Economic, Social and Environmental Sustainability

What is sustainable development?

For most of the twentieth century, success was measured by one number: growth in output. Sustainable development asks a harder question: can we keep improving living standards without using up what future generations will need?

Notice the two time periods: now and later. A policy that boosts income today but damages rivers, fish stocks or the climate for the next 30 years is not sustainable, however good this year's GDP looks.

The idea links directly to opportunity cost. Using a resource today means it is not available tomorrow.

The three pillars

Sustainability rests on three connected pillars.

The pillars are interconnected. Poverty can push people to overuse land or fish stocks. Pollution harms health, which reduces productivity. A weak economy leaves little money for the environment or for social protection. A policy often helps one pillar and harms another, and that trade-off is what examiners want you to discuss.

Measuring sustainability with indicators

To judge sustainability you need data. Each pillar has its own indicators, and you should be able to calculate and interpret them.

Percentage change

A fall in emissions is an improvement in environmental sustainability, because there is less pressure on the climate.

Growth per head and emissions intensity

Two quick approximations help when growth rates are small:

• Growth of GDP per head $\approx$ growth of GDP $-$ growth of population.

• Change in emissions per unit of GDP (emissions intensity) $\approx$ growth of emissions $-$ growth of GDP.

Measuring inequality

The Gini coefficient runs from 0 (everyone has the same income) to 1 (one person has everything). A rise means more inequality.

The at-risk-of-poverty rate is the share of people living below 60% of median income.

A simple measure from income-share data is the quintile ratio: the income share of the top 20% divided by the share of the bottom 20%.

Externalities and policy for sustainability

Why do markets often fail the environment? Because many costs fall on people who are not part of the transaction.

Take a dairy farmer in Tipperary who expands the herd by 20%. The private benefit is extra income of €15,000 a year. The external cost is nitrate run-off into local rivers, which harms water quality, fish and the people who use the river. The farmer's own costs (feed, labour) are counted, but the river damage is not. So the farmer may ignore it, and the market produces more than is best for society.

The market quantity is above the socially best quantity. Policy tries to close that gap.

Policy tools

Carbon tax: internalising the externality

A carbon tax adds a charge per tonne of CO₂. This raises the price of fossil fuels, so their private cost moves closer to their social cost. This is called internalising the externality. Consumers and firms have an incentive to use less carbon-heavy fuel.

Effects to discuss:

• Environmental: lower fuel use and lower emissions. The effect is bigger if demand is elastic, for example when good alternatives exist.

• Social: the tax is regressive in effect. Low-income households spend a larger share of their income on home heating and transport, and rural households often have no alternative to the car or oil boiler. Part of the revenue can be recycled through increases in social welfare payments, fuel allowance, or retrofitting grants to protect these households.

• Economic: higher energy costs can reduce competitiveness for energy-intensive firms, and may slow growth in the short run. In the long run, investment in efficiency and renewable energy can support new jobs and lower import bills.

Judging growth and decisions: the whole picture

Now put the three pillars to work. Two skills are tested at Higher Level: judging whether growth over a period was sustainable, and weighing up a project through cost-benefit analysis.

Was growth sustainable?

Check each pillar in turn, then conclude.

Why GDP alone is incomplete

GDP counts the value of output, not how it is shared or what it costs the environment. It ignores unpaid work, leisure, health and the depletion of natural resources, and it can rise after a disaster because of rebuilding. Two countries with the same GDP per head can have very different well-being. Other measures, such as the Gini coefficient, poverty rates and emissions data, fill the gap.

Cost-benefit analysis (CBA)

CBA lists the costs and benefits of a project, puts a euro value on them, and compares the totals. It asks: who enjoys the benefits and who bears the costs?

Take the data centre. Benefits: 300 jobs (economic and social), extra local tax revenue, possible local spending. Costs: heavy electricity use and pressure on the grid (environmental and economic), possible higher emissions, strain on local services.

Opportunity cost: the electricity capacity, land and public money used on the data centre cannot be used for something else, such as housing, other industry or renewable energy.

Limitations of CBA:

• Environmental effects are hard to value in euro, for example a lost habitat or a changed landscape.

• Costs and benefits fall on different groups, and a total can hide who loses.

• Future effects are uncertain and are often given less weight than present ones, which works against future generations.

• The result depends on the assumptions used.

A reasoned conclusion should be balanced and decisive. For example: the project may go ahead if it is conditional on renewable energy supply, investment in the grid and local hiring. Without those, the environmental and opportunity costs may outweigh the jobs.

Back to the start: the data centre brings real economic gains, but whether it is good for the county depends on how much the grid and the environment pay for it, and whether those costs can be reduced. That is the three-lens judgement.

Summary

• Sustainable development meets present needs without harming future generations' ability to meet theirs.

• The three pillars are economic (growth, jobs), social (fairness, inclusion) and environmental (emissions, water, biodiversity). They are interconnected and often involve trade-offs.

• Indicators: real GDP growth (economic); Gini coefficient and at-risk-of-poverty rate (social); greenhouse gas emissions (environmental). Percentage change $= \dfrac{\text{change}}{\text{old value}} \times 100$.

• Emissions per unit of GDP $\approx$ emissions growth $-$ GDP growth. Falling intensity is not the same as falling total emissions.

• External costs are ignored by the market. A carbon tax, regulation and subsidies can internalise them. Use the revenue to protect low-income and rural households.

• Cost-benefit analysis compares costs and benefits but struggles to value the environment, so finish with a reasoned, balanced verdict across all three pillars.

• Implications: individuals can change habits (energy use, travel), firms can cut waste and invest in efficiency, and government can use taxes, regulation and spending. Indicators are linked: growth can raise emissions or inequality, so check all three together.

Key terms: sustainable development, economic / social / environmental sustainability, indicator, Gini coefficient, at-risk-of-poverty rate, external cost, internalising an externality, carbon tax, opportunity cost, cost-benefit analysis.