Geographic Perspectives on Sustainability and Human-Environment Systems

Vulnerability to Natural Hazards


The concept of vulnerability encompasses a variety of definitions. In general, vulnerability means the potential to be harmed. Vulnerability to natural hazards is thus the potential to be harmed by natural hazards. Some people and places are more vulnerable to certain hazards than other people and places. While any one extreme event may be unusual, there are broad trends in natural hazards. These trends are due to characteristics of both natural systems and human systems. By characterizing these trends, we can understand who and what is vulnerable and in what ways they are vulnerable. This, in turn, helps us reduce vulnerability and, when extreme events occur, reduce the damage. This work saves lives, and much more.

Disaster Trends Across Space & Over Time

The risk of specific natural hazards varies widely from region to region. For example, floods tend to occur in low-lying areas near water. The Sahel region (the southern edge of the Sahara desert in Africa) is periodically plagued by droughts. Forest fires tend to occur (as you might guess) in forests. Earthquakes and volcanoes tend to occur near boundaries of tectonic plates. Many of the world’s earthquakes and volcanoes occur along the edge of the Pacific Ocean, along the boundaries of the Pacific Plate. This region is known as the Ring of Fire for its intense volcanic activity.

Map showing the ring of fire along the west coasts of North and South American and the east coast of Russia and China
Figure 8.1 The Ring of Fire: The Ring of Fire is a zone of many earthquakes and volcanoes.
Credit: USGS

Within the United States, some regions are more vulnerable to natural hazards than others. For example, Pennsylvania has a relatively low vulnerability, whereas Florida has a relatively high vulnerability. Pennsylvania gets a lot of hot weather in the summer, cold weather in the winter, and rainfall throughout, but while this all can be inconvenient or unpleasant, it is usually not dangerous. Florida, on the other hand, doesn't have to bundle up so much in the winter, but it does face frequent hurricanes.

Generally speaking, disasters are becoming less deadly but more costly. Fewer people are dying in disasters, but damages are costing more in dollars. Improved science and technology is a main reason that fewer lives are lost. We are now better at forecasting disasters, and our buildings and other structures can better withstand the physical impacts. This increases our resilience to hazards. Growth in population and the economy is a main reason that more money is lost. Simply put, society now has more of value that is exposed to hazards. Even though much of this is also more resistant to damage, the total dollar amount of damage has been increasing.

These trends can be seen in graphs available online from EM-DAT, the International Disaster Database. Using the Disaster Trends database, you can view the number of disasters, the number of people affected, and the dollars of damages from 1900 to 2014. Please adjust the settings to examine several graphs. You can see that deaths are declining while the number of people affected is increasing over time, mainly due to population growth. There is also an increase in the number of disasters reported, which can be caused by population growth, economic growth, or changes in reporting standards. It seems that natural disasters are getting more costly perhaps because people are building more expensive infrastructure in hazard-prone areas. 

Human Factors

The severity of a disaster depends on both the physical nature of the extreme event and the social nature of the human populations affected by the event. Here are some important human factors that tend to influence disaster severity. A core point here is that different people, even within the same region, have different vulnerability to natural hazards.

Wealth. Wealth is one of the most important human factors in vulnerability. Wealth affects vulnerability in several ways. The poor are less able to afford housing and other infrastructure that can withstand extreme events. They are less able to purchase resources needed for disaster response and are less likely to have insurance policies that can contribute. They are also less likely to have access to medical care. Because of these and other factors, when disaster strikes, the poor are far more likely than the rich to be injured or killed. But there are exceptions. For example, some coastal areas contain expensive beachside real estate populated mainly by the rich, leaving the rich more vulnerable to tsunamis, storm surges, and other coastal hazards. Also, the rich tend to lose more money from disasters, simply because they have more valuable property at stake. We've already seen one example of the role of wealth, in the comparison of Hurricane Katrina (wealthier area, fewer deaths, higher monetary damage) to Cyclone Nargis (poorer area, more deaths, less monetary damage).

Education. Education is another important factor in hazard impacts. With education, we can learn how to avoid or reduce many impacts. When populations are literate, then written messages can be used to spread word about hazards in general or about specific disasters. Even without literacy, it is possible to educate a population about hazards in order to help it reduce its vulnerability. When populations include professionals trained in hazards, then these people can help the populations with their hazards preparations and responses. We'll see one example of the role of education on the next page: research by scholars in the Penn State Geography Department being used to help coastal communities in the face of hurricane storm surges. Here is another example that will help clarify exactly what sort of education is important for natural disasters.

