culations on the long-term trends in economic disaster losses adjusted for wealth and population increases, which have been conducted in an effort to separate the effects of change in the frequency or intensity of damaging climate events from the effects of increased exposure and vulnerability, have not attributed the increase in losses to climate change alone, but neither has a role for climate change been excluded (Neumeyer and Barthel, 2011; Intergovernmental Panel on Climate Change, 2012). These studies have not accounted well for vulnerability or for adaptation efforts, and they are limited by poor data availability. Settlement patterns, urbanization, and changes in socioeconomic conditions have influenced the observed trends in the exposure and magnitude of harm from climate events (Intergovernmental Panel on Climate Change, 2012). In particular, rapid urbanization and the growth of megacities, especially in low-income countries, have led to the emergence and growth of highly exposed and highly susceptible urban communities.
As discussed in Chapter 3, projections for the next few decades indicate that there will likely be a continuation of current trends, with greater changes in the frequency, intensity, duration, and spatial extent of some extreme events by the end of the century (Intergovernmental Panel on Climate Change, 2012). Who and what is exposed to an extreme weather or climate event depends on the event. For example, many regions are susceptible to flooding following heavy precipitation events, although the flooding and resulting damage can take a number of forms. The people and places most susceptible to harm when there are changes in the frequency, intensity, duration, and spatial extent of extreme events depend on the event and on local factors. For example, a typhoon coming ashore in the Philippines has very different consequences from one of similar strength striking Japan (United Nations International Strategy for Disaster Reduction, 2009b).
It is important to consider the possibility of compound events (see Chapter 3), such as what occurred in South Australia in January 2009 (Murray et al., 2012). An unprecedented heat wave occurred during a multi-year drought, exposing the area to some of the highest temperatures on record. In central Victoria the 12-year rainfall totals were approximately 10 to 20 percent below the 1961–1990 average (Australian Government, 2009). In Victoria, during the week of the heat wave there was a 25 percent increase in total emergency ambulance dispatches and a 46 percent increase over the three hottest days. There were 980 deaths during the four days of the heat wave, compared with an average of 606 per year over the previous five years. A few days after the heat wave, temperatures spiked again, and the forest fire danger index reached unprecedented levels. High winds caused a power line to break, sparking a wildfire that became one of the largest, deadliest, and most intense firestorms in Australia’s history; 173 people died. The bushfires also destroyed almost 1,660 square miles of