What is the difference between Scope 3 upstream and downstream emissions?
Scope 3 upstream emissions relate to goods and services your company purchases from suppliers — such as raw materials transported to your facility. Downstream emissions cover outbound logistics, including products shipped from your facility to customers or distribution centres. Both are part of Scope 3 under the GHG Protocol Corporate Standard. See also our Carbon Footprint Calculator (Individual).
What does CO₂e mean, and why is it used instead of just CO₂?
CO₂e stands for carbon dioxide equivalent. It's a standardised unit that expresses the global warming potential of all greenhouse gases — including methane (CH₄) and nitrous oxide (N₂O) — as a single equivalent CO₂ value. Using CO₂e allows you to compare emissions across different transport modes and fuel types on a like-for-like basis.
What is the ISO 14083:2023 standard, and how does it affect my calculation?
ISO 14083:2023 is an international standard for quantifying and reporting greenhouse gas emissions from transport chain operations. It defines consistent methodologies for calculating Well-to-Wheel (WTW), Tank-to-Wheel (TTW), and Well-to-Tank (WTT) emissions. This calculator applies emission factors and distance definitions aligned with ISO 14083:2023, giving you results comparable to industry-standard tools.
What is emission intensity, and how is it calculated?
Emission intensity (EI) measures the CO₂e emitted per tonne-kilometre (g CO₂e/tkm). It is calculated by dividing total CO₂e emissions (in grams) by the tonne-kilometres transported. This metric lets you compare the carbon efficiency of different transport modes or routes regardless of shipment size.
Why does air freight have much higher emissions than ocean freight?
Air freight is significantly more carbon-intensive than ocean or road freight. Typical emission intensity values range from around 500–600 g CO₂e/tkm for air, compared to 10–15 g CO₂e/tkm for container shipping. This is due to the high fuel burn of aircraft engines relative to the payload carried over a given distance.
What is the load factor, and why does it matter?
The load factor is the percentage of a vehicle's maximum payload that is actually used by your cargo. A higher load factor means the emissions are shared across more freight, reducing the per-unit carbon footprint. If you're the only shipper on a vehicle, 100% of emissions are attributed to you; if the vehicle is half-empty, your share is higher than necessary.
Does refrigerated transport produce more emissions?
Yes. Refrigerated (reefer) transport requires additional energy to maintain controlled temperatures, typically adding 10–25% more fuel consumption and emissions compared to standard dry cargo. The exact uplift depends on ambient temperature, insulation quality, and cargo type.
How can I reduce my supply chain emissions?
Key strategies include shifting from air to sea or rail freight, optimising load factors to avoid empty or near-empty vehicles, consolidating shipments, sourcing from closer suppliers to reduce distances, and partnering with carriers using alternative fuels or electric vehicles. Using tools like this calculator helps you identify the highest-emitting parts of your supply chain and prioritise action. You might also find our use the Flight Carbon Footprint Calculator useful.