Illustrative roadmap to net zero by 2050

Our GHG emissions and carbon footprint in 2024^{Footnote 1}

Tracking our progress toward a 100% reduction in GHG emissions on a net basis

Our reporting methodology aligns with the Greenhouse Gas Protocol’s guidance for corporate best practices in GHG accounting. This supports greater transparency and comparability of the GHG emissions resulting from conventional jet fuel and SAF.

Our 2024 GHG footprint incorporates the emissions from both conventional jet fuel production and combustion, referred to as “well-to-wake” (WTW) emissions. This methodology captures the full lifecycle emissions of jet fuel usage and allows us to chart both Scope 1 and associated Scope 3 emissions reductions from the replacement of conventional jet fuel with SAF.

How we measure our GHG emissions

In May 2023, our 2035 near-term carbon emissions reduction target was validated by the Science Based Targets Initiative (SBTi). This independent verification signifies that our target aligns with the latest climate science and is considered ambitious enough to align with the goal of limiting global warming to well below 2.0°C.^{Footnote 2}

Gross GHG emissions vs. intensity over time

Our overall absolute emissions have increased in 2024, and are expected to increase in the short-term due to growth and limited supply of sustainable alternatives (such as SAF).

However, our emissions intensity decreased in 2024 by 1.4% compared to 2023 in part due to our use of newer, more energy-efficient planes and increased load factors as demand for travel has increased. A visualization of how we could meet our near-term emissions reduction target is detailed in our Illustrative Decarbonization Roadmap.

