Fuel efficiency and emissions reduction

Improvements in fuel efficiency

Improving fuel efficiency is critical to our ability to manage our carbon footprint. Here are the actions we take to improve our fuel efficiency.

In the air

Since 1990, we've improved our fuel efficiency by more than 45 percent. United has made significant investments in a modern, fuel-efficient fleet while implementing operational and procedural changes to drive fuel conservation.

Weight reductions

We constantly review the amenities of our aircraft for lighter-weight alternatives, as lighter aircraft consume less fuel and produce fewer emissions. Learn more

Single-engine taxiing

Shutting down one engine and taxiing on the other saves five million gallons per year, or the equivalent of removing 9,000 cars from the road.

Continuous descent approaches

By avoiding applying thrust at low altitudes, aircraft can save fuel—while also reducing noise impacts to cities.

Towing aircraft

Rather than taxiing aircraft between flights, United’s fleet of 69 SuperTugs at 10 airports saves eight million gallons each year by moving nearly 500 aircraft every day between the gates and hangars.

Engine washes

We routinely wash our aircraft engines to reduce drag and emissions.

Auxiliary power unit savings

Where possible, we provide aircraft parked at the gate with air conditioning and electric power via alternative, emissions-reducing methods rather than using the aircraft’s auxiliary power unit.

On the ground and at our facilities

On the ground

Over 4,000 of our ground service equipment (GSE) around the world are electric or use alternative fuels, including high adoption at airports such as Los Angeles (70 percent), Houston (70 percent) and San Francisco (65 percent). United also encourages employee ridesharing, and provides commuter benefits and electric vehicle charging at select locations.

At our facilities

United has LEED certified buildings in Chicago, Houston and San Francisco. One of the largest green roofs in Chicago is on our United Cargo building at O’Hare. Also, we’re conducting an energy efficiency audit on our top 10 energy using facilities in our network, which make up 85 percent of our non-fuel energy use.


Chart, aviation’s impact on the environment.  The entire aviation industry produces approximately two percent of human-induced carbon dioxide emissions. Other industries account for 98 percent of human-induced carbon dioxide emissions. Major contributors include: electricity and heat production, 25 percent; agriculture, forestry and other land use, 24 percent; industry, 21 percent; non air transportation, 12 percent; other energy, 10 percent; buildings, 6 percent.

Aviation’s impact on the environment

Aviation stimulates the economy, trade and tourism, generates business opportunities and enhances quality of life in both developed and developing regions. However, aviation does produce approximately two percent of human-caused CO2 emissions.

We support a global approach to addressing greenhouse gas emissions. Together with other airlines, engine and airframe manufacturers, fuel suppliers, airports and governments, we’re working towards a collective industry goal of 1.5 percent average annual fuel efficiency improvement through 2020, carbon neutral growth beginning in 2020 and a 50 percent reduction in airline CO2 emissions by 2050.

United is involved with the Carbon Disclosure Project (CDP), becoming the first U.S. airline to participate. For additional information on our carbon footprint and climate change strategy, view our latest CDP questionnaire response.

You can also view our entire emissions footprint on our Corporate Responsibility Report. Read more

There are three types of emissions we have, explained below this image. The total emissions for Scope 1, labeled in blue, are 33,273,067 metric tons of carbon dioxide equivalent. The total emissions for Scope 2, labeled in yellow, are 193,476 metric tons of carbon dioxide equivalent. The total emissions for Scope 3, labeled in teal, are 6,669,047 metric tons of carbon dioxide equivalent. There are three types of emissions we have, explained below this image. The total emissions for Scope 1, labeled in blue, are 33,273,067 metric tons of carbon dioxide equivalent. The total emissions for Scope 2, labeled in yellow, are 193,476 metric tons of carbon dioxide equivalent. The total emissions for Scope 3, labeled in teal, are 6,669,047 metric tons of carbon dioxide equivalent. There are three types of emissions we have, explained below this image. The total emissions for Scope 1, labeled in blue, are 33,273,067 metric tons of carbon dioxide equivalent. The total emissions for Scope 2, labeled in yellow, are 193,476 metric tons of carbon dioxide equivalent. The total emissions for Scope 3, labeled in teal, are 6,669,047 metric tons of carbon dioxide equivalent.
Blue - Scope 1

Emissions from sources that are owned and/or controlled by United. This includes:

Jet fuel for United flights -33,273,067*

Sustainable aviation fuel - 2,414

Vehicles - 56,935

Facilities - 84,804

Dry ice from catering - 3,779

*in metric tons CO2e

Yellow - Scope 2

Emissions from the consumption of purchased electricity or other energy sources. This includes:

Electricity consumption - 193,476

Green - Scope 3

Emissions from sources not directly owned and/or controlled by United. This includes:

Regional jet fuel - 6,669,047

Ownership stakes in other companies - 172,851

Vehicles - 25,276

United Global Performance Commitment

Our industry-leading program for select corporate travel partners represents our continued commitment to operational performance excellence throughout the entire travel process. In 2017, United added an environmental commitment that we’ll have a lower gross carbon footprint than American and Delta.

