Forwarders and air cargo agents
Every pharma buyer has a new tab in the RFQ, and each one wants the number done differently.
Aviation carbon accounting: air cargo CO2e, airport inventories and CORSIA readiness
Every air waybill now carries a second weight.
Your shipper wants CO2e on every air waybill. Give them a number that survives their auditor.
What do you run?
HOUSE AIR WAYBILL1,250 kg pharma · DEL to FRA via DXB
Ref.
HAWB DEL/FRA/0917
HAWB DEL/FRA/0917
- Gross weight
- 1,250 kg
- Legs
- 2,183 km + 4,844 km
- Distance basis
- Great circle
- Transport work
- 8,784 tkm
- Well-to-wake
- 6.66 t
- Tank-to-wake
- 5.28 t
- Memo, with RF
- 10.31 t
Every leg
Example. Illustrative shipments, sites and flights.
The short answer
How do you calculate CO2e for an air cargo shipment?
Multiply the shipment’s weight in tonnes by each leg’s great circle distance and by an air freight intensity that includes the detour uplift. Use well-to-wake, as ISO 14083 asks. UK 2026 factors give 0.666 kg CO2e per tonne-km on long-haul. Show radiative forcing separately, and add up every leg through the hub.
Last verified 3 October 2026. Sources at the end.
What lands before take-off.
Airport operators
Airlines, ground handlers and concessionaires all sit in our Scope 3. None of them send us data.
Indian airlines flying international
Finance wants the 2027 offset number in the budget. Ops has the fuel. Nobody has both.
Typical requests from shippers, verifiers and finance teams. Illustrative.
One tonne-km by air.
About 34 by sea for the same carbon.
Per tonne-km, well-to-wake: international air freight 0.666 kg CO₂e, an average container ship 0.020 kg (UK government 2026 factors). Sea routes run longer, so compare per lane before you switch.
Same box. Pick the route.
The same box gives very different numbers. Pick the routing and the method.
Free aviation carbon calculator
Your numbers, by the year.
Cargo: tonnes a lane, by routing and method. Airports: Scope 1, 2 and the apron. Airlines: CORSIA offsets and SAF.
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How this is worked out
- Air freight: UK government 2026 factors, per tonne-km. Short-haul under 3,700 km 0.755 (tank-to-wake) plus 0.205 (fuel supply); long-haul 0.531 plus 0.135. With radiative forcing: 1.278 and 0.899.
- Sea comparison: average container ship 0.01977 kg CO2e per tonne-km, well-to-wake, over 11,668 km.
- Airports: grid 0.675 t CO2 per MWh (CEA v22), diesel 2.66 kg a litre, jet fuel 3.18 t CO2e a tonne. APU 120 kg an hour and ground power 90 kW are illustrative.
- CORSIA: fuel × 3.16 t CO2 a tonne × the sector growth factor. SAF cuts 3.16 × SAF tonnes × (1 minus its life cycle value ÷ 89).
- The 2027 growth factor isn’t published yet. Unit prices and the SAF premium are inputs, not forecasts.
Why now
Who’s asking, and by when.
1 Jan 2027
CORSIA turns mandatory
India’s international flights enter CORSIA’s mandatory phase and must offset emissions above the baseline.
1% SAF
Indicative target
India’s targets for international flights: 1% SAF in 2027, 2% in 2028 and 5% in 2030.
15.4%
Offsets now bite
ICAO’s 2024 sector growth factor rose above zero for the first time, so offsets now cost real money.
FY 2026-27
BRSR Core checked
Listed airport operators and airlines in the top 1,000 need Scope 1, 2 and energy assessed or assured.
Answer the shipper’s RFQ with a number.
An EU pharma buyer asks an Indian forwarder for carbon data. Same question, two answers.
RFQ_Annex_C_Carbon.xlsxSheet: Lane list · DEL-FRA
Annex C For each air shipment in the lane list, give greenhouse gas emissions in kg CO2e per ISO 14083 on a well-to-wake basis. State the routing and hubs, the distance method, the emission intensity and its source, and whether radiative forcing is included. Our Scope 3 is assured every year.
Wording modelled on shipper carbon annexes.
- Keep the lane. Send the number with the quote, before the buyer asks.
- Sell the mode shift. Show the shipper what moving a box to sea saves.
Straight answer: we measure and document. We aren’t a CORSIA verification body or an ACA verifier. We get your numbers ready for them.
How it works
From the AWB to the buyer’s form.
Carbon-OS and the Climes Carbon API read your bookings, meters and fuel ledgers. One method for every lane, terminal and route.
Connect
AWB and booking data, energy invoices, GSE logs, fuel ledgers.
Set the boundary
Own operations, tenants, the apron, route pairs.
Calculate
Every method side by side, with sourced factors.
Publish
Shipment statements, ACA and BRSR Core tables, CORSIA planning sheets.
Method and boundary
- Shipments
- ISO 14083 and the GLEC Framework: weight × distance × intensity per leg, well-to-wake. Carrier data first.
