The Economic and Human Cost of Disasters The world is becoming increasing more inhabited which is impacting our environment. This leaves our populations more vulnerable to disasters. In the past 20 years, natural disasters have killed over 3 million people, and inflicted injury, disease, homelessness and misery on over 1 billion people in addition to causing billions of dollars of material damage. In 2004, it was estimated that the annual global economic costs related to disaster events average US$629 billion per year, five times that of 20 years ago. In 2003 there were about 700 natural disasters. Below are a few statistics on the human and economic losses experienced from recent disaster events.
 Figure: Economic losses resulting from natural disasters 1950-2001 Preparedness In years gone by, emergency managers were tasked with focusing on preparing for and responding to emergencies. Today, the emphasis is increasingly on minimizing the effect of disasters before they happen through coordination and cooperation between many agencies, although in light of the recently publicized disasters, much more still needs to be done. Preparation is the key to mitigating disaster events. The World Bank and the USGS in a recent study estimated that economic losses worldwide for natural disasters in the 1990s could have been reduced by $280 billion if $40 billion had been invested in prevention measures. Those organizations taking steps to minimize disaster effects are preparing disaster plans and ultimately working by these plans when an extreme event occurs. Technology is increasingly being used to assist in the preparation of disaster plans, assisting in operational activities following a disaster event, and assisting in the long-term recovery planning and monitoring processes. GIS, with its capability for displaying, managing and modeling spatial data is one of the technology tools increasingly being used. The Disaster Cycle The Office of US Foreign Disaster Assistance describes a disaster in terms of a cycle of emergency management tasks, each preceding task leading to the next. And with each new disaster, further knowledge is attained from the lessons learnt. These can be incorporated back into a disaster plan to improve the preparedness and response measures. The main facets of the disaster cycle are:
Identification & Planning Once an emergency management team/organization has decided to prepare a disaster plan, one of the first steps required is to identify possible hazards, assets at risk and the location of various support facilities. First the extent of the geographic area to be covered by the disaster plan needs to be delineated. This could be an entire country or state, a city, or a local community. Consideration also needs to be given to administrative jurisdictions covered/crossed. Once the extent of the geographic area has been determined, the different types of hazards that can threaten a specific area need to be identified. These can be based on past experiences or the scientific body of knowledge for predicting treats to a specific area. As each geographic area is different, so too are the threats. For example, around the equator there is greater likelihood of severe storms (hurricanes, cyclones, typhoons) and flooding, whilst a location that is surrounded by heavily timbered forests and commonly encounters electrical storms, is more likely to be threatened by fires. Local geography also comes into consideration, e.g. Low lying areas are more subjected to floods than high lying areas. Steep sided slopes in areas of high precipitation are more likely to be subjected to land slides or slippage. The time of year also needs to be considered, e.g. fires are more prevalent late in the summer when grasslands and forests are tinder dry.  Figure: Layers of information utilized in a disaster management system Other types of information that are important for consideration includes infrastructure and facilities data such as the locations and specifics of law agencies, medical facilities, evacuation areas, communications centers, transport networks, emergency power and water supply, shelter areas and burial centers that can be used when an extreme event occurs. In addition, information such as property details, geology, hydrology, soils, vegetation, transport networks, contours, are also useful. Once this information has been collected it can be stored in a GIS where the data can undergo further modeling, analysis and display to help identify if patterns exist as to where and when disasters repeat themselves and which areas are more at risk than others. Mitigation Once the types of hazards likely to impact a given area have been accessed and understood, the areas of most vulnerability can be easily identified from maps. Master plans can be formulated to address these areas of vulnerability. For instance, in flood prone areas, a review of municipal zoning could be undertaken and recommendations made to restrict new buildings in the areas subject to most flood inundation, instead leaving these places as open public areas; river bank levees could be designed and constructed, etc. Mitigation measures are usually left to the local, state or federal authorities. Whilst many authorities in developed nations are now being proactive in taking measures to reduce the impact of disasters, many developing nations are waiting until after an extreme event has occurred before addressing the issue. In either case, GIS analysis is being used to assist authorities identify areas where mitigation effort should be concentrated. The first example shown below depicts areas at risk to flood [red being high risk, yellow being medium risk and green being low risk], whilst the second example shows areas at risk to landslide [areas depicted in orange to red being most at risk]. Using such maps generated by GIS, the authorities can then review policies such as building codes for these specific areas, rezoning effected areas, and/or develop a program of civil works to minimize potential risks. Example 1- Flood risk map  Example 2 – Landslide risk map  Changing building codes so that building structures are raised above flood peaks, building water levees, building basement structures to withstand earthquakes, clearing zones around houses in fire risk areas, are just some of the ways that authorities and individuals are working towards minimizing the impact of extreme events when they occur. Preparedness It is important to subdivide an area up into zones of management and to disseminate this information to the various authorities so that everyone is clear as to who has jurisdiction over an area during an extreme event. Without these management zones, chaos and duplication of effort can result. Within each zone, the number and type of each support facility able to assist in responding to a disaster needs to be delineated on maps and communicated to all concerned authorities. For each management zone, it is important to identify how many and the location of:
 Figure: Results of GIS analysis depicted areas of limited facilities In addition to management zone maps, maps need to be communicated to the general public identifying the location of support facilities / evacuation routes as well as guidelines as what to do when an extreme event occurs. The guidelines will identify who should receive warnings about potential hazards, its severity, when, how often, and by which means – newspapers, TV, radio, or emergency personnel door knocking. The map below shows evacuation routes, points and hospital locations in downtown Charleston to be utilized in Carolina USA in the event of a hurricane. Figure: Evacuation routes, downtown Charleston  |