The Core Principles

Externalities and Market Failure

A fundamental concept is ‘externalities’—costs or benefits not reflected in the price of a good. For example, pollution from a factory imposes costs on public health and ecosystems, but the factory doesn't bear these full costs when it decides to produce.

This leads to ‘market failure,’ where the market inefficiently allocates resources because prices don’t accurately represent true social costs. The classic example is a pig farm polluting a river – the farmer benefits, but society loses.

External Cost = Social Cost - Private Cost

Cost-Benefit Analysis

Environmental policy decisions often rely on cost-benefit analysis. This involves quantifying the monetary value of environmental impacts (e.g., reduced air pollution, habitat preservation) and comparing them to the costs of implementing a particular solution.

However, assigning monetary values to intangible things like biodiversity or ecosystem services is complex and frequently debated.

Net Benefit = Total Benefits - Total Costs

Instruments of Environmental Policy

Governments use various tools to address market failures. These include ‘Pigouvian taxes’ – taxes on pollution that internalize the external cost, and subsidies for clean technologies.

Regulations (e.g., emission standards) also play a role, but can be less economically efficient than using market-based instruments.

Tax Revenue = Marginal External Cost per Unit

Sustainable Development

The concept of ‘sustainable development’ – meeting the needs of the present without compromising the ability of future generations to meet their own needs – is central to environmental economics.

This requires integrating economic growth with ecological limits and social equity. Measuring true progress goes beyond simply GDP and includes indicators like the Genuine Progress Indicator (GPI).

Frequently asked questions

Try it live

Everything above runs in your browser — open Solow Growth Model and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.