The concept of 'carbon credit' originated from

The answer is B) Kyoto Protocol. Adopted in 1997 and in force from 2005, it set legally binding emission-reduction targets for Annex I (developed) countries. To make those targets affordable, it created flexible mechanisms: the Clean Development Mechanism, Joint Implementation and International Emissions Trading. A carbon credit, typically one tonne of CO2-equivalent reduced or removed, is the unit that these mechanisms trade. That is why the concept is traced to Kyoto.

• A) Earth Summit, 1992: It produced the UNFCCC, the framework convention. It set no binding targets and created no tradable credits.
• C) Montreal Protocol, 1987: It phases out ozone-depleting substances such as CFCs. It is an ozone regime, not a carbon-trading one.
• D) G-8 Summit, Heiligendam, 2007: It was a political summit on growth and climate. It did not originate any market mechanism.

Mains angle: India's own carbon market framework, under the Energy Conservation (Amendment) Act, 2022, builds on the same logic. It is a useful example for questions on market-based climate instruments and the CBDR principle.

Trap: Aspirants pick Rio because it is the 'birth' of climate diplomacy. Rio gave us the framework, but the credit mechanism came with Kyoto.