Environmental Economics

Environmental economics is a sub-field of economics that is concerned with environmental issues. Quoting from the National Bureau of Economic Research Environmental Economics program:

[...] Environmental Economics [...] undertakes theoretical or empirical studies of the economic effects of national or local environmental policies around the world [...]. Particular issues include the costs and benefits of alternative environmental policies to deal with air pollution, water quality, toxic substances, solid waste, and global warming.

Environmental economics is distinguished from ecological economics in that ecological economics emphasizes the economy as a subsystem of the ecosystem with its focus upon preserving natural capital. One survey of German economists found that ecological and environmental economics are different schools of economic thought, with ecological economists emphasizing "strong" sustainability and rejecting the proposition that natural capital can be substituted by human-made capital.

Central to environmental economics is the concept of market failure. Market failure means that markets fail to allocate resources efficiently. As stated by Hanley, Shogren, and White (2007) in their textbook Environmental Economics: "A market failure occurs when the market does not allocate scarce resources to generate the greatest social welfare. A wedge exists between what a private person does given market prices and what society might want him or her to do to protect the environment. Such a wedge implies wastefulness or economic inefficiency; resources can be reallocated to make at least one person better off without making anyone else worse off." Common forms of market failure include externalities, non-excludability and non-rivalry.

An externality exists when a person makes a choice that affects other people in a way that is not accounted for in the market price. An externality can be positive or negative, but is usually associated with negative externalities in environmental economics. For instance, water seepage in residential buildings happen in upper floor affect the lower floor. Or a firm emitting pollution will typically not take into account the costs that its pollution imposes on others. As a result, pollution may occur in excess of the 'socially efficient' level, which is the level that would exist if the market was required to account for the pollution. A classic definition influenced by Kenneth Arrow and James Meade is provided by Heller and Starrett (1976), who define an externality as “a situation in which the private economy lacks sufficient incentives to create a potential market in some good and the nonexistence of this market results in losses of Pareto efficiency.” In economic terminology, externalities are examples of market failures, in which the unfettered market does not lead to an efficient outcome.

...
Wikipedia