Carbon intensity

“Efficiency can improve while total emissions continue to rise. ”

Carbon intensity divides emissions by something else: tonnes of product, megawatt-hours, passenger-kilometres, floor area or revenue. The metric helps compare performance across scale and can reveal whether an activity is becoming less emissions-intensive. The denominator determines the story. Emissions per tonne can fall because technology improved, product mix changed or utilisation increased.

Emissions per unit of revenue can fall because prices rose, inflation changed or high-emitting activities were sold. Intensity is therefore a ratio, not a self-interpreting measure of climate progress. The central risk is the rebound between intensity and volume. A company can reduce emissions per unit by 20 percent while increasing production by 40 percent, causing absolute emissions to rise.

That may represent genuine efficiency, but it is not equivalent to decarbonisation at the rate required by a carbon budget. Intensity metrics are especially useful in heterogeneous sectors where output changes or products differ. Sector pathways often use physical intensity because it links technology to service delivered.

Financial intensity can support portfolio screening, but changes in valuation can produce apparent improvements without changes in the real economy. Organisations should therefore report intensity and absolute emissions together. They should also preserve denominator consistency and explain structural shifts.

A decline caused by outsourcing, product mix or currency movements should not be presented as operational abatement. Used carefully, carbon intensity can locate efficiency opportunities and compare similar activities.

Used alone, it can make growth look climate-compatible even when cumulative emissions continue to increase.

Practical application

Define the numerator, denominator, boundary and period. Choose a denominator linked to the decision being made. Recalculate historical data after material structural changes, and pair intensity trends with absolute emissions and production volumes.

Why it matters

Intensity metrics reveal efficiency but can obscure scale. Climate outcomes depend on atmospheric totals, not ratios alone.

Common misconception

Lower carbon intensity always means lower climate impact. Total impact can rise if activity grows faster than intensity falls.

Connections

Absolute Target and Intensity Target distinguish target forms. Carbon Budget explains why cumulative totals matter. Rebound Effect shows how efficiency gains can be offset by growth.

A question worth asking

If your intensity improved, what happened to absolute emissions and total output over the same period?

Selected references

GHG Protocol, Corporate Standard. Science Based Targets initiative, target-setting methods. IPCC, mitigation pathways and emissions-intensity indicators.

How it is used

In professional practice, “Carbon intensity” helps governments, companies, investors and technical teams describe or assess greenhouse-gas emissions expressed per unit of activity, output, revenue, energy, product or another defined denominator. It is commonly encountered in climate strategies, transition plans, emissions inventories, scenarios and investment decisions.

A credible application identifies the relevant methodology, emissions boundary, baseline, timeframe and underlying data.