Climate Change and Tourism - UNEP - Division of Technology ...

UNWTO, 9 July 2008
Advances in Climate Change Science and Implications for the Tourism Sector
Figure 8.2 Scenarios for global temperature in the 21st century
Source: IPCC 2007a
Stabilization scenarios also explore a wide range of future GHG conditions, typically ranging from
atmospheric CO 2 concentrations of 450 ppm to 1000 ppm (current levels are estimated at 380 ppm).
Some stabilization scenarios can be considered proxies for ‘policy scenarios’ because they are very near
to the objectives of some governments in developed countries: they imply that emissions per unit of
GDP would need to be just one quarter of current level by 2050. 166 Such stabilisation scenarios require
very ambitious GHG reductions policies to control energy demand, produce carbon neutral energy,
capture and store CO 2 from energy production.
Analogues
Another approach to describe what future climate conditions might be like is to refer to similar conditions
when they occurred in the past. This approach facilitates more effective communication with some
audiences. For example, one can point out that if global average temperatures were approximately 5° C
cooler, then climate conditions would resemble those during the last ice age and that the changes we
may witness by the end of the 21st century are of a similar magnitude but in the opposite direction.
Another example is the European heat wave of 2003, which is an analogue for average summer
temperature conditions the region might face in the later decades of this century. Under certain climate
change scenarios the annual mean temperature of Paris would be near to that of Toledo now (Figure
8.3). 167 The use of climate analogues assumes that major climate processes remain stable, whereas
unprecedented CO 2 concentrations associated with high GHG emission scenarios may trigger new and
uncertain climate processes. 168
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