DSS5101 Chap.6 Kuznets Curves and the Tragedy of the Commons
Kuznets Curves and the Tragedy of the Commons
The original curve and the pledge
The Week 2 lecture introduces the Kuznets curve while discussing the pledge to leave no one behind. Simon Kuznets proposed that inequality rises as countries industrialise, as rural workers move to cities and compete for jobs, and later falls as incomes rise, mobility returns and welfare states develop. Plotted against income, the path is an inverted U.
The lecture adds that since the 1970s inequality has risen in advanced economies and fallen in fast-growing East Asian ones, and concludes that the goals set out to decouple inequality from growth rather than wait for it to resolve.
The environmental version
The environmental Kuznets curve, introduced by Grossman and Krueger in 1991, applies the same shape to pollution: degradation rises with income to a turning point and then falls.
The Week 3 lecture explains it as the balance of three effects. The scale effect raises pollution as output grows with unchanged technology. The composition effect can push either way as some sectors expand faster than others. The technique effect lowers pollution as production becomes cleaner and citizens demand a cleaner environment.
Panayotou’s work, cited in the lecture, links degradation to income bands: worst below about $1,000 per person, changing rapidly between $1,000 and $3,000, and entering a second transformation above $10,000.
Why carbon dioxide does not follow
The evidence for the curve is strongest for local pollutants such as sulphur dioxide, which fell from 1980 to 2010 in every region except Africa and Asia.
For carbon dioxide the lecture quotes Yandle and colleagues finding no support at all. Local pollutants harm the people who produce them, so cleaning them up pays off locally as incomes rise. Carbon dioxide does little local harm and accumulates globally, so each country gains little from acting alone.
That is a tragedy of the commons: every party finds emitting cheaper than cleaning up, so the shared atmosphere degrades and all are left worse off.
What this chapter covers
- 01
The inequality curve and rural-to-urban migration
- 02
Why the goals refuse to wait for inequality to fall
- 03
The environmental curve and its three effects
- 04
Panayotou's income bands
- 05
Local pollutants against carbon dioxide
- 06
The tragedy of the commons and the pollution haven
Worked example · free
Decomposing a change in pollution into scale and technique
- 1Express the scale effect as a multiplier.
- 1Express the technique effect as a multiplier.
- 3Combine them and interpret.
Key terms
- Kuznets Curve
- The hypothesis that income inequality first rises and then falls as a country develops, tracing an inverted U against income.
- Environmental Kuznets Curve
- The hypothesis that environmental degradation rises with income up to a turning point and then declines.
- Turning Point
- The income level at which a pollutant's rising trend is hypothesised to reverse, estimated for some local pollutants between $7,300 and $18,000 per person.
- Scale Effect
- The rise in pollution that follows from producing more output with unchanged technology and economic structure.
- Technique Effect
- The fall in pollution that follows from cleaner production methods and from citizens demanding a cleaner environment.
- Tragedy of the Commons
- A situation in which each user of a shared resource gains from overusing it while the costs are spread across all, so the resource is degraded.
- Pollution Haven
- A country that receives polluting industry relocated from richer countries, making the richer country's decline in pollution partly an export.
Kuznets Curves and the Tragedy of the Commons FAQ
What is the Kuznets curve in simple terms?
It is the idea that inequality rises in the early stages of industrialisation, as workers leave farms for cities and compete for jobs, and then falls once incomes are high enough for mobility and welfare states to spread. The lecture treats it as a hypothesis that recent evidence has challenged.
What does the environmental Kuznets curve claim?
That pollution rises as an economy grows until average income reaches a turning point, after which it declines. In its strongest form it implies that growth itself solves pollution, a claim the course asks you to test pollutant by pollutant.
Why does the curve not hold for carbon dioxide?
Carbon dioxide causes little local harm and accumulates in the global atmosphere, so a country gains little from cutting it alone. Local pollutants such as sulphur harm residents directly, which is why cleaning them up becomes worthwhile as incomes rise.
What are the scale, composition and technique effects?
They are the three forces behind the curve. Scale raises pollution as output grows, composition moves it either way as some sectors expand faster, and technique lowers it as production becomes cleaner. The curve turns down only when technique outweighs scale.
Is the downturn automatic once a country is rich enough?
No. The technique effect depends on regulation and public demand. The reading from the International Growth Centre argues that policy can bring cleaner technology forward, so developing countries could follow lower and flatter curves than today's rich countries did.
What is a pollution haven?
A country that attracts dirty industry relocated from richer ones. It can make a rich country look as if growth cleaned it up when part of the pollution has only moved, although one study cited found offshoring explained only a small share of the fall in US manufacturing pollution.
Assessment move
Draw both curves from memory and label the three effects on the environmental one. Then take any pollutant in the news and decide whether it is local or global before predicting its path; that single distinction settles most questions about where the curve applies.
Working through Kuznets Curves and the Tragedy of the Commons in DSS5101? Sia is AskSia’s AI Environmental Science tutor — ask any DSS5101 Kuznets Curves and the Tragedy of the Commons question and get a clear, step-by-step explanation grounded in how DSS5101 is taught and assessed. Read this chapter free, then take your hardest questions to Sia.
