How long should our emissions target period be: one year or several?
A multi-year commitment period reduces the risk that one unusual year decides whether you meet the target, because the whole period counts. A single-year period judges only the commitment year. Many companies use one year; the GHG Protocol notes both are allowed.
What the commitment period is
It is the span during which your emissions are measured against the target, and it ends at the target completion date. Do not confuse it with the completion date itself, which sets how far ahead the target looks.
The two options
- One year: the target is met if emissions in the commitment year are at or below the goal.
- Several years: the total, or the average, over the period must be at or below the goal.
Why longer periods help
The standard says periods longer than one year mitigate the risk of unpredictable events in one particular year affecting performance. A furnace failure or a lost customer in the final year would otherwise decide the result.
Rolling base year users
If your target uses a rolling base year, the commitment period applies throughout: performance is measured against the target every year until the completion date.
Example with made-up numbers: base year 500 t, target 10% lower
- Goal: 500 x 0.90 = 450 t a year.
- Emissions in 2028, 2029 and 2030: 440 t, 430 t and 475 t (a breakdown year in 2030).
- Single-year period (2030 only): 475 t is above 450 t, so the target is missed.
- Three-year period (2028 to 2030): the total must be at or below 450 x 3 = 1,350 t. Actual: 440 + 430 + 475 = 1,345 t. The target is met.
The standard's own illustration uses the same logic over five years.
What Senseible does here
Senseible keeps monthly energy and emission records, so a year that looks off can be traced to its bills before it is reported against the target.
Sources: GHG Protocol, Corporate Accounting and Reporting Standard, chapter 11 (Setting a GHG target)
Last reviewed 2026-11-03.