Businesstravel Air Internationalfirst emission factor trends — Global
The UK’s business travel footprint shows that international first‑class air travel remains a small but highly emissions‑intensive portion of travel-related emissions. The 2016–2024 trend for the international first‑class flight emission factor moves from about 0.548 to a high near 0.562 in 2021–2022, before easing to around 0.539 in 2023–2024, indicating that fleet efficiency gains and shifts in premium travel demand have partially offset growth in emissions. BEIS/DEFRA’s GHG Conversion Factors for Company Reporting state that “emissions from air travel are calculated from fuel burn and occupancy and vary by seating class” (BEIS/DEFRA, GHG Conversion Factors for Company Reporting, 2024). ICAO also notes that “improvements in aircraft efficiency have not fully offset rising demand for international aviation” (ICAO, 2023). In the UK context, this trend is relevant across all regions and aligns with policy aims to decarbonise aviation while allowing necessary business mobility.
- Category
- Business travel
- Geography
- Global
- Unit
- kgCO2e / km
- Baseline
- Baseline 2024 → 2050
- Last updated
- Updated
Regions covered: All regions
Projection chart
Cumulative percentage change in the emission factor from the 2024 baseline. Shaded band shows min–max range; bold line is the Viable Pathway mid projection.
Data table (Viable mid projection)
| Year | Min | Viable mid | Max |
|---|---|---|---|
| 2024 | 0.0% | 0.0% | 0.0% |
| 2025 | 0.0% | -0.3% | -1.4% |
| 2026 | -0.4% | -0.9% | -2.8% |
| 2027 | -0.7% | -1.6% | -4.1% |
| 2028 | -1.1% | -2.1% | -5.3% |
| 2029 | -1.5% | -2.7% | -6.5% |
| 2030 | -1.9% | -3.3% | -7.5% |
| 2031 | -2.2% | -3.8% | -8.6% |
| 2032 | -2.6% | -4.4% | -9.5% |
| 2033 | -3.0% | -5.6% | -10.4% |
| 2034 | -3.4% | -6.2% | -11.2% |
| 2035 | -3.7% | -6.7% | -12.0% |
| 2036 | -4.1% | -7.1% | -12.7% |
| 2037 | -4.5% | -7.6% | -13.4% |
| 2038 | -4.8% | -8.1% | -14.0% |
| 2039 | -5.2% | -8.5% | -14.5% |
| 2040 | -5.6% | -9.0% | -15.0% |
| 2041 | -6.0% | -9.4% | -15.4% |
| 2042 | -6.3% | -9.8% | -15.8% |
| 2043 | -6.7% | -10.2% | -16.2% |
| 2044 | -7.1% | -10.7% | -16.5% |
| 2045 | -7.5% | -11.8% | -16.7% |
| 2046 | -7.8% | -12.2% | -16.9% |
| 2047 | -8.2% | -12.5% | -17.0% |
| 2048 | -8.6% | -12.9% | -17.1% |
| 2049 | -8.9% | -13.3% | -17.2% |
| 2050 | -9.3% | -13.6% | -17.2% |
How the Viable mid projection is calculated
Weighted projection based on pedigree quality assessments, normalised to 2024 emission factor
Sources and scenarios
| Scenario | Source | Type | Ambition | Pedigree |
|---|---|---|---|---|
|
DESNZ_Historic
Historic reductions from previous years projected linearly forwards. |
UK Department for Energy Security and Net Zero
From 2016 to 2024, the international first class emission flight factor has changes thus: 0.54846 0.55209 0.55987 0.55376 0.55695 0.56251 0.56251 0.5385424 0.53854 |
historic | base | 1.3512498725672673 |
|
McKinsey_NaturalLimits
One scenario for the future is fuel efficiency gains reducing from 1.5% per year in 2024 down to 0% in 2050. |
McKinsey & Company
According to a McKinsey analysis, carriers reduced their fuel consumption per passenger-kilometer by approximately 39 percent between 2005 and 2019 (pre-COVID-19), a compound annual growth rate of about 3.4 percent per year. The challenge moving forward is that the easy gains have already been captured, and airlines are starting to bump up against the natural limit of some of the improvement levers they used to achieve those gains. One scenario for the future is fuel efficiency gains reducing from 1.5% per year in 2024 down to 0% in 2050. |
forecast | modest | 2.596702859842573 |
|
ICCT_CurrentCommitments
The ICCT in Sept 2025 set out varying scenarios for the aviation industry. Under the Current Commitments scenario, from 2025 to 2050 the additional millidegrees Celsius (mC) of warming is projected to drop from 0.118 down to 0.107. |
International Council on Clean Transportation
