Which one of the following statements best describes the term ‘Social Cost of Carbon’? It is a measure, in monetary value, of the

The correct answer is A. Social Cost of Carbon (SCC) is an economist's estimate, in money terms, of the total damage caused by emitting one extra tonne of CO2 in a given year. That damage is spread over decades and centuries: crop losses, health costs, coastal flooding, heat-related deaths and so on. Analysts discount these future costs to arrive at a present value.

Why the others are wrong:

• B describes the fossil fuel requirement of an economy or its energy intensity. It is a physical or energy accounting idea, not a monetary damage estimate.
• C refers to adaptation by climate migrants. That is a social and humanitarian concept and has nothing to do with carbon pricing.
• D describes an individual's carbon footprint, which is a measure of emissions, not a monetary valuation of damage.

Core concept: SCC is the basis for carbon pricing and cost-benefit analysis of climate policy. For Mains, connect it to the polluter pays principle, carbon taxes and the debate on how much the world should spend today to avoid future climate damage.

Trap: aspirants often confuse SCC with the market price of carbon credits or a carbon tax. SCC is a damage estimate, not what a market actually charges.