Environment as a Public Good | UGC NET Economics – Notes

Introduction

The environment, encompassing air, water, forests, biodiversity, and climatic stability, occupies a distinctive position in economic theory because many of its components do not conform to the assumptions of conventional private goods traded in competitive markets. Environmental economics analyses how the characteristics of environmental resources — particularly non-excludability and non-rivalry — lead to systematic market failure, and examines the range of policy instruments available to correct this failure. The foundational insight, traceable to A.C. Pigou’s The Economics of Welfare (1920) and later formalised by Paul Samuelson in his 1954 paper “The Pure Theory of Public Expenditure,” is that goods with public-good characteristics will be under-provided by private markets relative to the socially optimal level, necessitating collective or governmental action.

Defining Public Goods

A pure public good is defined by two properties: non-excludability, meaning it is technically impossible or prohibitively costly to prevent any individual from consuming the good once it is provided, and non-rivalry (or non-rivalrous consumption), meaning one individual’s consumption of the good does not diminish its availability to others. Formally, if (X) is the total quantity of a public good provided and (x_i) is the quantity consumed by individual (i), then for a pure public good:

$$ X = x_1 = x_2 = \dots = x_n $$

in contrast to a private good, where \(X = \sum_{i=1}^{n} x_i\). Goods possessing both properties fully are termed pure public goods (classic examples include national defence and clean atmospheric air), while goods possessing only one property are termed impure public goods. A good that is non-excludable but rivalrous is termed a common pool resource or common property resource (e.g., ocean fisheries, groundwater, grazing land), while a good that is excludable but non-rivalrous is termed a club good (e.g., cable television, toll roads below congestion). This fourfold classification, often presented as a 2×2 matrix of excludability and rivalry, is central to environmental economics because most environmental resources fall into the public-good or common-pool categories rather than being pure private goods.