Footnotes

1. The data presented herein reflecting United’s 2024 GHG emissions footprint has been internally validated by United Airlines Internal Audit Department and externally verified by our third-party verification party ERM. United obtains this third-party verification of our GHG emissions on an annual basis. ERM Certification and Verification Services (ERM CVS, a wholly owned subsidiary of the ERM Group, a global market leader in sustainability services) conducts our emissions verification and provides an ISO 14064-3 limited assurance on our GHG emissions for reporting.
2. United’s complete target, as validated by the SBTi states “United Airlines commits to reduce scope 1, 2, and well-to-wake jet fuel GHG emissions, including scope 3 category 4, upstream transportation and distribution [from regional partner airlines] 50% per revenue ton kilometer (RTK) by 2035 from a 2019 base year. The target boundary includes biogenic emissions and removals from bioenergy feedstocks. Non-CO₂e effects which may also contribute to aviation induced warming are not included in this target. United Airlines Inc. commits to report publicly on its collaboration with stakeholders to improve understanding of opportunities to mitigate the non-CO₂e impacts of aviation annually over its target timeframe.”
3. The Roadmap and forecasts depicted therein are based on United’s current or selected assumptions on relevant matters as of the publication date of this report, including currently available optimistic and medium- to best-case scenario net zero scenarios and pathways, as set forth in further detail below. The Roadmap should be read with the context of each lever’s further description below, each of which is incorporated within the Roadmap. The Roadmap assumes emissions from Scopes 1, 2, and Scope 3, Categories 3 and 4, reflective of United’s current GHG accounting methods. The Roadmap does not include estimates of non-CO₂ effects of aviation though it does include CH4 and N2O. These forecasts were not third-party validated and may change over time to reflect updated projections and assumptions and future conditions, events, and circumstances. United reserves the right to make additions, deletions or other revisions to this roadmap in the future, including changes to the relative weighting of various levers or the addition/deletion of certain levers, as it deems appropriate. The roadmap is based on various aviation net zero scenarios, including the ATAG Waypoint 2050 Report, MPP Making Net Zero Aviation Possible Report, ICCT Vision 2050 Report, FAA Aviation Climate Action Plan and ICAO LTAG Report. The BAU scenario incorporates both United’s network plan estimates as well as current estimates of potential future growth based on U.S. GDP growth estimates from the Congressional Budget Office’s Long-Term Budget Outlook and Boeing. Not reflective of specific UAV portfolio companies, instead reflective of technologies generally accepted in industry and academic literature to be available in the stated timeframe. Excludes emissions from technologies included in UAV portfolio that would provide services outside of United’s current service offerings such as supersonic travel and eVTOLs.
4. Does not include estimates of specific aircraft technology currently under development but rather relies on estimates of both fleetwide intragenerational improvements assuming a combination of technologies and intergenerational improvements to aircraft efficiency consistent with historic leaps in aircraft efficiency. A selection of potential and illustrative technologies are included in ATAG’s Waypoint 2050 report, beginning page 40 here: w2050_v2021_27sept_full.pdf (aviationbenefits.org)
5. Source: 2021 United States Aviation Climate Action Plan (faa.gov)p. 7
6. Source: ATAG’s Waypoint 2050 Report, p. 42
7. United has modelled that, when combined, the assumed fleetwide intragenerational improvements and technologies available to retrofit to improve fuel efficiency, could reduce the total size of United’s business-as-usual emissions footprint by 9.5% by 2050.
8. Source: Boeing Fleet Renewal, https://www.boeing.com/sustainability#sustainable-aerospace.
9. Forecasted emissions reductions are calculated as the difference in emissions given estimated activity in 2050 when calculated with 2019 carbon intensity (on a per ASM basis) versus estimated carbon intensity of renewed fleet in 2050.
10. The hypothetical emissions reductions from operational efficiency improvements reflected in the illustrative decarbonization roadmap reflect measures that can be taken today by both aircraft operators (such as aircraft weight reduction measures) and air traffic management (such as continuous descent and climb and surface congestion management). However, the forecasted emissions reductions do not reflect the potential of advanced, next generation concepts, like Trajectory Based Operations or formation flying.
11. Based on internal modelling of theoretical fleetwide mid-point average for fuel efficiency opportunities.
12. According to Mission Possible Partnership’s 2023 Making Net Zero Aviation Possible report, alternate propulsion aircraft capable of size and range requirements of United’s regional fleet may be available beginning in the 2030s and at scale by 2050.
13. Based on internal United estimates of future SAF uptake representative of the volumes of SAF required to reach United’s 2035 goal. Projected global SAF volumes based on an average of the ATAG Waypoint 2050 and ICAO LTAG Report scenarios with medium attainability. In 2050, the combustion of SAF will still result in GHG emissions from the aircraft engine. These levers assume available GHG accounting methodologies will recognize upstream emissions reductions from SAF thus netting out any emissions from combusting SAF when considering SAF emissions on a lifecycle basis.
14. SAF used by United has up to 85% lower GHG emissions than regular jet fuel when we count all its emissions, all the way from how it’s made and delivered to the airport, to when we use it (these are called ‘lifecycle emissions’). This does not mean our current use of SAF reduces our carbon footprint by 85%, however.
15. United estimates each SAF lever (i.e., today’s commercial SAF, second generation SAF and third generation SAF) contribution to the roadmap through review of publicly available SAF projection forecasts: 1) Waypoint 2050 Report; 2) ICAO LTAG Report; 3) Making Net-Zero Aviation Possible - Aviation Transition Strategy; and 4) ICCT Vision 2050 - Aligning Aviation with the Paris Agreement. United estimates our share of SAF production using historic company SAF consumption, announced SAF policies and future offtake projections. Combined, the calculation results in an approximate 17% reduction in emissions.
16. SAF with greater than 100% emissions reductions refers to alternative jet fuels produced with carbon removals by incorporating carbon dioxide (CO₂) removal into the production process. Carbon removals differ from traditional carbon offsets because they directly remove carbon from the atmosphere and are measurable, quantifiable and durable. The resulting fuel’s emissions reductions can be greater than 100% on a lifecycle basis, if more CO₂ is captured than emitted during production and combustion. As a result, United believes that SAF with such reductions offer one potential option for addressing residual emissions; carbon removal credits offer another option. This lever incorporates a best-case scenario assumption for third generation SAF availability.
17. United anticipates NextGen SAF production scaling based on publicly available SAF projection forecasts (see Footnote 5, CATF Decarbonizing Aviation 2024 Report and IATA’s Direct Air Capture and Storage Report), offtake discussions with NextGen SAF project developers, an assumed progress in renewable energy technologies, advancements in SAF production methods and evolving regulatory standards. ASTM approval for SAF blending limits ensures that aviation fuel, when mixed with SAF, meets safety and performance standards without requiring changes to aircraft or fueling infrastructure.
18. SAF is not used at all airports and United’s SAF supply locations can change periodically.