Overpopulation or Underpopulation? Toby Ord Programme on the Impacts of Future Technologies Oxford Martin School University of Oxford

Transcription

1 Overpopulation or Underpopulation? Toby Ord Programme on the Impacts of Future Technologies Oxford Martin School University of Oxford

2 Introduction Benefits of population Costs of population How things might change

3 Pessimism about Population Thomas Malthus, 1798 Paul Ehrlich, 1968

4 A more balanced view Population is not just a negative It can also bring many benefits We need to weigh the costs against the benefits There may be an imperative to limit population There may be an imperative to increase it Laying a foundation for future discussions

5 Introduction Benefits of population Costs of population How things might change

6 The Information Economy Hammers vs Songs Made from matter Fundamentally just a pattern Each one must be laboriously made Must be laboriously made once Then can be very cheaply copied Benefits one person who desires it Benefits all people who desire it Value is independent of population More valuable with more people

7 The Information Economy Increasingly many goods are in the information economy Novels, poems, films, songs, recipes Science, inventions, designs Software All academic research With more people, we get more value from creating these If you doubled the size of the population: We could get the same amount of these things with more free time Or we could each get much more of these goods

8 Complex Goods Hammers vs Computers Made from iron Made in a smithy Made from a long list of exotic elements and components Made in a very complex factory Could be made by a small population Requires a huge population to make

9 Complex Goods We get a lot of benefit from complex technologies Getting these with a much smaller population is either: Impossible Or would have taken many more centuries Either way, we get these goods now because of population What goods will we miss out on if we limit population?

10 The benefits for the new people You are population too! Is it good that you exist (ignoring effects on others)? What would we miss out on with 1 billion fewer people? Current British population is 0.06 billion Entire population who have ever lived in Britain from prehistoric times onward is less than 1 billion Was there something good about having all of this life and activity that people strived for over the centuries? Should we blithely give up things of this magnitude?

11 The benefits for the new people How to assess the value of a population? Henry Sidgwick, 1874 Derek Parfit, 1984

12 The benefits for the new people Average vs Total Look at the average wellbeing Sum up everyone s wellbeing Good to add a life if it has greater than average wellbeing Good to add a life if it has positive wellbeing More likely to resist increasing population More likely to advocate increasing population Sidgwick s preferred theory

13 The benefits for the new people + average + total average total

14 The benefits for the new people average + total average + total Better for some, Worse for none, Bad for none

15 The benefits for the new people Total view sometimes implies an obligation to have more children But so do almost all other views There is much more that can be said here Average vs Total vs Actual vs Necessary vs

16 Introduction Benefits of population Costs of population How things might change

17 Limits There are many potential limits to population growth: Food production Fresh water Energy Atmospheric CO 2 Other natural resources In practice, these are not sharp cut-offs But they can reach points of rapidly increasing costs We should mainly focus on the most limiting factor If factor X limits us to 10 billion and factor Y limits us to 15 billion Then factor X warrants much more of our attention

18 Soft Limits & Hard Limits Are we near a limit on food production? Yes: We can only just feed the current population, and have little arable land left to expand No: Meat production uses much more land per eater than vegetables, so we could support twice as many people if we ate less meat

19 Soft Limits & Hard Limits Both are right in a sense With business as usual, global food shortages may soon occur With sensible management, they won t We are not near the hard limit on food We are near a soft limit We should start thinking of ways to change behaviour

20 Distribution of Population Conditions in different countries vary greatly The old population was not spread evenly The new population will not be spread evenly These factors combine to complicate things greatly Political upheavals Migration Regional shortages Uneven power Need to be very careful about our intuitions

21 Introduction Benefits of population Costs of population How things might change

22 Technological Change Erlich was wrong when he claimed: In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now. Green Revolution High yield cereals, irrigation, fertilizers, pesticides Increased wheat yields per hectare by a factor of 3 Norman Borlaug estimated to have saved > 200 million lives

23 Technological Change Technological changes could expand limits Genetic engineering of crops, or new farming methods such as aquaculture may ease food limits Cheap, clean energy would relax many limits at once In the long run colonizing other planets Technological changes could increase benefits Moving more things into the information economy Developing new complex goods

24 Social Change If we could cooperate better, we could greatly expand many limits: Eating less meat Using less water Using less CO 2 Using less energy Could double all of these limits with little real cost

25 Conclusions Questions about population targets are very serious and require a sober discussion The benefits must be weighed against the costs It is possible to have underpopulation with an imperative to increase our population Information goods and complex goods are two key reasons to have a higher population The intrinsic value of the new people is a third reason We must distinguish between hard and soft limits There could be great benefit in overcoming the limits with technological and social change

26 Questions? Comments?