UPSC Prelims 2021 Q29: UNEP Common Carbon Metric — Explained
The 'Common Carbon Metric', supported by UNEP, has been developed for
- assessing the carbon footprint of building operations around the world
- enabling commercial farming entities around the world to enter carbon emission trading
- enabling governments to assess the overall carbon footprint caused by their countries
- assessing the overall carbon footprint caused by the use of fossil fuels by the world in a unit time
Answer: (a) assessing the carbon footprint of building operations around the world
Statement-wise explanation
- a: correct — The Common Carbon Metric (CCM) was developed by UNEP's Sustainable Buildings and Climate Initiative (UNEP-SBCI). Its full title states its purpose: a common carbon metric for measuring energy use and reporting greenhouse gas emissions from building operations. It reports energy as kWh per square metre per year and emissions as kgCO2e per square metre per year (or per occupant per year), so buildings anywhere in the world can be compared on one basis.
- b: incorrect — The CCM has nothing to do with agriculture or with emission trading. It is a measurement and reporting protocol for the energy use and emissions of operational buildings. It does not create credits or give any entity entry into a carbon market.
- c: incorrect — Countries measure their overall emissions through national greenhouse gas inventories reported to the UNFCCC, and those inventories follow IPCC methodological guidelines. The CCM covers one sector, buildings, and works at the level of a single building or a building stock. It is not a national accounting tool.
- d: incorrect — No UNEP metric called the Common Carbon Metric measures global fossil-fuel emissions per unit of time. The CCM's unit is per square metre (or per occupant) per year of building operation. Its denominator is floor area, not 'the world'.
How to eliminate
This question can only be solved by knowing the fact. There are no absolute words to exploit, and all four options sound like plausible carbon-accounting tools. Two weak clues help a little. First, the word 'Common' points to a shared yardstick that lets similar units (buildings, firms, products) be compared with each other. Option (c) and option (d) describe whole-country or whole-world totals, and those already have established systems: UNFCCC national inventories built on IPCC guidelines. Second, option (b) mixes two separate ideas, measurement and trading, and a 'metric' only measures. These clues may narrow the choice to option (a) or option (b), but they do not settle it. The fact to remember is: Common Carbon Metric = UNEP-SBCI = energy use and emissions of buildings in operation, in kWh/m²/year and kgCO2e/m²/year.
Know more
Why buildings get their own carbon yardstick
UNEP's Common Carbon Metric document puts the building sector at about 40% of global energy use and about one-third of global greenhouse gas emissions. Without a shared unit, buildings in different countries cannot be compared, and claims of efficiency cannot be checked.
The Common Carbon Metric (CCM) was developed by UNEP's Sustainable Buildings and Climate Initiative (SBCI) and unveiled in 2009, around COP15 in Copenhagen. Its key features:
| Feature | Common Carbon Metric |
|---|---|
| Developed by | UNEP-SBCI |
| What it measures | Energy use and GHG emissions of buildings |
| Phase covered | Operational phase only (heating, cooling, lighting, appliances), not construction or embodied carbon |
| Units | kWh/m²/year; kgCO2e/m²/year (or per occupant/year) |
| Approaches | Top-down (a whole building stock); bottom-up (a single building) |
| Later use | Proposed to ISO as a basis for international building standards |
Do not confuse it with these:
| Tool | Level | Purpose |
|---|---|---|
| National GHG inventory (IPCC guidelines) | Country | Reporting to the UNFCCC |
| Carbon footprint | Product, person or firm | Life-cycle emissions |
| Energy Conservation Building Code (ECBC, 2007; updated 2017) | Indian commercial buildings | Minimum energy-efficiency design standards (BEE) |
| Eco Niwas Samhita (2018; 2021) | Indian residential buildings | Residential energy code (BEE) |
India link: The Bureau of Energy Efficiency (BEE) regulates building energy through the ECBC for commercial buildings and Eco Niwas Samhita for homes. Eco Niwas Samhita Part I (the building envelope) came out on National Energy Conservation Day 2018, and Eco Niwas Samhita 2021 followed in July 2021. A metric like the CCM measures how a building actually performs once in use, while these codes set the design standard it must meet.
NCERT Concepts to Revise
- Intergovernmental Panel on Climate Change: The IPCC, set up by WMO and UNEP, writes the guidelines countries use for national emission inventories, a different scale from a buildings metric.