Environmental Economics Vocabulary in English

Carbon pricing is a policy mechanism that puts a direct price on greenhouse gas emissions to create financial incentives for reducing them. The two main forms are carbon taxes (a fixed price per tonne of CO2 equivalent) and emissions trading schemes (ETS), also called cap-and-trade (where a cap on total emissions is set and companies can buy and sell permits). Carbon pricing is advocated by most economists as cost-effective because it allows flexibility in how and where reductions are made. Critics argue it can disproportionately affect lower-income households without complementary redistribution.

Natural capital refers to the world's stock of natural resources — soils, forests, water, minerals, oceans, and biodiversity — that provide flows of valuable goods and services to humans. The concept extends economic capital accounting to include the natural environment as a productive asset. Natural capital provides ecosystem services such as clean water, food production, climate regulation, pollination, and flood protection. Unlike manufactured capital, natural capital can be permanently depleted. Valuing natural capital in economic terms aims to make environmental costs visible in decision-making.

Weak sustainability holds that natural capital and manufactured capital are substitutable — a society can deplete natural resources as long as it creates enough manufactured or human capital to compensate. Strong sustainability holds that certain forms of natural capital are critical and cannot be substituted, such as clean air, functioning ecosystems, and stable climate. This debate underpins fundamental disagreements about how much environmental protection is economically justified and whether economic growth can continue indefinitely on a finite planet.

Ecosystem services are the benefits that ecosystems provide to human beings, grouped into four categories: provisioning services (food, water, timber), regulating services (climate regulation, flood control, pollination), cultural services (recreation, aesthetic value), and supporting services (soil formation, nutrient cycling). The Millennium Ecosystem Assessment framework attempts to make the economic value of nature visible and to integrate it into decision-making by governments, businesses, and communities.

A Pigouvian tax (named after economist Arthur Pigou) is a tax levied on a market activity that generates negative externalities, set at a level equal to the marginal external cost. The purpose is to internalise the external cost into the price so the market reaches a socially optimal output level. A carbon tax is the most prominent example — it adds the cost of CO2 emissions to the price of fossil fuels, incentivising producers and consumers to switch to lower-carbon alternatives. Accurately measuring externalities for tax-setting is difficult in practice.

The tragedy of the commons, introduced by Garrett Hardin, describes the depletion of a shared resource through individual self-interested use that exceeds the resource's renewal capacity. When a resource is freely accessible, each individual has an incentive to maximise their own use before others do, even though collective overuse destroys it. Classic examples include overfishing and overgrazing. Solutions include privatisation, government regulation, and community governance — the last of which was studied by Nobel laureate Elinor Ostrom.

A circular economy is an economic model designed to eliminate waste and keep materials in use for as long as possible, in contrast to the traditional linear ‘take-make-dispose’ model. It involves designing products for longevity, repairability, and recyclability, and recovering materials at the end of their useful life. The circular economy concept draws on industrial ecology, biomimicry, and cradle-to-cradle design principles. It is increasingly adopted as a framework by governments and businesses in sustainability policy.

Cost-benefit analysis (CBA) compares the total expected costs and benefits of a policy or project, usually in monetary terms, to determine whether it is worthwhile. In environmental economics, CBA is used to evaluate environmental regulations, infrastructure projects, and conservation programmes. Challenges include valuing non-market goods (clean air, biodiversity, future generations' welfare) and choosing appropriate discount rates. Critics argue that CBA tends to undervalue environmental goods and overvalue short-term economic returns.

Organise terms by concept: market failure (externality, public goods, tragedy of the commons), policy instruments (carbon tax, ETS, Pigouvian tax, subsidy reform), valuation (natural capital, ecosystem services, contingent valuation), and frameworks (circular economy, strong/weak sustainability, doughnut economics). Reading the Stern Review on the Economics of Climate Change, IPCC reports, and the Economist's environmental coverage provides excellent authentic exposure. Following economists such as Nicholas Stern, Kate Raworth, and Partha Dasgupta on public platforms also builds vocabulary in engaging contexts.