Greenhouse Gas Emissions
2023 2022 2021 2020 2019
metric tons CO
2
e
metric tons CO2e
metric tons CO
2
e metric tons CO
2
e metric tons CO
2
e
Direct (Scope 1) emissions
36,590,472 30,400,715 21,373,624 15,485,363 34,406,941
Mainline aircraft direct emissions
36,454,532 30,263,431 21,253,385 15,392,492 34,263,909
Conventional jet fuel 36,454,016 30,263,216 21,253,316* 15,392,491* 34,263,908*
Sustainable aviation fuel - CH
4
and N
2
O
517 215 68* 45* 82*
Mainline vehicles (diesel, gasoline, CNG, LPG)
2
52,976 47,447 38,242 24,766 65,161
Facilities (natural gas combustion, engine test cells)
82,964 89,837 81,997 70,797 80,573
Dry ice from catering
0 0 1,720 2,015 4,147
2023 2022
2021 2020 2019
metric tons CO
2
e
metric tons CO2e
metric tons CO
2
e metric tons CO
2
e metric tons CO
2
e
Biogenic emissions - outside of scopes 67,395
26,806 7,768* 5,975* 13,852*
Mainline aircraft emissions - CO
2
from sustainable aviation fuel
67,395
26,806 7,768* 5,975* 13,852*
2023 2022 2021 2020 2019
metric tons CO
2
e
metric tons CO2e
metric tons CO
2
e metric tons CO
2
e metric tons CO
2
e
Indirect (Scope 2) emissions
144,019 149,252 160,794 175,087 189,682
Electricity consumption (location-based)
160,340 166,757 183,311 196,066 201,690
Electricity consumption (market-based)
143,991 149,251 160,794 175,087 189,682
Steam consumption
28 0 0 0 0
2023 2022 2021 2020 2019
metric tons CO
2
e
metric tons CO2e metric tons CO2e
metric tons CO
2
e metric tons CO
2
e
Other Indirect (Scope 3) emissions
12,671,510 13,343,676 11,926,943* 8,982,191* 17,481,978*
3: Mainline aircraft fuel production
7,391,936 7,250,196
5,106,045* 4,701,874* 10,010,679*
Conventional jet fuel
7,377,946 7,246,478 5,104,506* 3,752,824* 8,356,884*
Sustainable aviation fuel
13,990 3,718 1,538* 1,491* 13,653*
4: Regional aircraft direct emissions and fuel production
4,873,562 5,587,322 1,259,152* 94,7558* 7,050,476*
Regional aircraft and bus-operated flights flown under capacity purchase
agreement - direct emissions
4,048,183 4,504,664 5,294,725 4,053,434 7,025,889
Regional vehicles (diesel, gasoline, CNG, LPG)
2
12,799 14,533 15,481 13,658 24,588
Regional aircraft flown under capacity purchase agreement - fuel production
789,189 1,030,688 1,202,863* 908,708* 1,640,141*
Regional aircraft flown on an at-risk basis - fuel production
23,391 37,437 56,289* 38,849* 0*
7: Employee commuting
125,795 111,108 52,278 80,980 176,205
14: Regional aircraft flown on an at-risk basis
122,425 163,902 243,553 0
15: Ownership stake in Azul Brazilian Airlines
156,432 229,912 199,099 132,220 244,605
15: United Airlines Ventures investments
3
1,361 1,236 162 24 12
2023 2022 2021 2020 2019
metric tons CO
2
e
metric tons CO2e
metric tons CO
2
e metric tons CO
2
e metric tons CO
2
e
Gross GHG emissions
49,406,001 43,893,642 33,461,342* 24,647,395* 52,085,532*
Carbon offsets
0 0 0 0 0
Net GHG emissions
49,406,001 43,893,642 33,461,342* 24,647,395* 52,085,532*
Efficiency numbers
2023 2022 2021 2020 2019
Revenue passenger-miles (RPM - millions) - consolidated
244,585 206,791
128,979 73,883 239,360
Metric tons CO
2
e per million RTKs - Mainline + Regional
4
1,056.9 1,097.7 1,106.6** 1,337.7* 1,246.6*
Revenue tonnes-kilometers (RTKs – millions) - Mainline + Regional
46,361 39,526 25,212 15,934 42,760
Available seat-miles (ASMs – millions) - Mainline + Regional
291,566 247,858 178,684 122,804 284,999
Metric tons CO
2
e per million ASMs - Mainline + Regional
168.9 176.2 186.2** 199.6* 181.8*
Energy consumption
2023 2022 2021 2020 2019
Conventional jet fuel - Mainline aircraft (gallons – millions)
3,779 3,139 2,205 1,600 3,562
Sustainable aviation fuel - Mainline aircraft (gallons – millions)
7 3 1 1 1
Lifecycle reduction from SAF
77.9% 86.9%
83.4% 79.3% 62.0%
Emissions reductions from SAF (metric tons CO
2
e)
11,308 3,419
987 1,220 8,517
Conventional jet fuel - Regional aircraft (gallons – millions)
418 466 523 404 729
Electricity (MWh)
434,790 435,259 447,714 477,751 489,197
Natural gas (MM BTUs)
1,481,604 1,628,722 1,494,698 1,264,964 1,432,250
Local air quality
2023 2022 2021 2020 2019
tons tons tons tons tons
NO
x
emissions from mainline aircraft
10,356 14,948 10,813 7,660 14,720
NO
x
emissions (old)
11,554 16,144 11,626 8,565 16,410
Mainline aircraft (jet fuel) 10,356 14,948
