Counterfactual
A reasoned account of what would have happened under different conditions.
Example
Evaluating project finance asks whether the activity would proceed without that support.
The catch
The alternative cannot be directly observed and must be justified.
In more depth
Counterfactual, explained.
Every avoided tonne in climate accounting is a difference between what happened and a counterfactual, so the counterfactual carries most of the risk. Additionality, the baseline scenario and avoided emissions all rest on one. Because nobody can observe the world that did not happen, analysts approximate it with historical trends, models or comparison sites.
Comparison sites often give the strongest evidence. Newer forest methods compare a protected area with similar unprotected forest tracked by satellite, and update the estimate as events unfold. A counterfactual fixed at the start of a project and never revisited deserves more doubt, especially when it predicts a future far worse than the recent past.