Learn more

United Eco-Skies CarbonChoice carbon offset program

Through the Eco-Skies® CarbonChoice program, United offers customers and businesses the opportunity to purchase carbon offsets to reduce the carbon footprint associated with their air travel and cargo shipments.

Learn more

Emissions and other data

Every year, we report on our carbon emissions, local air quality, waste management, water and energy consumption and more. See the table below for our latest data.

Greenhouse Gas Emissions

Carbon emissions - Direct (Scope 1) emissions
  2018 in metric tons CO2e
2017 in metric tons CO2e
2016 in metric tons CO2e
2015 in metric tons CO2e
2014 in metric tons CO2e
Direct (Scope 1) emissions 33,273,067 32,429,263 31,447,052 31,446,166 31,132,366
Mainline aircraft (conventional fuel) 33,125,136 32,269,841 31,282,902 31,279,288 30,966,621
Mainline aircraft (sustainable aviation fuel)1 2,414 3,822 10,237 0 0
Mainline vehicles (diesel, gasoline, CNG, LPG)2 56,935 69,104 78,196 78,315 75,361
Facilities (natural gas combustion, engine test cells) 84,804 83,100 72,486 88,563 90,384
Dry ice from catering 3,779 3,397 3,231 Not reported Not reported

Carbon emissions - Direct (Scope 1) emissions

  • 2018 in metric tons CO2e

    33,273,067
  • 2017 in metric tons CO2e

    32,429,263
  • 2016 in metric tons CO2e

    31,447,052
  • 2015 in metric tons CO2e

    31,446,166
  • 2014 in metric tons CO2e

    31,132,366

  • 2018 in metric tons CO2e

    33,125,136
  • 2017 in metric tons CO2e

    32,269,841
  • 2016 in metric tons CO2e

    31,282,902
  • 2015 in metric tons CO2e

    31,279,288
  • 2014 in metric tons CO2e

    30,966,621

  • 2018 in metric tons CO2e

    2,414
  • 2017 in metric tons CO2e

    3,822
  • 2016 in metric tons CO2e

    10,237
  • 2015 in metric tons CO2e

    0
  • 2014 in metric tons CO2e

    0

  • 2018 in metric tons CO2e

    56,935
  • 2017 in metric tons CO2e

    69,104
  • 2016 in metric tons CO2e

    78,196
  • 2015 in metric tons CO2e

    78,315
  • 2014 in metric tons CO2e

    75,361

  • 2018 in metric tons CO2e

    84,804
  • 2017 in metric tons CO2e

    83,100
  • 2016 in metric tons CO2e

    72,486
  • 2015 in metric tons CO2e

    88,563
  • 2014 in metric tons CO2e

    90,384

  • 2018 in metric tons CO2e

    3,779
  • 2017 in metric tons CO2e

    3,397
  • 2016 in metric tons CO2e

    3,231
  • 2015 in metric tons CO2e

    Not reported
  • 2014 in metric tons CO2e

    Not reported
Indirect (Scope 2) emissions
  2018 in metric tons CO2e
2017 in metric tons CO2e
2016 in metric tons CO2e
2015 in metric tons CO2e
2014 in metric tons CO2e
Indirect (Scope 2) emissions 171,731 331,527 291,543 283,499 416,062
Electricity consumption (location-based) 193,476 323,889 291,543 283,499 416,062
Electricity consumption (market-based) 171,731 Not reported Not reported Not reported Not reported
Steam consumption 0 7,637 Not reported Not reported Not reported

