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132 Climate Change and Tourism – Responding to Global Challenges
relatives (VFR) tourism, a value of 100 MJ per trip is assumed, as less energy-intense, family-related
activities will be the focus of this segment. The breakdown of travel purposes for international tourism
was based on UNWTO, 650 with 50% arrivals estimated in 2004 for leisure purposes, 26% for VFR,
health, religion and other and 16% for business. The weighted average energy consumption for tourist
activities is thus estimated to be 170 MJ per trip, corresponding to emissions of 27 kg of CO 2 per trip.
These numbers are valid for international tourists. For domestic tourists in high income economies the
international per day emissions have been multiplied with the average length of stay to calculate the per
trip emissions for activities. This means 11 kg per domestic trip in high income economies. For domestic
tourists in developing countries we again assume the amount of energy associated with tourist activities
to be one quarter of the amount consumed by tourists from high income economies and thus used 2.7
kg per trip. Extrapolated to all 4.75 billion tourist trips in 2005, emissions from tourist ‘activities’ are
estimated to be in the order of 48 Mt CO 2 .
11.1.5 Total CO 2 Emissions and RF from Global Tourism in 2005
Table 11.6 shows the estimated contribution of tourism to global warming (including transport,
accommodation and other tourism activities) in terms of CO 2 emissions as well as of radiative forcing
(RF). The contribution of aviation to RF was derived from existing research. 651 For other means of
transport, for accommodation, and other tourism activities, the RF was calculated proportionally to
these sectors’ contribution to emissions of CO 2 . To do so, the authors have assumed that the growth
rate of emissions from aviation has been equal to that of all other tourism sectors since 1945, as the
calculation of RF is based on accumulated emissions of CO 2 .
Table 11.6 Estimated emissions (a) from global tourism (including same-day visitors), 2005 (b)
UNWTO, 9 July 2008
CO 2
Mt Share in
tourism (%)
Contribution to RF (W/m 2 ) (c)
Excluding
cirrus
Including
maximum
cirrus impact
Air transport 515 40 0.0395 0.0979
Car 420 32 0.0176 0.01973
Other transport 45 3 0.0021 0.0021
Accommodation 274 21 0.0116 0.0116
Other activities 48 4 0.0020 0.0020
Total tourism 1,302 100 0.0734 0.1318
Total world (d) 26,400 – 1.6 1.7 (e)
Share of tourism in total world (%) 4.9 – 4.6 7.8
(a) Estimates include international and domestic tourist trips, as well as same-day visitors (base year 2005).
(b) Colours represent the degree of certainty with respect to the data and underlying assumptions. Green represents a degree of
uncertainty of +/–10%, blue +/–25% and red +100%/–50%.
(c) The share of tourism in total radiative forcing is lower than in CO emissions alone because the global CO emisions account just
2 2
for the year 2005, while radiative forcing gives the impact of all CO emissions accumulated in the atmosphere since the industrial
2
revolution. The contribution for aviation and tourism started to become significant only after 1945, and thus accumulated over a
much shorter timespan.
(d) Annual fossil carbon dioxide emissions (including those from cement production), according to IPCC (2007a), The Physical Science
Basis. 652
(e) This value is higher to account for the impact of cirrus.
As shown in Table 11.6, estimates for CO 2 and RF excluding cirrus are rather good, with an error
margin of up to 25%. Taking into account the respective calculation’s uncertainty, this means that
tourism’s contribution to global CO 2 emissions is estimated to range between 3.9% and 6.0%, while