Aircraft emissions

In 2009, according to the Intergovernmental Panel on Climate Change (IPCC) and the International Energy Agency (IEA), aviation accounted for 649 million tonnes of the global total of around 30 billion tonnes of CO2, equivalent to 2% of global emissions from human activity. As aviation grows to meet increasing demand, the IPCC has forecasted that by 2050, the total of aviation emissions could rise to 3%. Whilst the forecast for 2050 is an estimation, it does highlight the challenge the aviation industry will face over the next 40 years.

Global Man-Made GHG Emissions (%)

  • Global emissions
  • Aviation emissions
Sourcs:IPCC, 2007 and IPCC-AIE2005

Comparison of Aviation CO2 Emissions vs Other Forms of Transport (%)

  • International aviation
  • International marine
  • Road transport
  • Other transport
  • Emissions from other sectors
Source of CO2 data: IEA2010

Uncertainty remains within the scientific community regarding the full impact of other greenhouse gases (GHGs) in the upper atmosphere. In 2007, the IPCC estimated these effects to be two to four times greater than those of aviation’s CO2 emissions alone, and by 2050, aviation’s total climate change contribution, including CO2 and other effects, could rise to 5% (with a worst-case scenario of 15% of human emissions). However, the IPCC acknowledges that there is still uncertainty and the non-CO2 impacts of aviation are the subject of intensive academic research.

Non-CO2 Emissions from Aircraft

Non-CO2 Emissions Nature of Impact
NOx Increases the GHG ozone: warming effect Destruction of methane: cooling effect
Water Vapour Forms condensation trails: in exhaust air. Warming effects dependent on altitude, location and atmospheric conditions
Sulphate Aerosols Reflect incoming solar radiation: cooling effects
Soot Small warming effect

Scource: IPCC

Fuel efficiency strategy

Being highly fuel efficient has long been an embedded culture in our standard operational procedures since our first non-stop long-haul flights from Hong Kong to London in 1980 and Hong Kong to Vancouver in 1983. When we reduced the weight onboard these two routes, it enabled us to offer a unique and competitive service to our customers. Over 35 years, various teams within Cathay Pacific and Cathay Dragon have worked on implementing innovative initiatives into the airline’s standard operating procedures, such as a fuel monitoring system; use of engine core washing; introduction of lighter weight onboard equipment (for example food carts and cargo container boxes); and utilising flight techniques and flight planning systems that reduce the use of This has allowed us to operate our aircraft in a highly efficient manner, and to a certain extent, has played a part in helping to build resilience in the face of adverse conditions, such as additional carbon charges and rising fuel prices.

Our fuel efficiency initiatives in the past three decades reflect the IATA four-pillar strategy:

1. Technology

  • Airframe, engine
  • New fuels
2. Operations

  • Maximum efficiency
  • Minimise weight

3. Infrastructure

  • Air routes, ATM
  • Airport procedures
4. Economic instruments

  • Offsets & trading
  • Incentives

Cathay Pacific and Cathay Dragon performance

In 2016, Cathay Pacific and Cathay Dragon were collectively responsible for emitting 17.2 million tonnes of carbon dioxide (CO2) from jet fuel burn, an increase of 0.8% from 2015. Meanwhile, there was an increase of 0.9% for the amount of passengers and cargo carried on flight. Our fuel efficiency remained steady in relation to capacity (available tonne kilometre, ATK) and traffic carried (revenue tonne kilometre, RTK) respectively over 2015. Since 1988, our total fuel efficiency has improved by 16.8% and 24.9% per ATK and RTK respectively.

  • Total CO2 emissions (measured in ‘000 tonnes)
  • Grammes / RTK
  • Grammes / ATK
  • includes Cathay Dragon since 2007
  • includes testing, training, and wet-lease flights since 2009

New initiatives in 2016

Here is an overview of some of our new initiatives in improving our fuel efficiency.

First A350 delivered

In 2016, we took delivery of 10 Airbus A350-900XWB aircraft, which are equipped with our latest cabins, seat entertainment systems and inflight connectivity. The combination of advanced aerodynamics, lightweight composite materials and the latest Rolls-Royce Trent XWB engines resulted in a 25% reduction in fuel burn compared to existing wide-body aircraft. As well as reducing operating costs, the highly efficient A350 also benefits the environment, with a corresponding cut in CO2 emissions, reduced NOx emissions and a smaller external noise footprint.

