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Discussing climate change via the history of economic thought

This case study is published to accompany the 2023 handbook chapter on Embedding Sustainability in the Economics Curriculum.

An intermediate module on theories of value, growth and distribution at Leeds University examines great thinkers and their role in the development of Economics, and explores contemporary applications of their ideas. One of those studied is Thomas Malthus, best-known for his essay on population (1798) but who also had a full model of growth and distribution. Malthus’ ideas are often cited by those who argue for population control.

In a seminar for the module, students are asked to consider the relation between wages and population in Malthus’ theory, and thereby the components of his population model. The students then consider whether historical (1700-2016) Bank of England data on real wages and population for Great Britain support Malthus’ theory. Students identify periods in which there appears to be some support for Malthus, when real wages were stagnant, and population was increasing rapidly; but they identify clear discrepancies with Malthus’ prediction, such as in the twentieth century when population and real wages both grew.

Finally, we ask students to consider the argument that population control is necessary to prevent or mitigate climate change.

We first ask students to consider the claim in Malthusian terms. The earlier question about Malthus’ population model primes them for this. They spot that climate change could act as a Malthusian positive check on population, via an increased frequency of natural disasters, more wars, and greater likelihood of pandemics. Also, they recognize that climate change effects of more variable and extreme weather events, rising sea levels, and increasing salination of agricultural lands may reinforce diminishing returns to agriculture, as postulated by Malthus. Here we draw on students’ existing knowledge about climate change.

Another prompt to students is to ask why one might argue for population control. They identify a causal chain from population to climate change, via increased consumption and production, and their associated CO2e emissions. We then invite students to consider this argument critically. They typically argue that:-

  1. Technological change may break the link between increased production and increased emissions, or geoengineering projects may be able to reverse some of the accumulated climate emissions. They note that this treatment of technological process echoes criticisms of Malthus’ own theory, which underestimated the scope for increasing agricultural production
  2. Cultural change may break the link between increased population and increased consumption (and hence production), as evidenced by increased consumption of greener products, and greater environmental awareness in line with the concept of the environmental Kuznets curve, a concept some students raised independently of the module material. Again, students note that Malthus faced a cultural context quite different from the present
  3. Population control places the onus for preventing climate change on the individual household, whereas production emissions are created by firms, which therefore have much greater agency than almost all households. These points are often connected with other distributional questions. The population control argument seems to assume implicitly that all population units have the same effects, whereas people born in global northern contexts are likely to have much greater impacts than those from the south, simply by where they are and the cultural norms and systems of production there.

Overall, students typically reject the claim that population control is necessary, because in Malthusian terms, control may not be necessary because climate change could limit population; and because the claim seems to oversimplify the causes of climate change and ignore possible changes in them.

In my experience, this exercise works best when students:

  • have a working knowledge of climate change mechanisms and the links between CO2e emissions and production
  • already feel confident about the basic concepts of Malthus’ model
  • are an internationally diverse group, and are encouraged to introduce contributions about conditions in their home countries

After the seminar we provide notes on the above and invite students to look for data on other countries, and particularly to explore data on emissions. We have sometimes asked students to write an essay on this question in their exam – which has until now been online and 48 hours long. For an in-person exam we would still expect students to bring in ideas from their own research.

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