10,813 7,660 14,720
Vehicles (diesel, gasoline, CNG, LPG)
2
1,197 1,196
813 905 2,035
Facilities (Natural gas combustion, engine test cells)
156 153 121 130 148
2023 United Airlines Environmental Performance Data
2023 2022 2021 2020 2019
tons tons tons tons tons
SO
2
emissions from mainline aircraft
1,250 1,413 1,022 730 1,426
SO
2
emissions (old)
1,251 1,414
1,022 731 1,427
Mainline aircraft (jet fuel) 1,250 1,413
1,022 730 1,426
Vehicles (diesel, gasoline, CNG, LPG) 0 0
0 0 0
Facilities (Natural gas combustion, engine test cells) 1 1
1 1 1
2023 2022 2021 2020 2019
tons tons tons tons tons
CO emissions from mainline aircraft
9,027 7,805 5,503 3,743 8,010
CO emissions (old)
16,089 16,759 10,507 9,207 21,153
Mainline aircraft (jet fuel) 9,027 7,805
5,503 3,743 8,010
Vehicles (diesel, gasoline, CNG, LPG)
2
6,977 8,864
4,921 5,388 8,175
Facilities (Natural gas combustion, engine test cells) 85 91
83 76 83
Waste management
2023 2022 2021 2020 2019
metric tons metric tons metric tons metric tons metric tons
Waste – total
59,025 25,176 31,407 26,667 53,832
Hazardous and non-hazardous waste generation
19,303 22,399 24,253 15,602 26,621
Catering – Municipal waste
37,014 2,776 10,367 11,066 27,210
Hazardous
Moved to new
category
Moved to new
category
Moved to new
category
Moved to new
category
Moved to new
category
Non-hazardous/other waste
Moved to new
category
Moved to new
category
Moved to new
category
Moved
to new category
Moved
to new category
Recycling – total
9,209 6,112 5,818 4,468 8,332
Non-catering – recycled
5,047 5,255 4,446 3,302 4,489
Catering – recycled
4,158 857 1,372 1,166 3,843
Water consumption
2023 2022 2021 2020 2019
millions of gallons millions of gallons millions of gallons millions of gallons millions of gallons
Billed water consumption
5
429 329 661 484 521
Footnotes:
Totals may not add up due to rounding.
© 2024 United Airlines, Inc. All rights reserved.
united.com
**This calculation has been updated since the publishing of United’s Form 10K to include Scope 3 Categories 3 & 4 for comparability with the 2023 emissions disclosures which include these emission categories.
Inclusion of these Scope 3 emission categories reflects a change in our GHG accounting methodology as referenced in our Corporate Responsibility Report and accurately tracking against our SBTI-validated mid-
term goal.
3. United Airlines Ventures investments in Alder Fuels, Archer Aviation, Boom, Clear, Fulcrum BioEnergy, Heart Aerospace, and ZeroAvia (some of which may not have developed GHG
inventories yet)
4. Intensity metric is used to track United's progress against our SBTi near term target it includes Scope 1, Scope 2, and Scope 3 category 3 and 4 emissions
5. Does not account for all United locations or locations shared with other companies (e.g., airport terminals) and as a result may change considerably from year to year
*This data point has been added or updated to reflect the change in our GHG accounting methodology made in 2023 as referenced in our 2023 Corporate Responsibility Report and
accurately tracking against our SBTi validated mid-term goal.
The data presented herein reflecting United’s 2023 GHG emissions footprint has been internally validated by United Airlines Internal Audit Department and externally verified by our third-
party verification partner ERM CVS. United obtains this third-party verification of our Selected Information 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. https://crreport.united.com/documents/United-Airlines-2023-GHG-ERM-CVS-Assurance-Report.pdf
1. United accounts emissions reductions associated with the use and combustion of sustainable aviation fuel (SAF) to be a Scope 1 reduction, as it is in-sector and a sustainable alternative
to the conventional jet fuel usage that is accounted in the gross emissions of this Scope. This is an interpretation of the GHG Protocol, until such time that an accepted GHG accounting
methodology is developed to reflect in-sector reductions associated to biogenic products.
2. United changed to a more straightforward methodology to determine GHG emissions from GSE starting with 2018 reporting, but has not restated prior years; this change also re-
allocated GHG emissions between Mainline and Regional GSE
