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Annex 2
UNWTO, 9 July 2008
Emission Calculations
The purpose of Annex 2 is to give a comprehensive justification of all methods used and assumptions
made for the calculation of the emissions.
A2.1 General Method for Emission Inventories
Any detailed calculation of emissions from tourism is dependent on the availability of a comprehensive
data set on tourism demand. At the moment, existing data on tourism demand (international and
domestic) present several constraints for emission inventories. UNWTO publishes regularly data
on international tourism at country level (regional and world data on international visitor arrivals,
international tourist arrivals and overnight stays), as well as in an aggregated form, but only limited
information is available on domestic tourism. Another problem complicating calculations is that for
international tourism, though arrivals are recorded for each transport mode, only for air transport data
are available for distances traveled. Comprehensive data on all modes of transport are only available
for EU tourism. 742, 743
For the purpose of this report UNWTO prepared a set of tables with an approximation of consistent
worldwide tourism volumes for the baseline year of 2005 containing data on trip numbers (i.e., not
arrivals, as one trip may account for various arrivals), domestic and same-day trips, as well as data on
average length of stay and air transport distances for major tourism flows based on data from UNWTO,
ICAO and IATA (see Annex 1). For car and other transport modes, the total volume of passenger kilometres
(pkm) was estimated using typical average distances for the respective transport mode (see Section
A2.2.1). Passenger kilometers traveled were then multiplied by emission factors for the respective modes
of transport (see Table 11.2 in Chapter 11).
One of the main problems is to calculate emissions from activities undertaken by tourists at the
destination. Information in this area is very scattered, and there can be huge differences in the energyintensity
of such activities. However, there is evidence that activities contribute only a minor share
to overall emissions from tourism, and the large uncertainty regarding these is likely to only have a
marginal impact on overall emissions.
A2.2 Detailed Calculations
A2.2.1 Transport Modal Split, Volumes and Emissions
In order to calculate emissions, tourist transport volumes (measured in number of trips and pkm) needed
to be split into shares for air, car and other (coach, rail and water), as these means of transport make
substantially different contributions to greenhouse gas emissions, if calculated per pkm (see Table 11.2
in Chapter 11). The goal is, however, to calculate global emissions by multiplying trip numbers by
distance (per trip) and to multiply the kilometers traveled by an emission factor for the respective means
of transport used. To do this, it needs to be considered that there are large differences between high
income and developing countries in terms of transport modes used, the distribution of short- and longhaul
trips, and emission factors for transport, accommodation and other activities. The set of tables
with approximations of consistent worldwide tourism volumes for the baseline year of 2005 (see Annex