Indirect (Scope 2) emissions

  • 2018 in metric tons CO2e

    171,731
  • 2017 in metric tons CO2e

    331,527
  • 2016 in metric tons CO2e

    291,543
  • 2015 in metric tons CO2e

    283,499
  • 2014 in metric tons CO2e

    416,062

  • 2018 in metric tons CO2e

    193,476
  • 2017 in metric tons CO2e

    323,889
  • 2016 in metric tons CO2e

    291,543
  • 2015 in metric tons CO2e

    283,499
  • 2014 in metric tons CO2e

    416,062

  • 2018 in metric tons CO2e

    171,731
  • 2017 in metric tons CO2e

    Not reported
  • 2016 in metric tons CO2e

    Not reported
  • 2015 in metric tons CO2e

    Not reported
  • 2014 in metric tons CO2e

    Not reported

  • 2018 in metric tons CO2e

    0
  • 2017 in metric tons CO2e

    7,637
  • 2016 in metric tons CO2e

    Not reported
  • 2015 in metric tons CO2e

    Not reported
  • 2014 in metric tons CO2e

    Not reported
Other Indirect (Scope 3) emissions
  2018 in metric tons CO2e
2017 in metric tons CO2e
2016 in metric tons CO2e
2015 in metric tons CO2e
2014 in metric tons CO2e
Other Indirect (Scope 3) emissions 6,867,174 6,079,488 6,268,793 6,474,314 7,022,328
Regional aircraft and bus-operated flights (conventional fuel) 6,669,047 5,977,955 6,157,267 6,472,504 7,020,223
Regional vehicles (diesel, gasoline, CNG, LPG)2 25,276 1,784 1,847 1,809 2,105
Ownership stakes in other companies 172,851 99,750 109,678 Not reported Not applicable

Other Indirect (Scope 3) emissions

  • 2018 in metric tons CO2e

    6,867,174
  • 2017 in metric tons CO2e

    6,079,488
  • 2016 in metric tons CO2e

    6,268,793
  • 2015 in metric tons CO2e

    6,474,314
  • 2014 in metric tons CO2e

    7,022,328

  • 2018 in metric tons CO2e

    6,669,047
  • 2017 in metric tons CO2e

    5,977,955
  • 2016 in metric tons CO2e

    6,157,267
  • 2015 in metric tons CO2e

    6,472,504
  • 2014 in metric tons CO2e

    7,020,223

  • 2018 in metric tons CO2e

    25,276
  • 2017 in metric tons CO2e

    1,784
  • 2016 in metric tons CO2e

    1,847
  • 2015 in metric tons CO2e

    1,809
  • 2014 in metric tons CO2e

    2,105

  • 2018 in metric tons CO2e

    172,851
  • 2017 in metric tons CO2e

    99,750
  • 2016 in metric tons CO2e

    109,678
  • 2015 in metric tons CO2e

    Not reported
  • 2014 in metric tons CO2e

    Not applicable

Local air quality

Local air quality
  2018 tons
2017 tons
2016 tons
2015 tons
2014 tons
NOx emissions 14,720 14,143 16,823 11,988 11,864
SO2 emissions 1,426 1,366 1,597 1,172 1,170
CO emissions 8,010 7,478 9,058 6,370 6,324

Local air quality

  • 2018 tons

    14,720
  • 2017 tons

    14,143
  • 2016 tons

    16,823
  • 2015 tons

    11,988
  • 2014 tons

    11,864

  • 2018 tons

    1,426
  • 2017 tons

    1,366
  • 2016 tons

    1,597
  • 2015 tons

    1,172
  • 2014 tons

    1,170

  • 2018 tons

    8,010
  • 2017 tons

    7,478
  • 2016 tons

    9,058
  • 2015 tons

    6,370
  • 2014 tons

    6,324

Waste management

Waste - total
 
2018 metric tons
2017 metric tons
2016 metric tons
2015 metric tons
2014 metric tons
Waste — total 61,226 63,986 41,786 43,756
49,948
Hazardous and non-hazardous waste generation 28,075 36,874 16,729 Not reported Not reported
Catering — Municipal waste 33,151 27,112 25,057 Not reported Not reported
Hazardous Moved to new category Moved to new category Moved to new category 2,565 555
Non-hazardous/other waste Moved to new category Moved to new category Moved to new category 41,191
49,393
Recycling — total 9,318 10,307 7,302 14,942
9,329
Non-Catering — recycled 5,046 6,618 4,093 12,840 6,454
Catering — recycled 4,272 3,689 3,209 2,102 2,875