Reading Assignment: Knowledge Without Modern Education

Modern education, such as that found in university geography departments, can be very helpful in reducing the harm from natural disasters. But other knowledge can help, too. Here are two readings about the 2004 Indian Ocean Tsunami that vividly illustrate this point.

Tsunami folklore 'saved islanders' by Subir Bhaumik for BBC News discusses how ancient, isolated tribes on Indian Ocean islands drew on their oral traditions to survive the tsunami.

Did Animals Sense Tsunami Was Coming? by Maryann Mott for National Geographic News discusses evidence suggesting that non-human animals forecasted and avoided the tsunami.

One key insight here is that we should not assume that our approach to education is necessarily the best, or that other approaches cannot work, too. Another insight is that the insights that we gain from our experience observing and living in the world, and sharing this experience with others, can be every bit as useful as the insights that we gain from classroom or textbook instruction. Indeed, for this reason, many researchers in geography and other disciplines spend a lot of time engaged in fieldwork, i.e., research in relevant locations around the world instead of in libraries and universities.

Some background information about the 2004 Indian Ocean Tsunami

On December 26, 2004, a massive earthquake occurred underwater in the Indian Ocean. The earthquake’s magnitude was about 9.2, making it one of the most powerful earthquakes ever. The force sent massive waves out in all directions. When the waves reached coasts, they caused massive destruction, killing over 230,000 people, making the event one of the deadliest natural disasters ever

Credit: 747TakeMeAway747

Governance. The nature of both formal governments and informal governance in a population is another important factor. Governments can advance policies that reduce vulnerability. They can establish agencies tasked with reducing vulnerability, such as FEMA in the United States. They can support education and awareness efforts, as well as economic development to reduce poverty. Finally, they can foster social networks and empower individuals and communities to help themselves to prepare for and respond to hazards. Likewise, even without governments, communities can informally engage in many of these governance activities. Often the most vulnerable people are those who are politically marginalized because these people have less access to key resources and opportunities. One example of the role of government that we've seen already is the Myanmar government during Cyclone Nargis. This government is isolated from the international community and, thus, was not welcoming to international assistance in the aftermath of the cyclone. Compare that to Haiti after its 2010 earthquake. Haiti, like Myanmar, is a poor country, but it has positive and close relationships with the international community and thus readily welcomed international assistance in the aftermath of the earthquake. This assistance saved many lives and is helping Haiti rebuild.

Technology. The capabilities of the available technology can also play a large role in disasters. Technology can improve our ability to forecast extreme events, withstand the impacts of the events, and recover afterward. Technology is closely tied to wealth, education, and governance. Wealthier, more educated societies are more likely to have more advanced technology. A society's governance systems play a large role in how - and how effectively - the available technology is used in a disaster situation. One striking example of the role of technology is in the international response to the 2010 Haiti earthquake. On the next page, we'll learn about new Internet mapping technology such as Ushahidi that was used to help rescuers locate people in need. A lot of other technology was used in the response. For example, the U.S. Navy sent the USNS Comfort, a hospital ship, to treat the injured, and several helicopters to transport the injured to the ship. Helicopters were also used to distribute water. The helicopters were crucial because Port-au-Prince's port was damaged, as were many roads.

USNS Comfort Red Cross ship and a helicopter in Haiti.
Figure 8.2 Striking Example of the Role of Technology: A Coast Guard HH-60 helicopter brings injured Haitians from a landing zone in Killick at the Haitian coast guard base to the USNS Comfort for medical treatment.
Credit: Work found at Wikimedia Commons

Age. Children and the elderly tend to be more vulnerable. They have less physical strength to survive disasters and are often more susceptible to certain diseases. The elderly often also have declining vision and hearing. Children, especially young children, have less education. Finally, both children and the elderly have fewer financial resources and are frequently dependent on others for survival. In order for them to survive a disaster, it is necessary for both them and their caretakers to stay alive and stay together. An example of the role of age is the 2003 European heat wave. About 40,000 people died in one of the hottest summers ever in Europe. Many of the deaths were elderly people who were still capable of taking care of themselves. These people were not able to adapt to the extreme heat and had no one helping them out.

Gender. Women are often more vulnerable to natural hazards than men. This is in part because women are more likely to be poor, less educated, and politically marginalized, often due to sexism in societies around the world. Women often face additional burdens as caretakers of families. When disaster strikes, women are often the ones tasked with protecting children and the elderly. This leaves them less mobile and more likely to experience harm themselves.

Are there other human actors that influence disaster severity? Can these factors be integrated to disaster preparedness so that people can be better prepared and have faster and more efficient response to disasters?