The ICCT in Sept 2025 (Aviation Vision 2050) set out varying scenarios for the aviation industry. Under the Current Commitments scenario, from 2025 to 2050 the additional millidegrees Celsius (mC) of warming is projected to drop from 0.118 down to 0.107. |
forecast | modest | 2.090430209476521 |
|
ICCT_GHGForward
The ICCT in Sept 2025 set out varying scenarios for the aviation industry. Under the GHG Forward scenario, from 2025 to 2050 the additional millidegrees Celsius (mC) of warming is projected to drop from 0.118 down to 0.089. |
International Council on Clean Transportation
The ICCT in Sept 2025 (Aviation Vision 2050) set out varying scenarios for the aviation industry. Under the GHG Forward scenario, from 2025 to 2050 the additional millidegrees Celsius (mC) of warming is projected to drop from 0.118 down to 0.089. |
forecast | ambitious | 2.090430209476521 |
|
ICAO_NetZeroAspiration
The ICAO Net Zero Aspiration is a unrealistic scenario that states what emission factor trends are needed for global net zero by 2050. |
International Civil Aviation Authority
The ICAO aspirational net zero 2050 goal is a commitment by its member states to achieve net-zero carbon emissions from international aviation by 2050. Adopted in October 2022, this goal supports the Paris Agreement's temperature objectives by emphasizing a collective responsibility for climate action within the aviation sector, though it remains non-binding and lacks specific obligations for individual states. This is equivalent of emission factors reducing from index 1 in 2022 to 0.1 in 2050. |
forecast | unrealistic | 3.496960589918261 |
|
ViablePathway_WorstCase
This scenario assumes a 'fossil-fueled development' narrative with rapid growth in fossil fuel use, and no further reductions in flight emission factors. |
Viable Pathway
This scenario assumes a 'fossil-fueled development' narrative with rapid growth in fossil fuel use, and no further reductions in flight emission factors. |
forecast | pessimistic | 3.496960589918261 |
Changelog
- — Updated vpmid mid from blended projection (len=27); appended source1 from UK Department for Energy Security and Net Zero (historic) year=2024, pedigree_score=1.3512498725672673.
- — Updated vpmid mid from blended projection (len=27); appended source2 from McKinsey & Company (forecast) year=2022, pedigree_score=2.596702859842573.
- — Updated vpmid mid from blended projection (len=27); appended source3 from International Council on Clean Transportation (forecast) year=2025, pedigree_score=2.090430209476521.
- — Updated vpmid mid from blended projection (len=27); appended source4 from International Council on Clean Transportation (forecast) year=2025, pedigree_score=2.090430209476521.
- — No update of vpmid mid from unrealistic and unsubstantiated net zero ambition from source5 International Civil Aviation Authority (forecast) year=2022, pedigree_score=3.496960589918261.
Frequently asked questions
What is driving businesstravel air internationalfirst decarbonisation in Global?
The UK’s business travel footprint shows that international first‑class air travel remains a small but highly emissions‑intensive portion of travel-related emissions. The 2016–2024 trend for the international first‑class flight emission factor moves from about 0.548 to a high near 0.562 in 2021–2022, before easing to around 0.539 in 2023–2024, indicating that fleet efficiency gains and shifts in premium travel demand have partially offset growth in emissions. BEIS/DEFRA’s GHG Conversion Factors for Company Reporting state that “emissions from air travel are calculated from fuel burn and occupancy and vary by seating class” (BEIS/DEFRA, GHG Conversion Factors for Company Reporting, 2024). ICAO also notes that “improvements in aircraft efficiency have not fully offset rising demand for international aviation” (ICAO, 2023). In the UK context, this trend is relevant across all regions and aligns with policy aims to decarbonise aviation while allowing necessary business mobility.
How does Viable Pathway calculate the mid projection?
Weighted projection based on pedigree quality assessments, normalised to 2024 emission factor
Discussion
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