What is business carbon intensity and how do you calculate it?

Unlike an absolute carbon footprint, which shows the total greenhouse gas emissions generated during a reporting period, carbon intensity provides context. It can help businesses understand whether emissions are becoming more or less intensive as the organisation grows, contracts or changes its level of activity.

Used alongside an absolute carbon footprint, it can provide a more useful picture of carbon performance over time.

Key takeaways

• Carbon intensity expresses emissions relative to a relevant business metric.
• The most useful denominator depends on the organisation and should be applied consistently.
• Carbon intensity should complement, rather than replace, measurement of your total carbon footprint.

What does carbon intensity mean for a business?

Carbon intensity is a way of relating greenhouse gas emissions to business activity.

A company could reduce its total emissions simply because it produced fewer goods or generated less revenue. Equally, its absolute emissions could increase while the business becomes more carbon efficient because its output has grown at a faster rate.

An intensity metric helps put those changes into context.

For example, a manufacturer might monitor emissions per unit produced, while another organisation could use emissions relative to turnover. The appropriate measure should reflect how the business operates and what it wants to understand.

How do you calculate carbon intensity?

The basic calculation compares greenhouse gas emissions with a chosen measure of business activity:

Carbon intensity = greenhouse gas emissions ÷ business activity

For example, imagine a manufacturer reports 500 tonnes of carbon dioxide equivalent (tCO2e) during the year and produces 100,000 units.

Its carbon intensity would be:

500 ÷ 100,000 = 0.005 tCO2e per unit

This could also be expressed as 5 kgCO2e per unit.

The important point is that the emissions figure and business activity data relate to the same reporting period and are measured consistently.

Which carbon intensity metric should you use?

There is no single denominator that is appropriate for every business.

Possible measures include:

• revenue or turnover
• number of products manufactured
• tonnes of material produced
• floor area
• another relevant measure of business activity

A manufacturing business may gain more useful insight from emissions per unit of production than emissions per pound of turnover. A service-based organisation may need a different measure entirely.

The metric should be meaningful to the organisation and consistent enough to allow useful comparisons over time.

What emissions should you include?

Before calculating carbon intensity, you need a reliable carbon footprint.

Green Economy explains business carbon footprints through Scope 1, Scope 2 and Scope 3 emissions. Scope 1 covers emissions from sources the organisation owns or controls, Scope 2 covers emissions associated with purchased energy, and Scope 3 covers wider indirect emissions across the value chain.

Businesses should clearly define which emissions are included in their intensity calculation. Changing the organisational boundary or included emissions without accounting for that change can make comparisons between reporting periods misleading.

Why calculate carbon intensity as well as total emissions?

Absolute emissions tell you the overall scale of your carbon footprint. Carbon intensity helps you understand those emissions in relation to business performance.

Imagine production rises substantially from one year to the next. Total emissions may also increase, but emissions per unit produced could fall.

Conversely, absolute emissions could decrease while carbon intensity worsens if output falls even faster.

Looking at both measures helps businesses distinguish genuine improvements in carbon efficiency from changes caused primarily by business activity.

How can you compare carbon intensity over time?

Consistency is essential.

Businesses should use the same calculation method, emissions boundary and business activity metric wherever possible. They should also retain clear records of the underlying data and assumptions.

Green Economy recommends using a defined 12-month reporting period when calculating a business carbon footprint and applying the latest appropriate emissions factors to activity data.

If the methodology or scope changes significantly, this should be documented so decision-makers understand why the figures may not be directly comparable.

Can carbon intensity show whether your business is decarbonising?

Carbon intensity can provide useful evidence of improving carbon efficiency, but it should not be considered in isolation.

A falling intensity figure means emissions are decreasing relative to the chosen business metric. It does not necessarily mean total emissions are falling.

For example, a rapidly growing business could reduce emissions per product while its overall footprint continues to increase.

For that reason, businesses should monitor carbon intensity alongside absolute Scope 1, Scope 2 and relevant Scope 3 emissions. This provides a more complete view of progress.

How can carbon intensity help identify improvements?

Carbon measurement is most valuable when businesses use the information to make decisions.

Green Economy advises businesses to use their carbon footprint to identify where the most significant emissions occur and prioritise suitable reduction measures. Its guidance notes that collecting carbon data can help organisations identify improvements in how they use energy, fuel and other resources.

Tracking an appropriate carbon intensity metric can add another layer to this analysis by showing whether emissions efficiency is improving as business activity changes.

Why reliable carbon data matters

A carbon intensity calculation is only as reliable as the information behind it.

Businesses need accurate activity data for their carbon footprint as well as reliable data for the denominator used in the intensity calculation.

Green Economy highlights electricity bills, fuel use, mileage and other operational records as potential sources of carbon footprinting data. For Scope 3, businesses may also need information covering areas such as business travel, waste, purchased goods and services, transport and distribution.

Using consistent data sources and documenting assumptions makes the resulting metric more useful for tracking performance.

Turning carbon intensity into practical action

Calculating carbon intensity should not become a reporting exercise with no follow-up.

Once a business understands its total emissions and how those emissions relate to its activity, it can investigate the areas responsible for the greatest impact and prioritise practical reductions.

Green Economy recommends using carbon footprint data to identify suitable actions and notes that opportunities do not always require significant upfront investment.

Over time, businesses can monitor both absolute emissions and carbon intensity to understand whether those actions are producing meaningful improvements.

How Green Economy can help

Green Economy's carbon footprinting support provides detailed baseline reporting and benchmarking, including measuring a business's carbon footprint or validating existing reports. Its consultants also provide independent validation of Scope 1, Scope 2 and Scope 3 data.

Through sustainability consultancy, Green Economy can help businesses establish their baseline, identify high-impact actions and use data to develop practical carbon reduction projects. Its support is tailored to the organisation's current position and sustainability objectives.