Carbon Offsetting & Air Travel
Part 1: CO2-Emissions Calculations
May 2008, SEI Discussion Paper
Anja Kollmuss (SEI) and Jessica Lane
This is the first of two papers that examine the key factors that have to be taken into account when calculating air travel emissions for the purpose of climate footprint and offset calculations. It examines methods of calculating CO2 emissions only, and provides a framework for how to allocate responsibility for these emissions among various aviation users. The aircraft parameters discussed are:
1. Aircraft Model
2. Flight Profile and Flight Distance
3. Cargo on Passenger Flights
4. Seat Occupancy Rate (Load Factor)
5. Seat Class
The final section of the paper analyzes emissions calculations for flights between three city pairs, and compares the results of three airtravel emissions calculators (Atmosfair, TRX Travel Analytics, Virgin Atlantic) to each other as well as to the UK’s Department for Environment, Food and Rural Affairs (DEFRA) multiplier for air travel emissions calculations.
UPDATE
May 29, 2008
This paper was originally put in the public domain in early May 2008. Since then we have received a number of comments and questions. All three air travel emissions calculator developers were invited to comment on the paper. Atmosfair and TRX Travel Analytics have sent us detailed comments and raised a number of interesting discussion points. Therefore we have decided to revise the document to include the most important comments.
The goal is to use this paper as a discussion document in order to facilitate feedback from experts in the field and in order to gain more clarity about the issues discussed here.
You can send your comments to anja.kollmuss@sei-us.org