Final flight for Boeing 747-400 “Queen of the Skies”

After more than 37 years of service, the iconic Boeing 747 flew its final journey between Hong Kong and Tokyo in October 2016. With its ability to carry more people for far greater distances than its predecessors, the aircraft enabled Cathay Pacific to rapidly expand its network significantly during the 1980s and early 1990s. Now, the more fuel-efficient Airbus A350s and Boeing 777-300ERs will fly in place of the Boeing 747. The Airbus A350s and Boeing 777-300ERs forms the primary backbone of our long-haul fleet.

In addition, we have continued to progress several initiatives to optimise our operations and infrastructure pillars of our climate change strategy.

eEnabled system updates

We continued with the eEnabled Aircraft Programme to facilitate seamless global aircraft connectivity and data sharing across our airlines. We began evaluating other technology solutions, which may reduce the complexity of deployment and enable us to roll out the programme sooner.

Flight efficiency working group

In order to better coordinate, manage and improve our fuel efficiency, we established the Flight Efficiency Working Group in 2014. The cross-departmental team focused on projects in the following areas:

  • Aircraft operations

  • Aircraft weight

  • Aircraft performance

  • Airspace efficiency

  1. Reduced Engine Taxi-In (RETI)

    Total reduced engine operation remained steady, which amounted to a saving of over 3,100 tonnes of fuel.

  2. Lower cabin window blinds

    When the window blinds are lowered during disembarkation, it helps to reduce the rate of temperature, which is beneficial during the heated summer months. A banner ad was introduced in our inflight entertainment system to promote the initiative with our passengers.

  3. Aircraft data analytics

    In partnership with Rolls-Royce, we collected various inflight data parameters across the Cathay Pacific and Cathay Dragon fleet. The result of the data analytics will help us identify areas where we can further improve our operational efficiency.

  4. Engine core washing

    We continued the regular washing of our engines, which removes airborne dust, grease, and other contaminates. A dirty engine reduces its efficiency, leading to more fuel burn and, in turn, more pollution and higher operating costs. Beginning in 2016, to further reduce fuel consumption and improve carbon emission, we have started increasing the frequency of engine washings from every 11 to 16 weeks, to 6 to 11 weeks. We have also begun to implement engine washing at certain outports to increase efficiency, utilising otherwise unused ground time.

Past initiatives

The following are some fuel efficiency improvements implemented in the past 10 years:

Examples of Cathay Pacific & Cathay Dragon initiatives on fuel efficiency Emission savings
Reduced engine taxi-in (RETI) after landing 11,000 tCO2/year
Weight reduction from inflight magazine paper grammage reduction 880 tCO2/year
Modification of engines on our A330 fleet 11,000 tCO2/year
Utilising and manually fine-tuning the flexitrack approach – use of real-time wind data to generate flexible flight tracks for flight planning 607 tCO2 on monitored flights in 2010
Using alternative base coat exterior paint Depends on aircraft type e.g. 134 tCO2 on the A340 in 2008
Core washing engines 105,700 tCO2 since 2010
Weight reductions from catering and food equipment (e.g. lightweight cargo and baggage containers and food carts, cutlery, etc.) 78,460 tCO2/year since 2004


The following are some route improvement initiatives implemented by Cathay Pacific and Cathay Dragon in the past 10 years:

Examples of Cathay Pacific & Cathay Dragon route improvements Emission savings
Asia and Pacific Initiative to Reduce Emissions (ASPIRE) – demonstration flights in 2013 Up to 3,150 tCO2/year
Flexible entry/exit points implementation in China for European flights (Y-1 route) 14,000 tCO2/year
North Pacific route improvements 835 tCO2/year
Flexible entry/exit points implementation in China for European flights (MORIT route) 0.6 to 0.9 tCO2 per flight
Re-design of flight paths over the Pearl River Delta 54,000 tCO2/year
Further North Pacific route improvements (SFO-HKG) 792 tCO2/year

Contributing to climate change science

In 2013, one of our Airbus A330-300 aircraft became the first of its type to be equipped with In-service Aircraft for a Global Observing System (IAGOS) scientific instruments. Since 2013, the aircraft has operated over 1,400 flights, primarily on Australian and Middle East routes from Hong Kong. The Airbus A330-300 is manufactured to complement other similar commercial aircrafts operating on other routes around the world, which will help build a better global picture of climate change. Data on ozone, carbon monoxide, water vapour, and clouds is recorded during take-off, cruising, and landing. The results are transmitted from the aircraft on a daily basis to the IAGOS central database for access by science and policy users, including the provision of useful real time data for weather prediction, air quality forecasting and climate models. The growing IAGOS database will continue to improve our understanding of cloud processes and their impact on climate.

More information can be found at