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

Extreme events
UNWTO, 9 July 2008
Impacts and Adaptation at Tourism Destinations
There is high confidence that the most immediate and more significant consequences of climate change
are likely to be changes in the nature of extreme events (e.g., flooding, tropical cyclones, storm surges,
heat waves) and climatic variability (e.g., droughts, and prevailing winds accelerating coastal erosion,
see Figure 9.4). 329, 330, 331, 332 Coastal areas are particularly vulnerable to extreme wind events. Windstorm
disasters account for about one-third of all natural disasters throughout the world (by number,
fatalities and economic losses), whilst accounting for more than two-thirds of the corresponding insured
losses and major wind-storm disasters and the losses generated by them have increased drastically in
recent decades. 333 An increase in the frequency of extreme cyclones has occurred in the last decade
and is projected to continue, bringing more extreme wind events. 334
Figure 9.4 Erosion of shoreline and damage to tourism infrastructure due to hurricane Ivan in
Tobago
Photo credit: Simpson, M. C.
The causal relationship between climate change and the observed increase in extreme events is still under
debate. Some scientists highlight the role of Atlantic Multi-decadal Oscillation patterns, as opposed to
global warming activities, in the recorded 20–30 year storm cycles, the latest of which commenced
in 1995. The heavy hurricane toll of 2004 and 2005 in the Gulf of Mexico is seen as indicative of the
development of this cycle, preceded by the last active cycle during 1940–1960. 335, 336
However, there is much compelling evidence that the current levels of tropical cyclone activity are
largely a response to climate change from anthropogenic causes. 337, 338, 339 In the North Atlantic
regions, the observed 20–30 year variations in tropical cyclone and hurricane frequency over the past
century have been characterised by a 50% increase in cyclone activity with each subsequent multidecadal
cycle through the last 100 years. These increases are closely correlated with increasing sea
surface temperatures (SSTs): “[…] a substantial 100-year trend leading to related increases of over 0.7° C
in SST and over 100% in tropical cyclone and hurricane numbers.” 340 Anthropogenically-produced
greenhouse gases have contributed to a general trend, whereby raised SSTs, and increased tropical
cyclone and hurricane numbers are “[…] substantially influenced by greenhouse warming.” 341
Variations in cyclones, hurricanes and typhoons in many small-island tropical and sub-tropical regions
are dominated by El Nino events and characterised by decadal variability. In addition, increases in
the distribution of tropical storm increases in one area are mirrored by decreases in other areas. 342
Although the number of cyclones and cyclone days has decreased in most areas during the past decade,
there has been a large increase in the number and proportion of extreme hurricanes (categories 4 and
5). 343 These increases in hurricane intensity coincide with an increase in sea surface temperatures.
Sea temperature warming has ranged from 0 to 0.5° C per decade between 1971 and 2004, for the
Caribbean, Indian Ocean and Mediterranean regions. 344 Evidence appears to indicate the correlation
between higher sea temperatures and increasing hurricane intensity, and there appears to be a general
trend towards more frequent intense hurricanes. 345
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