Waste - total

  • 2018 metric tons

    61,226
  • 2017 metric tons

    63,986
  • 2016 metric tons

    41,786
  • 2015 metric tons

    43,756
  • 2014 metric tons

    49,948

  • 2018 metric tons

    28,075
  • 2017 metric tons

    36,874
  • 2016 metric tons

    16,729
  • 2015 metric tons

    Not reported
  • 2014 metric tons

    Not reported

  • 2018 metric tons

    33,151
  • 2017 metric tons

    27,112
  • 2016 metric tons

    25,057
  • 2015 metric tons

    Not reported
  • 2014 metric tons

    Not reported

  • 2018 metric tons

    Moved to new category
  • 2017 metric tons

    Moved to new category
  • 2016 metric tons

    Moved to new category
  • 2015 metric tons

    2,565
  • 2014 metric tons

    555

  • 2018 metric tons

    Moved to new category
  • 2017 metric tons

    Moved to new category
  • 2016 metric tons

    Moved to new category
  • 2015 metric tons

    41,191
  • 2014 metric tons

    49,393

  • 2018 metric tons

    9,318
  • 2017 metric tons

    10,307
  • 2016 metric tons

    7,302
  • 2015 metric tons

    14,942
  • 2014 metric tons

    9,329

  • 2018 metric tons

    5,046
  • 2017 metric tons

    6,618
  • 2016 metric tons

    4,093
  • 2015 metric tons

    12,840
  • 2014 metric tons

    6,454

  • 2018 metric tons

    4,272
  • 2017 metric tons

    3,689
  • 2016 metric tons

    3,209
  • 2015 metric tons

    2,102
  • 2014 metric tons

    2,875

Water consumption

Water consumption
  2018 millions of gallons
2017 millions of gallons
2016 millions of gallons
2015 millions of gallons
2014 millions of gallons
Billed water consumption5 532 493 453 343
355

Water consumption

Billed water consumption5

  • 2018 millions of gallons

    532
  • 2017 millions of gallons

    493
  • 2016 millions of gallons

    453
  • 2015 millions of gallons

    343
  • 2014 millions of gallons

    355

Energy consumption

Energy consumption
  2018
2017
2016
2015
2014
Conventional fuel - Mainline aircraft (gallons – millions) 3,445 3,355 3,260 3,216
3,183
Sustainable aviation fuel - Mainline aircraft (gallons – millions) 1 1 1 0
0
Conventional fuel - Regional aircraft (gallons – millions) 691 621 643 670 722
Aircraft (Mainline jet fuel - gallons - millions) Moved to new category Moved to new category Moved to new category 3,216 3,183
Electricity (MWh) 459,057 734,864 616,396 561,586 763,023
Natural gas (MM BTUs) 1,541,368 1,475,467 1,279,545 1,579,085 1,204,290

Energy consumption

  • 2018

    3,445
  • 2017

    3,355
  • 2016

    3,260
  • 2015

    3,216
  • 2014

    3,183

  • 2018

    1
  • 2017

    1
  • 2016

    1
  • 2015

    0
  • 2014

    0

  • 2018

    691
  • 2017

    621
  • 2016

    643
  • 2015

    670
  • 2014

    722

  • 2018

    Moved to new category
  • 2017

    Moved to new category
  • 2016

    Moved to new category
  • 2015

    3,216
  • 2014

    3,183

  • 2018

    459,057
  • 2017

    734,864
  • 2016

    616,396
  • 2015

    561,586
  • 2014

    763,023

  • 2018

    1,541,368
  • 2017

    1,475,467
  • 2016

    1,279,545
  • 2015

    1,579,085
  • 2014

    1,204,290

Other

Other
  2018
2017
2016
2015
2014
Revenue ton-miles (RTMs — millions)3 25,949 24,796 23,540 23,133
22,471
Metric tons CO2e /1,000 RTMs3 1.289 1.321 1.348 1.372 1.404
Available seat-miles (ASMs – millions)4 275,262 262,386 253,590 250,004 246,020
Metric tons CO2e /1,000 ASMs4 145.7 147.6 149.4 152.8 156.8

Other

  • 2018

    25,949
  • 2017

    24,796
  • 2016

    23,540
  • 2015

    23,133
  • 2014

    22,471

  • 2018

    1.289
  • 2017

    1.321
  • 2016

    1.348
  • 2015

    1.372
  • 2014

    1.404

  • 2018

    275,262
  • 2017

    262,386
  • 2016

    253,590
  • 2015

    250,004
  • 2014

    246,020

  • 2018

    145.7
  • 2017

    147.6
  • 2016

    149.4
  • 2015

    152.8
  • 2014

    156.8

Footnotes

1United's sustainable aviation fuel use stayed approximately the same in 2017 as 2016, however, accounted emissions decreased as United's World Energy supplier achieved certification for their lifecycle emissions reduction

2United changed to a more straightforward methodology to determine GHG emissions starting with 2018 reporting, but has not restated prior years; this change also re-allocated GHG emissions between Mainline and Regional GSE

3Scope 1 + 2 emissions/Mainline RTMs; metric used for tracking progress against industry goal of 1.5%/year efficiency improvement

4Scope 1 + 2 + 3 Regional emissions/Mainline + Regional ASMs; metric used for tracking progress against Global Performance Commitment

5Does 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

Totals may not add up due to rounding.
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