For organizations prioritizing emissions reduction and sustainability efforts, taking a holistic view of your emissions is essential. That means looking at the total emissions for a given source or scope alongside other key organizational metrics. The two metrics that will help you make the best decisions for decarbonization are absolute- and intensity-based metrics. Each of these types of metrics will provide different inputs to help in your decision-making. As you build your company’s carbon inventory, developing both is recommended.
After your company has gathered its emissions-generating activity data and transformed it into a carbon footprint, the next step is determining how best to manage those carbon emissions. But where is the best place to start? How do you know what efforts and areas will have to biggest impact? Again, understanding absolute emissions vs. carbon intensity will help you answer those questions.
What are absolute emissions?
Absolute emissions metrics indicate the total amount of greenhouse gases (GHGs) emitted into the atmosphere over a specific period. Examples of absolute emissions metrics include your organization’s total GHG emissions for a reporting year or total emissions from a specific source, such as office electricity or fleet vehicles. These are measurements of emissions in units of mass, most commonly metric tons of carbon dioxide equivalence (MT CO2e). When you look at the aggregate emissions from your organization’s GHG inventory, you look at an absolute metric.
What is carbon intensity?
Carbon intensity metrics refer to the amount of greenhouse gas emissions per unit of some activity or output. These metrics express the emissions intensity of a particular process or industry and help normalize emissions due to changes in organizational activity, such as the total growth of a business unit.
Examples of intensity emissions metrics include CO2 emissions per unit of energy produced (CO2e/kWh) or methane emissions per head of cattle (CH4/head). Intensity metrics are often used to compare the emissions performance of different facilities or industries or to track changes in emissions intensity over time, where changes in economic activity can obscure progress. Let’s unpack that with an example: Say a company hires more employees—that typically means total (or absolute) emissions will likely go up. However, the company launched an employee commuting benefit that reduces emissions per full-time employee (FTE). While the company’s absolute emissions rise, its emissions per FTE fall because of that commuting program. Intensity metrics provide the clarity that an action has the intended impact.
Next, let’s take a closer look at the advantages and disadvantages of each type of metric to give you a better sense of when to use one over the other.
Absolute emissions metrics: Pros and cons
Absolute emissions metrics are the cornerstone of carbon accounting, and the first metric stakeholders will look for when understanding your organization’s GHG footprint. The advantages of using absolute emissions metrics include the following:
- Transparency: Absolute emissions provide a clear and straightforward measure of the total amount of GHGs emitted into the atmosphere, which can help to increase transparency and accountability.
- Regulatory compliance: Absolute emissions metrics are often used as the basis for compliance with emissions regulations, such as emissions caps or carbon taxes.
- Target setting: Absolute metrics are the primary metric used to set targets for emissions reduction (e.g., net-zero), such as reducing total CO2 emissions by a certain amount over a specific period. Indeed, most, if not all, reporting and disclosure frameworks, such as SBT and CDP, require organizations to report on their absolute emissions.
- International comparison: Absolute emissions metrics are commonly used in international climate agreements and protocols. They make it easier to compare emissions across countries and regions and track which countries are most responsible for climate change and global temperature rise.
Absolute metrics tell the high-level story of what is happening at the organizational level but do little to provide context on the details inherent in an emissions profile. The disadvantages of absolute metrics include the following:
- Insensitive to efficiency improvements: Absolute emissions metrics do not account for the efficiency or productivity of a facility or industry. Consequently, they do not necessarily reflect improvements in emissions intensity.
- Challenging to achieve: Setting and achieving absolute emissions reduction targets can be difficult in the short term, particularly for industries or sectors with high emissions activities.
- Insensitive to growth: Absolute metrics can mask efficiency improvements in a growing company. A company’s total emissions could increase during a growth stage, even if the organization makes emissions improvements.
- Lack of comparability: Absolute metrics can make it challenging to compare results across sectors since total emissions vary significantly between regions, organizational size, and business models. The total emissions of an oil and gas conglomerate will always outshadow an office-based business, regardless of the activities taken to mitigate those emissions.
