Mitigation Hierarchy — Definition and GHG Accounting Context
Faced with a carbon footprint, a company has a choice of where to start — and the order it chooses is the difference between real climate action and a marketing claim. Buying offsets is easy; avoiding the emissions in the first place is not.
The mitigation hierarchy fixes the order: avoid and reduce first, neutralise only what genuinely remains, and treat offsetting as a last resort — never a shortcut.
The mitigation hierarchy is the prioritised order of climate actions a company should follow: first avoid and reduce its own emissions as far as possible, then neutralise the small residual with permanent removals, and only use compensation beyond its value chain as an additional step — not a substitute for reduction.
What the mitigation hierarchy is
The mitigation hierarchy is a prioritised sequence for tackling greenhouse-gas emissions: work through the steps in order, exhausting each before relying on the next, so that reducing emissions at the source always takes precedence over compensating for them elsewhere.
Its purpose is to prevent the easiest option — paying for offsets — from displacing the necessary one — cutting your own emissions. The hierarchy makes reduction the default and offsetting the exception, applied only to what genuinely cannot be abated. It underpins credible net-zero frameworks and is the principle regulators and standard-setters invoke when they judge whether a climate claim is real or greenwashing.
This page defines the hierarchy and its order; the individual measures within it — the specific reductions — are covered by abatement, and the calculators this entry links to model the resulting pathway.
The order of action
The corporate climate mitigation hierarchy runs from most to least preferable. The first three steps reduce a company’s own footprint; only then do removals and compensation enter.
| Step | Action | Example |
|---|---|---|
| 1. Avoid | Prevent the emissions arising at all | Cut unnecessary travel; design out emissions-intensive inputs |
| 2. Reduce | Minimise the emissions you cannot avoid | Energy efficiency, electrification |
| 3. Substitute | Switch to lower-carbon inputs and energy | Renewable power, green hydrogen, low-carbon materials |
| 4. Neutralise | Remove an equal amount of the residual from the atmosphere | Permanent carbon removals for hard-to-abate emissions |
| 5. Compensate | Support additional climate action beyond your value chain | Financing mitigation elsewhere — as a contribution, not a target |
Applied to a footprint, the hierarchy drives emissions down step by step until only a small residual remains to be neutralised:
Illustrative: emissions remaining after each step of the hierarchy. Removals apply only to the 8% residual — not the whole footprint.
Why “reduce before offset” matters
The order is not arbitrary — it reflects that not all tonnes are equal. A tonne of emissions avoided at the source is certain and permanent; a tonne offset elsewhere depends on the quality, additionality, and durability of the credit, and does nothing to change the company’s own trajectory. Reversing the order — buying cheap offsets instead of making available reductions — leaves the real footprint untouched behind a neutral-sounding claim.
The hierarchy is what makes a net-zero claim credible. Deep reduction first, removals only for the genuine residual, compensation as an optional extra — in that order. Inverting it, so offsets substitute for reduction, is the single most common form of climate greenwashing.
Neutralisation vs compensation
The two steps that follow reduction are often conflated, but standards treat them very differently:
- Neutralisation addresses your own residual emissions by removing an equivalent amount of CO₂ from the atmosphere — permanent removals, matched to the residual, are what count toward net zero.
- Compensation (beyond-value-chain mitigation) funds climate action outside your footprint — a valuable contribution, but separate from your target and not a substitute for reducing or neutralising your own emissions.
The distinction also drives credit quality: neutralising a residual requires durable removals, not the cheap avoidance credits that the removal-versus-avoidance debate warns against. A carbon offset used as compensation is legitimate; the same credit passed off as neutralising your residual, when it is an avoidance credit, is not.
Worked micro-example
A company with a 100,000 tCO₂e footprint works down the hierarchy toward net zero.
| Step | Emissions remaining |
|---|---|
| Gross footprint | 100,000 tCO₂e |
| 1–2. Avoid & reduce | 20,000 tCO₂e |
| 3. Substitute | 8,000 tCO₂e (residual) |
| 4. Neutralise residual with removals | 0 net = net zero |
The company reaches net zero by removing 8,000 tCO₂e — the residual — not 100,000. Contrast the shortcut: a company that skipped steps 1–3 and simply bought 100,000 tCO₂e of cheap avoidance offsets could announce itself “carbon neutral” while still emitting the full 100,000 tCO₂e. Same claim, opposite reality — and exactly the inversion the hierarchy exists to prevent.
Common mistakes
- Jumping straight to offsets. Offsetting is the last step, applied to the residual — not a substitute for the avoid, reduce, and substitute steps that come first.
- Treating all tonnes as equal. A tonne avoided at the source is certain; a tonne offset depends on credit quality and does not change your own footprint.
- Confusing neutralisation with compensation. Removals matched to your residual count toward net zero; funding action beyond your value chain is an additional contribution, not a target substitute.
- Neutralising with avoidance credits. A residual is neutralised with durable removals; avoidance credits are compensation at best, not neutralisation.
- Removing the whole footprint instead of the residual. Removals scale to the small remainder after deep reduction, not the gross footprint — that is what makes them affordable and credible.
Model a hierarchy-aligned pathway — reduce first, neutralise the residual.
Frequently asked questions
The mitigation hierarchy is the prioritised order of climate actions a company should follow: avoid emissions, then reduce and substitute what remains, then neutralise the small residual with permanent removals, and only use compensation beyond the value chain as an additional step. It puts reduction first and treats offsetting as a last resort, not a shortcut.
Because not all tonnes are equal. A tonne avoided at the source is certain and permanent, while a tonne offset elsewhere depends on the credit’s quality and does nothing to change the company’s own emissions. Following the order ensures real reductions happen first; inverting it — offsetting instead of reducing — is the most common form of climate greenwashing.
Neutralisation removes an amount of CO₂ from the atmosphere equal to your own residual emissions, using permanent removals — this is what counts toward net zero. Compensation (beyond-value-chain mitigation) funds climate action outside your footprint as an additional contribution. Only neutralisation with removals cancels your residual; compensation does not.
Yes, but in its proper place. Permanent removals neutralise the residual that remains after deep reduction, and compensation beyond the value chain is encouraged as an extra contribution. What the hierarchy rules out is using offsets — especially cheap avoidance credits — in place of reducing your own emissions.
Net zero is reached by following the hierarchy: reduce emissions deeply (around 90%), then neutralise the small residual with permanent removals. The hierarchy is what makes a net-zero claim credible — it ensures the bulk of the work is real reduction, with removals applied only to the genuine remainder rather than the whole footprint.