- Distance
- Great circle per leg with the UK factors’ 8% uplift, or actual flown distance from the carrier.
- Radiative forcing
- Reported as a memo, never mixed into the ISO 14083 total.
- Airports
- GHG Protocol operational control. ACA Level 3 Scope 3: aircraft, APU, third-party GSE, surface access.
- Scope 2
- Location-based at CEA v22. Market-based from open access and REC evidence.
- CORSIA
- Fuel × 3.16, SAF per the CORSIA eligible fuel formula. Scenarios only. Reports go to your verification body.
- Factors
- More than a million emission factors, including UK government, ICAO and CEA.
What Climes is and isn’t
Your data layer, not your verifier.
What we do
CO2e per air shipment
The Climes Carbon API already prints CO2e per shipment for Indian logistics firms. Air legs use the same engine.
What we do
Inventories and scenarios
Airport Scope 1, 2 and 3 for ACA and BRSR Core. Fuel, SAF and offset scenarios for CORSIA budgets.
What we don’t
Verify or accredit
CORSIA reports go to a DGCA-empanelled verification body. ACA levels come from ACI and its verifiers.
Glossary
Aviation carbon words, made plain.
- CORSIA
- ICAO’s scheme that makes airlines offset international emissions above 85% of 2019 levels.
- Sector growth factor
- The share of this year’s covered emissions above the baseline. It sets each airline’s offset rate.
- SAF
- Sustainable aviation fuel. Under CORSIA, it cuts the offset bill by its life cycle saving.
- Well-to-wake
- Burning the fuel plus producing and moving it. Tank-to-wake is burning only.
- Radiative forcing
- Extra warming from contrails and NOx at altitude, shown as an uplift.
- Tonne-km
- One tonne carried one kilometre. Air freight factors use it.
- ACA
- Airport Carbon Accreditation, ACI’s programme from Mapping to Level 5.
- APU
- The small engine in an aircraft’s tail that powers it at the gate.
Where are you today?
Where do you stand? Three questions.
See where we'd start with you.
Who asks you for aviation carbon numbers?
What data do you hold today?
What’s due first?
Questions aviation teams ask.
How do I calculate CO2e for an air shipment?
Weight in tonnes × leg distance × an air freight intensity, for each leg. UK government 2026 factors give 0.666 kg CO2e per tonne-km well-to-wake for long-haul.
Should radiative forcing be included?
Show it separately. The UK government publishes air factors with and without it, and the uplift is about 1.69 times. ISO 14083 totals use the factor without it.
How much more carbon does air freight emit than sea?
About 34 times per tonne-km: 0.666 kg against 0.020 kg CO2e well-to-wake (UK government 2026).
When does CORSIA apply to Indian airlines?
From 1 January 2027, when the mandatory phase starts, on international flights between participating states.
How is a CORSIA offset requirement worked out?
CO2 on covered flights (fuel × 3.16) × the sector growth factor. The 2024 factor was 0.154. From 2033, 15% follows the airline’s own growth.
What are India’s SAF targets?
India’s indicative targets are 1% on international flights in 2027, 2% in 2028 and 5% in 2030.
How does SAF reduce CORSIA offsets?
By 3.16 × SAF tonnes × (1 minus its life cycle value ÷ 89). 600 t of used-cooking-oil HEFA cuts about 1,600 t.
What do CORSIA units cost?
Phase 1 units traded between USD 10 and 23 a tonne from late 2025 to mid 2026, nearer the low end in July 2026.
Is Climes a CORSIA verifier?
No. We build the fuel and SAF data and the cost scenarios. Your reports go to a DGCA-empanelled verification body.
What does ACA Level 3 need?
Scope 3 including aircraft movements, APU use, third-party ground equipment and passenger surface access, plus stakeholder engagement.
How many Indian airports are at ACA Level 5?
Four, as of November 2025, out of 30 worldwide.
How should we report business flights?
As Scope 3 category 6, by distance and class. Our IT services page shows how.
Bring one lane file. We’ll price every shipment on it.
Twenty minutes. Your lanes, your hubs, your method. You leave with CO2e per air waybill.
Book the 20-minute callor write to carbon-os@climes.io
Sources
- PIB, SAF under the ATF Control Order, 23 April 2026: CORSIA from 2027, SAF targets
- ICAO, CORSIA sector growth factor 2024: 0.154
- ICAO, CORSIA Eligible Fuels leaflet: 3.16, 89, SAF formula
- Norton Rose Fulbright, Taking stock of CORSIA: phases and baseline
- S&P Global, CORSIA unit prices, July 2026: USD 10 to 23
- UK government GHG conversion factors 2026: air freight, sea, jet fuel, diesel
- Airport Carbon Accreditation, Level 3 requirements 2026: Scope 3 sources
- ACI Asia-Pacific, November 2025: ACA Level 5 count
- SEBI circular, 28 March 2025: BRSR Core top 1,000
- CEA CO2 Baseline Database, version 22: grid 0.675
Facts on this page last verified 3 October 2026. Interactive figures are illustrative unless a source is named.