Scope 3 Category 4: How to calculate upstream transportation and distribution emissions
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Scope 3 Category 4 covers emissions from relevant transportation and distribution activities carried out using vehicles and facilities outside a business's ownership or control. This can include deliveries from suppliers, outsourced warehousing and purchased freight services.
Calculating these emissions involves identifying relevant logistics activities, gathering transport data and applying suitable emissions factors.
Scope 3 Category 4 covers upstream transportation and distribution emissions associated with a business's purchased products and logistics services.
These are indirect emissions generated by transportation and distribution providers rather than sources owned or controlled by the reporting organisation.
Category 4 can include the movement of purchased goods from direct suppliers to business premises, as well as transportation and distribution services purchased by the organisation.
It also covers relevant third-party warehousing and distribution activities.
Although the category is described as upstream, it can include certain outbound deliveries where the reporting business purchases the transportation service.
Understanding this distinction is essential for classifying emissions correctly.
The activities included depend on how the business purchases, stores and transports goods.
Relevant examples can include:
For example, a manufacturer might purchase transport services to move raw materials from a supplier to its factory.
A retailer could also purchase logistics services to distribute products from its warehouse to customers.
Where these activities meet the Category 4 reporting boundary, their associated emissions should be considered.
Category 4 and Category 9 both cover transportation and distribution, but they have different reporting boundaries.
Category 4 includes relevant transportation of purchased products and transportation or distribution services purchased by the reporting business.
Category 9 covers downstream transportation and distribution of sold products where the transportation services are not purchased by the reporting business.
For example, if a business pays a third-party logistics provider to deliver products to customers, the emissions generally fall within Category 4.
If a customer arranges and pays for transportation after purchasing the products, the associated emissions may fall within Category 9.
The distinction depends on the activity and reporting boundary, not simply whether the goods are travelling towards or away from the business.
Not all transport emissions belong in Scope 3 Category 4.
Fuel burned in vehicles owned or controlled by the reporting business is generally included in Scope 1.
Electricity used by electric vehicles owned or controlled by the business is generally accounted for under Scope 2, where applicable.
Business travel and employee commuting are also reported separately under their respective Scope 3 categories.
The production of purchased goods is generally covered by Category 1 or Category 2, rather than being included again as part of Category 4 transport operations.
Establishing these boundaries helps businesses avoid omissions and double counting.
The information required depends on the logistics activities involved and the calculation method selected.
Useful records can include:
Procurement, finance and logistics teams may already hold much of this information.
Where transport providers manage the journeys, businesses may need to request additional records directly.
There are three main approaches to calculating transportation emissions within Category 4.
These are the fuel-based method, distance-based method and spend-based method.
The most suitable approach depends on the availability and quality of transport data.
Businesses may need to use different approaches for different logistics activities, particularly where some providers supply detailed fuel information while others only provide invoices or shipment records.
The fuel-based method uses information about the fuel consumed during relevant transportation activities.
The quantity of fuel is multiplied by an appropriate emissions factor to estimate the associated greenhouse gas emissions.
For example, where a logistics provider can identify the litres of diesel consumed while transporting goods for a customer, this information can support a fuel-based calculation.
This approach can be useful when reliable fuel consumption data is available.
Businesses should ensure the information relates to the relevant transportation activity and that emissions are allocated appropriately where vehicles carry goods for several customers.
The distance-based method uses the distance travelled, the weight of goods transported and the freight mode.
A common calculation is:
Emissions = freight weight × distance travelled × appropriate emissions factor
For example, transporting 10 tonnes of materials over 100 kilometres represents 1,000 tonne-kilometres.
That activity figure can then be multiplied by a suitable emissions factor for the relevant freight mode.
The emissions result depends on the factor used, so the tonne-kilometre figure alone does not represent the amount of carbon emitted.
This method can be useful when businesses have shipment records but cannot obtain actual fuel consumption data.
The spend-based method estimates emissions using expenditure on transportation and distribution services.
The amount spent is multiplied by a relevant emissions factor expressed per unit of monetary value.
For example, a business may use its annual road freight expenditure to estimate associated emissions where detailed shipment information is unavailable.
This can provide an initial estimate, particularly for organisations managing several logistics providers.
However, transport prices can change without a corresponding change in physical emissions.
For significant logistics activities, businesses should consider replacing spend-based estimates with more representative activity data when possible.
Category 4 can also include relevant energy consumption associated with third-party storage and distribution facilities.
For example, a business may use an outsourced warehouse to store purchased products before they enter its operations or as part of a purchased distribution service.
The calculation may involve gathering electricity, heating or fuel consumption data associated with the storage activity.
Where a warehouse serves several customers, an appropriate allocation method may be needed to estimate the share attributable to the reporting business.
Businesses should document the allocation method and avoid claiming that the warehouse's entire emissions footprint belongs to one customer.
Some Category 4 information may be held by suppliers, freight operators or third-party logistics providers.
Businesses should begin by identifying their most significant transport relationships and asking what information is already available.
Useful requests might include:
Not every provider will have the same reporting capabilities.
Starting with major logistics providers can make the process more manageable and help businesses improve the quality of their calculations over time.
Double counting can occur when businesses combine transport data from several sources without checking what each figure includes.
For example, a supplier's product emissions data may already include certain transportation activities.
A logistics provider's reported emissions may also cover several journeys, customers or stages of distribution.
Businesses should establish which activities are included in each dataset before combining the figures.
It is also important to separate company-controlled vehicles from third-party transportation and distinguish Category 4 activities from Category 9.
Maintaining clear calculation records helps make the results more transparent and easier to review.
Incomplete logistics information is a common challenge when measuring Scope 3 emissions.
Some businesses may have detailed freight records but limited fuel data. Others may only have transport invoices or purchasing information.
Where more accurate activity data is unavailable, an appropriate spend-based estimate can provide a starting point.
Businesses should record assumptions, identify data gaps and explain which calculation methods have been used.
Over time, working with suppliers and logistics providers can help replace estimates with more representative information.
The aim is to develop a reliable calculation that improves as the organisation's reporting processes become more established.
Once emissions have been calculated, businesses can identify which transport activities contribute most to their footprint.
Potential reduction opportunities may include:
The most suitable measures will depend on the organisation's operations, delivery requirements and supply chain.
Businesses should assess potential changes against actual transport data rather than assuming every operational adjustment will produce a measurable emissions reduction.
Category 4 emissions should be calculated consistently across the organisation's chosen carbon reporting periods.
Annual measurement can help businesses understand how changes in logistics activity affect their wider carbon footprint.
However, comparisons should account for changes in freight volumes, calculation methods and data quality.
For example, replacing a spend-based estimate with actual fuel consumption data may change the reported figure without indicating that transport operations have become more or less efficient.
Documenting these changes helps businesses distinguish improvements in reporting accuracy from genuine emissions reductions.
Green Economy's carbon footprinting support helps businesses measure and understand Scope 1, Scope 2 and Scope 3 emissions, including those associated with their wider supply chains.
Its guidance on measuring Scope 3 emissions explains how organisations can identify relevant value-chain activities and improve emissions data collection.
Businesses can also explore Green Economy's guide to the data needed for a business carbon footprint to understand which operational and supplier records can support carbon reporting.
For organisations developing a wider reduction strategy, its advice on including Scope 3 emissions in your carbon reduction plan explains how indirect emissions can inform practical environmental objectives.
Understanding upstream transportation and distribution emissions gives businesses a stronger basis for improving logistics data, engaging suppliers and identifying opportunities to reduce their wider carbon impact.
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