IPCC Fourth Assessment Report: Climate Change 2007

6.5.2 Socio-economic consequences under current climate conditions

Under current climate conditions, developing countries bear the main human burden of climate-related extreme events (Munich Re Group, 2004; CRED, 2005; UN Secretary General, 2006a). But it is equally evident that developed countries are not insulated from disastrous consequences (Boxes 6.4 and Chapter 7, Box 7.4). The societal costs of coastal disasters are typically quantified in terms of property losses and human deaths. For example, Figure 6.9 shows a significant threshold in real estate damage costs related to flood levels. Post-event impacts on coastal businesses, families and neighbourhoods, public and private social institutions, natural resources, and the environment generally go unrecognised in disaster cost accounting (Heinz Center, 2000; Baxter, 2005). Finding an accurate way to document these unreported or hidden costs is a challenging problem that has received increasing attention in recent years. For example, Heinz Center (2000) showed that family roles and responsibilities after a disastrous coastal storm undergo profound changes associated with household and employment disruption, economic hardship, poor living conditions, and the disruption of pubic services such as education and preventive health care. Indirect costs imposed by health problems (Section result from damaged homes and utilities, extreme temperatures, contaminated food, polluted water, debris- and mud-borne bacteria, and mildew and mould. Within the family, relationships after a disastrous climate-related event can become so stressful that family desertion and divorce may increase. Hence, accounting for the full range of costs is difficult, though essential to the accurate assessment of climate-related coastal hazards.

Figure 6.9

Figure 6.9. Real estate damage costs related to flood levels for the Rio de la Plata, Argentina (Barros et al., 2006).

Tropical cyclones have major economic, social and environmental consequences for coastal areas (Box 6.4). Up to 119 million people are on average exposed every year to tropical cyclone hazard (UNDP, 2004). Worldwide, from 1980 to 2000, a total of more than 250,000 deaths were associated with tropical cyclones, of which 60% occurred in Bangladesh (this is less than the 300,000 killed in Bangladesh in 1970 by a single cyclone). The death toll has been reduced in the past decade due largely to improvements in warnings and preparedness, wider public awareness and a stronger sense of community responsibility (ISDR, 2004). The most-exposed countries have densely populated coastal areas, often comprising deltas and megadeltas (China, India, the Philippines, Japan, Bangladesh) (UNDP, 2004). In Cairns (Australia), cyclone experience and education may have contributed synergistically to a change in risk perceptions and a reduction in the vulnerability of residents to tropical cyclone and storm surge hazards (Anderson-Berry, 2003). In Japan, the annual number of tropical cyclones and typhoons making landfall showed no significant trend from 1950 to 2004, but the number of port-related disasters decreased. This is attributed to increased protection against such disasters. However, annual average restoration expenditures over the period still amount to over US$250 million (Hay and Mimura, 2006).

Between 1980 and 2005, the United States sustained 67 weather-related disasters, each with an overall damage cost of at least US$1 billion. Coastal states in the south-east US experienced the greatest number of such disasters. The total costs including both insured and uninsured losses for the period, adjusted to 2002, were over US$500 billion (NOAA, 2007). There are differing views as to whether climatic factors have contributed to the increasing frequency of major weather-related disasters along the Atlantic and Gulf coasts of the USA (Pielke Jr et al., 2005; Pielke and Landsea, 1998). But the most recent reviews by Trenberth et al. (2007) and Meehl et al. (2007) support the view that storm intensity has increased and this will continue with global warming. Whichever view is correct, the damage costs associated with these events are undisputedly high, and will increase into the future.

Erosion of coasts (Section is a costly problem under present climatic conditions. About 20% of the European Union’s coastline suffered serious erosion impacts in 2004, with the area lost or seriously impacted estimated at 15 km2/yr. In 2001, annual expenditure on coastline protection in Europe was an estimated US$4 billion, up from US$3 billion in 1986 (Eurosion, 2004). The high rates of erosion experienced by beach communities on Delaware’s Atlantic coast (USA) are already requiring publicly funded beach nourishment projects in order to sustain the area’s attractiveness as a summer resort (Daniel, 2001). Along the east coast of the United States and Canada, sea-level rise over the last century has reduced the return period of extreme water levels, exacerbating the damage to fixed structures from modern storms compared to the same events a century ago (Zhang et al., 2000; Forbes et al., 2004a). These and other studies have raised major questions, including: (i) the feasibility, implications and acceptability of shoreline retreat; (ii) the appropriate type of shoreline protection (e.g., beach nourishment, hard protection or other typically expensive responses) in situations where rates of shoreline retreat are increasing; (iii) doubts as to the longer-term sustainability of such interventions; and (iv) whether insurance provided by the public and private sectors encourages people to build, and rebuild, in vulnerable areas.