Weatherrelated natural hazards and climate change

Recent weather-related disasters such as the examples in Chapter 1 have demonstrated the vulnerability of many communities to natural hazards caused by extreme weather: windstorms, floods, hailstorms, snow and ice storms, droughts, wildfires, heatwaves and cold waves. Therefore any increase in the frequency or severity of such events would probably be the most noticeable and damaging aspect of anthropogenic climate change, particularly where vulnerability to these hazards is also increasing (Houghton, 1997, chapters 1 and 6). Moreover, it has been known for some time that because such events are related to extreme statistical fluctuations in the weather about its average values, changes in average weather conditions (e.g. global warming) can be accompanied by significant changes in the frequency of extreme weather events too (Wigley, 1985). It certainly seems that extreme events such as the great storm of 1987 in the UK and the 1988 heatwave in the USA helped to stimulate public concern about climate change in the late 1980s (Ungar, 1999).

Nevertheless, no single weather-related hazard event, however severe, can necessarily be ascribed to climate change - it may just be associated with a large statistical fluctuation within an unchanged climate, or with natural variability of the climate (Box 2.1). Furthermore, any resulting disaster may just reflect the fact that the event happened to affect a large or vulnerable population centre. Similarly, although there have been dramatically rising trends in weather-related disasters and insurance losses over the past few decades (Downing et al., 1999a; Kunkel et al., 1999), these may not necessarily be the result of climatic effects. For example, Changnon et al. (2000) summarise recent research showing that in the USA, such trends can largely be explained by societal and insurance factors, with most studies showing an overall increase in vulnerability to weather-related extremes. To help with such assessments, and to help determine what the future holds, two important goals for climate researchers are to quantify any observed changes in the frequency or severity of these exceptional events, and to predict accurately any future trends in a world where global warming is a reality. This chapter and the next explore these issues, Chapter 2 concentrating on windstorms and Chapter 3 on floods and other weather-related hazards. We build on reviews of observed trends and model predictions by

Continue reading here: Box Climatic oscillations

Was this article helpful?

0 0