Carbon intensity metrics: Pros and cons
Intensity metrics offer a more nuanced view of organizational emissions and can provide additional context to absolute emissions. The advantages of using intensity metrics include the following:
- Reflects efficiency improvements: Intensity emissions metrics take into account the efficiency or productivity of a facility or industry and therefore reflect improvements in emissions intensity, even if overall emissions levels remain the same or increase.
- Easy comparison across industries: Intensity emissions metrics can provide an apples-to-apples comparison using a common denominator, making it easy to assess emissions across different industries or activities.
- Progress tracking: Intensity metrics can be used to track emissions reduction progress over time, regardless of changes in overall production or activity levels.
- Can be used to set achievable targets: Intensity metrics can be used to set intensity targets for emissions reduction, like reducing GHG emissions per unit of energy produced (e.g., energy intensity).
Intensity metrics can hide what is happening at the organizational level. The disadvantages of using intensity emissions metrics include the following:
- Provide a partial picture: Intensity metrics provide only a glimpse of a company’s total carbon emissions.
- Can mask emissions growth: Intensity metrics may mask total emissions growth, particularly in cases where production or activity levels increase rapidly.
- Can be challenging to achieve: Depending on the chosen denominator, setting and achieving intensity reduction targets can be difficult. For example, travel-related metrics depend on scaling new technologies (i.e., fleet vehicle electrification) to achieve significant reductions.
- Can be less transparent: Without clear messaging, intensity metrics can be more complex to understand and communicate than absolute metrics, which can make it more difficult for stakeholders to assess emissions performance.
- Can favor large companies: Intensity metrics, such as the emissions per unit of production, may favor large manufacturers who have achieved economies of scale in their production process.
Common examples of carbon intensity metrics
Carbon intensity metrics come in all shapes and sizes, depending on the industry, source, or measured activity. Some common examples of intensity metrics include:
- Carbon dioxide equivalent emissions per unit of energy produced (CO2e/kWh): This metric is often used to compare the emissions intensity of different power generation technologies or fossil fuel sources.
- Carbon dioxide equivalent emissions per square foot (CO2e/sqft): This metric is often used in commercial real estate and for leased spaces to determine the energy efficiency of buildings and offices. It can show reductions in emissions intensities due to energy conservation measures or green power procurement.
- Carbon dioxide equivalent emissions per passenger-km (CO2e/p-km): This metric is used to compare the emissions intensity of different modes of transportation, like cars, buses, and trains. This is a common metric used to measure improvements in business travel or employee commuting.
- Carbon dioxide equivalent emissions per million dollars of revenue (CO2e/$M): This metric measures the carbon efficiency of a company’s economic output.
- Carbon dioxide equivalent emissions per unit of product (CO2e/product): This metric measures the GHG emissions per product that a company produces. These emissions metrics are the output of a product life-cycle assessment (LCA) and can be used to compare emissions over time or between competing products.
- Methane emissions per unit of livestock produced (CH4/head of livestock): This metric measures the methane emissions intensity of different types of livestock and their food sources.
When should you use these absolute or intensity metrics?
Neither metric—absolute or intensity—is necessarily better than the other. One can be more appropriate depending on the situation. Absolute emissions metrics are best used to provide a full picture of emissions at a particular level, be it company-wide, geographically, source, or scope. Carbon intensity metrics can provide a more nuanced picture of those emissions with respect to a specific activity.
To truly understand your company’s emissions, it is best to develop both metrics and target them at a particular emission source, activity, or geography. This will allow you to track the total reduction in emissions, and the rate of reduction year-over-year, normalized for any economic growth or decline. This type of detailed information is invaluable when demonstrating progress to stakeholders or policymakers.
No matter which emissions metrics are most appropriate for your organization, Sustain.Life can help you measure, manage, and report your emissions with ease.