Environmental Studies – Skill Enhancement Study Notes
(For B.A. Economics – Competitive Exam Preparation – IIT‑JEE / National‑Level)
Note – These notes are written to help you master the core ideas, derivations, and quantitative tools that frequently appear in competitive exams.
All formulae are given in a compact form; you can always expand them for specific problem‑solving.
1. Introduction
| Concept | Definition | Relevance in Economics |
|---|---|---|
| Environmental Economics | Branch of economics that studies the interactions between the economy and the environment, focusing on externalities, public goods, and resource allocation. | Central to policy design, cost‑benefit analysis, and sustainability planning. |
| Externality | A cost or benefit that affects a third party who is not part of the transaction. | Leads to market failure → need for government intervention. |
| Public Good | A good that is non‑rival and non‑excludable (e.g., clean air). | Hard to finance through markets; often subsidized or protected by law. |
| Common‑Pool Resource | A resource that is non‑rival but excludable (e.g., fisheries). | Prone to over‑exploitation (“tragedy of the commons”). |
2. Economic Analysis of Environmental Problems
2.1 Cost‑Benefit Analysis (CBA)
Net Present Value (NPV)
[
\text{NPV} = \sum_{t=0}^{T}\frac{B_t - C_t}{(1+r)^t}
]
- (B_t) – benefits in year (t)
- (C_t) – costs in year (t)
- (r) – discount rate (reflects time‑value of money)
- (T) – project lifetime
Decision Rule
- If NPV > 0, the project is economically viable.
- If NPV < 0, reject the project.
Exam Tip: In JEE‑style questions, you’ll often have to compute a discounted benefit or cost and then decide on feasibility.
2.2 Marginal Abatement Cost Curve (MACC)
- Definition: A curve that shows the marginal cost of reducing an additional unit of pollution (e.g., one tonne of CO₂).
- Formula:
[ \text{MAC} = \frac{dC}{dE} ] where (C) is total abatement cost and (E) is emission level.
Optimal Emission Level
- Set MAC = Social Cost of Emission (SCE)
- Mathematically: ( \frac{dC}{dE}\bigg|_{E^*} = \text{SCE})
Derivation Example
Suppose total abatement cost (C(E) = 5E^2 + 20E).
[ \text{MAC} = \frac{dC}{dE} = 10E + 20 ] If SCE = ₹120 per tonne, solve (10E + 20 = 120 \Rightarrow E^* = 10) tonnes.
2.3 Coase Theorem
| Condition | Explanation |
|---|---|
| Zero transaction costs | Parties can negotiate freely. |
| Clearly defined property rights | Parties know exactly what they |