akar.earthEmission reduction: Definition
What is an emission reduction in carbon markets? How reductions are calculated against a baseline, how they become credits, and how Indonesia counts them.
An emission reduction is a measurable decrease in greenhouse gas emissions compared with what would have happened otherwise, expressed in tonnes of CO2 equivalent. In carbon markets, it is the difference between baseline emissions and actual project emissions, after leakage.
Why it matters
Emission reductions are the core unit of most climate policy and much of the carbon market. Many credit types, from REDD+ to cookstoves, are emission reduction credits. The term is also used in jurisdictional programmes such as the World Bank’s FCPF Emission Reductions Payment Agreements. Clarity matters, because buyers increasingly distinguish emission reductions (avoided emissions) from removals.
How it is calculated
Emission reductions = baseline emissions − project emissions − leakage
For forest projects:
- Activity data: area of forest lost or degraded, from satellite imagery.
- Emission factors: carbon lost per hectare, from field plots and allometry, converted to tCO2e.
- Baseline: expected loss without the project, set by the baseline scenario method.
Deductions for uncertainty and buffer contributions apply before issuance. Results are reported per monitoring period and per vintage.
Indonesia angle
Indonesia’s carbon trading rules use the term SPE-GRK (Sertifikat Pengurangan Emisi Gas Rumah Kaca), meaning a greenhouse gas emission reduction certificate. SPE-GRK units are the offset units traded on IDXCarbon, recorded in SRUK. See our page on SPE-GRK. In practice the domestic certificate can cover both reductions and removals, so check how a unit was generated. Indonesia also reports national emission reductions against its NDC and the FOLU Net Sink 2030 target.
Common mistakes
- Using “emission reduction” for removals in contracts, which confuses buyers’ claims.
- Quoting gross reductions without leakage and buffer deductions.
- Comparing reductions measured against different baselines as if equivalent.
- Forgetting that domestic and international units may describe the same reduction, which must only be claimed once.
Related terms
See avoidance credit, tCO2e and baseline scenario, or browse the forest carbon hub.
Frequently asked questions
Is an emission reduction the same as a carbon credit?
No. An emission reduction is the measured climate result. It becomes a credit only after verification and issuance by a programme, and after deductions.
How are forest emission reductions measured?
By comparing monitored forest loss and its carbon content with a baseline of expected loss, using satellite data, field plots and emission factors.