the potential political, military and economic implications. Such a project by India might not alarm the West as much, but India is probably not in as good a position as China to attempt it. In reality, probably any single nation taking on such a project would raise concerns among some influential nations. No developed nation would be unconcerned at the prospect that some other nation was getting a head-start colonizing space, would have an opportunity to take the most favorable locations for itself, might claim the most valuable resources in the solar system, and might gain a military advantage.
Some might suggest that some of the political obstacles could be circumvented if private companies attempted to build massive space colonization projects. Private companies don't have the kind of money and resources "world power" nations do, so there are questions as to how many people they could actually emigrate to space colonies. Assuming they could, the initial investments in building both the habitats and the transport from Earth to the habitats would be mind-boggling. In order to get back that investment and make a profit, they would expect to have full control over the colonies. Between the fact these colonies would be in locations not currently settled by a country and the degree of control the company would want, the colonies would effectively be new nations - and might very well declare themselves to be that. This prospect will worry some nations, which may lead them to try to hinder or prevent this option.
Suppose an international organization ran a project to emigrate appropriate numbers of people from each of Earth's nations. Would it build separate habitats so that people coming from a particular nation went to a habitat for that nation? Is that practical or desirable? If that was not done, the space colonies would not be linked to specific nations on Earth. Would they all constitute a single vast new nation associated with this international organization? Would they be new nation(s) independent of the international organization? What form of government would run the colonies - and who would decide that question? Similar questions would be raised if a single country (or consortium of developed nations) were to run the project.
Regardless of whether it is an international organization, a single nation or private companies, there's the question of who, occupationally, they would choose to have emigrate. If we had an empty Earth-like planet available, it would be possible to send Earth's excess of unskilled workers with just enough tools to start 18th century-style colonial farming. But that's not an option. Until terraforming or interstellar exploration provides such an option centuries from now, the people would have to go to artificial habitats. The space colony projects will be massive enough without attempting to have them include enough Earth-like farm lands and rice paddies to feed millions of people. Even the food producing jobs will not be in the form rural people from developing nation are familiar with. And many of the jobs will be associated with maintaining an artificial habitat and the professions related to that kind of technological setting. A significant number of the emigrating population would have to be skilled professionals - people Earth will not be as willing to see leave. Today, developed nations recruit skilled professionals from developing nations to move to the developed nation. Considering that, can we expect developed nations to contribute most of the skilled professionals to the space colonies and allow the developing nations to contribute only unskilled rural labor? Can we expect developing nations to contribute their precious supply of skilled professionals, while limiting the number of unskilled workers who go?
There are so many issues other than the technological ones that will play a role in how space colonization takes place.