akar.earthProject scenario: Definition
What is a project scenario in carbon accounting? How project emissions and removals are monitored and compared with the baseline to calculate credits.
A project scenario is the actual situation in a carbon project area once the project activities are implemented, including all carbon stock changes and greenhouse gas emissions they cause. It is compared with the baseline scenario to calculate net emission reductions or removals.
Why it matters
Credits come from the gap between baseline and project. A well-measured project scenario gives that gap its credibility. Unlike the baseline, which is a counterfactual, the project scenario can be observed directly, so verifiers expect strong field and remote sensing evidence for it.
How it is quantified
The project scenario has two parts:
- Carbon stock changes: growth of trees in ARR, or the forest stock maintained in REDD+, across the carbon pools included.
- Project emissions: greenhouse gases released by the activities themselves, such as burning during site preparation, nitrogen fertiliser, vehicle fuel, or clearing existing shrubs before planting.
Net benefit = (project removals − project emissions) − baseline net removals − leakage, then minus uncertainty and buffer deductions.
The project design document gives an ex-ante estimate. Each monitoring report then presents measured results for the monitoring period, which a VVB verifies.
Indonesia angle
For Indonesian ARR and agroforestry projects, project emissions are often small but not zero: clearing alang-alang grass, using fertiliser in nurseries, and transporting seedlings over long distances to outer islands. In REDD+ and peat projects, the project scenario must show that patrolling, fire prevention and canal blocking actually reduced loss compared with the baseline. Dense, repeatable plot data and satellite monitoring are the backbone of that evidence.
Common mistakes
- Reporting gross tree growth without subtracting project emissions.
- Ignoring biomass removed when existing vegetation is cleared before planting.
- Measuring the project scenario with different plots or methods than were used to design the baseline.
- Counting growth in areas that fell outside the registered project boundary.
Related terms
See baseline scenario, leakage and ex-post, or explore the carbon standards hub.
Frequently asked questions
What is included in project emissions?
Any greenhouse gas emissions caused by project activities inside the project boundary, such as fertiliser use, fossil fuel for machinery, burning during site preparation, or removal of existing vegetation.
Is the project scenario estimated or measured?
It is estimated ex-ante in the project design document, then measured ex-post through monitoring before each verification.