Specific plane transport

The CORINAIR dataset

The EMEP/CORINAIR Emission Inventory Guidebook (2007) provides detailed fuel consumption data for numerous specific aircraft types. This data is broken down by fuel consumption associated with landing and take off (LTO) phases (taxiing, take off, climb out, landing) and cruising at altitude. LTO fuel consumption is effectively constant for each individual flight, but cruise fuel consumption varies with distance flown and is specified for each aircraft type at specific flight distance intervals (e.g. 250 km, 500 km, ... 6000 km).

The CORINAIR data shows that, while the total fuel consumed during a flight is a function of the flight distance, the rate at which fuel is consumed (per km) during the cruise phase is not constant but also varies with the distance flown. This reflects the additional initial fuel loading required for longer flights. As such, CORINAIR methodology recommends that users interpolate between the distance-fuel consumption datapoints in order to estimate the specific quantity of fuel burned for a given flight distance.

According to CORINAIR methodology, this fuel consumption is converted into CO₂ emissions by using a CO₂ emissions factor of 3.15 (kg CO₂ per kg fuel). This value corresponds to the CO₂ emissions factor for 'jet fuel' specified by the IPCC (1999). This data and methodology therefore provides a calculation of CO₂ emissions on a per aircraft basis, as a function of flight distance.

Radiative Forcing

Uncertainty over the environmental impact of aircraft emissions arises from the complexity of atmospheric chemistry, particularly in relation to the emission of non-CO₂ products (e.g. water vapour, contrails, NO_x) at high altitudes, which is argued to exert a greater global warming effect compared with similar emissions at ground level. These effects can be accounted for by using a multiplicative factor called the Radiative Forcing Index (RFI), which represents the ratio of all radiative forcing (CO₂ + non-CO₂ emissions) to that arising from CO₂ emissions only. Estimates for RFI range between 1 and 4 with a value of 2.7 recommended by the IPCC in 1999. No specific recommended value was quoted in the most recent IPCC report (2007), and the current best estimate for RFI is 1.9 (Sausen et al. (2005)). Following the CORINAIR methodology, Discover returns values for CO₂ emissions only - i.e. with no RFI applied. Users can elect to incorporate the RFI in their calculations however - see specific categories for further details.

See the relevant subcategories for further details on how to use these data and methodologies.