1. How do you calculate the volume of emissions from a flight?
For every 1 kilogramme of jet fuel burnt, approximately 3.15 kilogrammes of carbon dioxide is released into the atmosphere.
The total volume of fuel consumed on a flight depends on factors such as the distance travelled, wind speeds, the loading of passengers and cargo on the aircraft. For our calculation methods we use historic fuel consumption data that allows for the calculation of carbon dioxide emissions. This figure is divided by the number of passengers on the aircraft, based on a historical average for our passenger fleet, and the distance flown, allowing an amount of carbon dioxide per passenger kilometre to be calculated.
2. Is the cargo carried on a flight taken into account when you calculate the passengers' share of fuel consumption?
As part of the calculation method, we discount the emissions associated with any additional cargo which may be carried on a passenger flight. Thus, the fuel use of the cargo is removed when calculating the emissions attributable to the passengers.
3. Why do I need to contribute more if I travel in Business Class or First Class?
Inflight facilities provided for Business Class and First Class passengers differ from those on offer to Economy Class passengers in terms of weight and space. The relative contribution to the aircraft's emissions of a passenger travelling in Business or First Class is greater than that of a passenger travelling in Economy Class so it is therefore considered appropriate to factor this into the calculation.
4. Is the aircraft type taken into account when calculating my contribution, given that some aircraft are more fuel efficient than others?
Fuel consumption per passenger per kilometre is calculated according to the operating data of all aircraft in the Cathay Pacific and Dragonair fleets. Taking aircraft types on individual flights into account would significantly complicate the calculation. Also, for operational reasons we may not use the originally assigned aircraft on particular routes.
5. Do seasonal flight time variations result in any variations in emissions?
Yes. We use actual operating data when calculating emissions, so variations caused by the wind effect on flight time - and the resulting impact on fuel consumption - are taken into account.
6. How are emissions calculated when I travel on multiple sectors?
Our calculator enables you to input your information for multiple sectors in order to get the correct emission calculation. For example, if you travel from Sydney to Hong Kong and then connect to a flight to Beijing, you can input your data for these two sectors into the calculator. If you input this journey as a single sector, Sydney to Beijing, the calculator will automatically assume that your flights will be routed through our Hong Kong hub.
7. What happens when I travel on multiple sectors, but not all of them are Dragonair or Cathay Pacific routes?
You can calculate the Cathay Pacific and Dragonair sectors using our calculator. Our system does not allow sectors which are not flown by Dragonair or Cathay Pacific to be included in the calculation. Should you wish to offset the emissions from your travel on other airlines using our site you may do so by choosing the one-off contribution option.
8. Is there any industry standard used for calculating air travel emissions?
No, there is currently no such standard. Dragonair and Cathay Pacific have worked hard to ensure that the emissions assigned to a passenger are as fair and accurate as possible. The calculation methods will be frequently reviewed, particularly if industry standards become available.
9. How do my emission contributions calculated by Dragonair/ Cathay Pacific compare with those calculated by other airlines?
It is not easy to compare these calculations directly. Different airlines have different ways of calculating emissions. Details such as aircraft type, passenger configuration and cargo load allocations as well as inflight facilities and route structures can vary widely. As mentioned above, we have worked hard to develop an emissions calculator that we feel most accurately and fairly reflects the emissions associated with our fleet and our passengers.
10. How much environmental damage does flying cause?
The Intergovernmental Panel on Climate Change (IPCC), set up by the United Nations and the World Meteorological Organisation, has indicated that aviation currently contributes 2% of global carbon dioxide emissions. There is significant research and investigation on the impacts of other emissions and the release of emissions at high altitude. Given the complexity of chemical reactions in the atmosphere, there remains significant uncertainty around these issues.
11. What's the issue with contrails and cirrus cloud?
Condensation trails (contrails) are the white trails that sometimes form when an aircraft is cruising in cold, humid atmospheres and are believed to be linked to the formation of cirrus clouds - which is thought to be a contributing factor to climate change. Despite significant research in this area, scientists remain uncertain as to the specific contribution of contrails to adverse climate change.
12. How does carbon offsetting work?
Carbon offsetting is an effective means of funding carbon reduction on the ground to compensate for emissions associated with your flight. By paying to offset emissions in our FLY greener carbon offset programme, you are contributing to the purchase of carbon credits generated by projects that reduce the emission of greenhouse gases. These carbon credits are then effectively "retired" to ensure that they cannot be sold or used again.
13. What are carbon credits?
Carbon credits for the purpose of the FLY greener carbon offset programme are verified emissions reductions (VERs) generated from emissions abatement projects verified in accordance with the Voluntary Carbon Standard (VCS) or an equivalent or higher global standard. The VCS developed by The Climate Group, the International Emissions Trading Association (IETA) and the World Business Council for Sustainable Development is aimed at ensuring the integrity of the voluntary offsetting market.
14. How effective are carbon offsetting programmes?
Carbon offsetting is only one way of reducing greenhouse gas emissions. While offsetting doesn't reduce emissions from flying itself, it avoids or reduces the emission of greenhouse gases elsewhere. Offsetting also encourages innovation, raises awareness of the need for better carbon management and in some cases can also contribute to the reduction of local air pollution.
15. What else are Dragonair and Cathay Pacific doing to manage their emissions?
Carbon offsetting is only one way of reducing our carbon footprint. We have been making focused efforts to lower our emissions through changes to our operations, technical advances and fleet development. Our aircraft are subject to comprehensive regular maintenance checks to ensure that they are operating at optimal efficiency. Aircraft in our existing fleet have been re-engineered to improve efficiency where feasible, and our fleet development programme means we are now bringing more efficient aircraft into the fleet. We provide technical support to lobbying efforts for more efficient air traffic management that can limit journey times and reduce fuel consumption.