Example
A business might compare annual emissions with a selected base-year inventory.
The catch
Major structural changes may require recalculation under the relevant standard.
In more depth
Base year, explained.
A base year is the anchor for every reduction a company announces, so a percentage cut means little until you know which year it starts from. Choosing an unusually high year flatters later progress. A year when factories ran flat out, or one before a big efficiency upgrade, makes ordinary results look dramatic. A pandemic year with empty offices does the opposite, since the rebound afterwards looks like failure.
The GHG Protocol asks companies to choose a year with reliable, verifiable data and to recalculate it when methods improve or errors come to light, so comparisons stay like for like. Check that the base-year emissions inventory covers the same gases and scopes as the current one. A target set against a narrower boundary can show progress that exists only on paper.