In Harm's Way: Hurricanes, Population Trends and Environmental Change

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In Harm's Way: Hurricanes, Population Trends and Environmental Change

Research paper

By: Roger-Mark De Souza

Date: October 2004

Source: De Souza, Roger-Mark. "In Harm's Way: Hurricanes, Population Trends and Environmental Change." October 2004. 〈〉 (accessed January 6, 2006).

About the Author: Roger-Mark De Souza is Technical Director at the Population Reference Bureau (PRB) in Washington, D.C. He holds a Master of Arts degree from the George Washington University and a postgraduate degree in International Relations from the University of West Indies. At the PRB, De Sousa conducts research on a wide range of development policy issues. He also provides technical support on health, environment, development, and related issues to countries in the Caribbean region.


Hurricanes are a constant natural threat in the United States and the Caribbean regions. Between 1991 and 1999, nearly fourteen hurricanes struck coastal areas in the United States. Five of these were major. In fact, the United States is hit by a category four or stronger hurricane around once every six years. In 2005, Hurricane Katrina completely devastated the city of New Orleans. More than a million people were displaced as a direct consequence of this disaster.

Besides being huge environmental hazards, hurricanes cause great economical damage to regions they hit. Human population becomes vulnerable in more than one way to such environmental disasters. Hurricanes leave entire populations susceptible to several economic and social consequences.

Population trends in hurricane-affected regions also keep changing. Since the late twentieth century, coastal regions affected by hurricanes have seen a marked increase in population. The ability of populations to rebuild themselves after tropical storms significantly depends upon the regional or the national economy. Often, smaller island nations find themselves economically handicapped to rebuild hurricane-damaged regions.

Factors such as an increase in migration from rural to urban areas also influence a region's ability to recover from the economic impact of hurricanes. Hurricane activity has also been increasing over the years. Less-understood factors such as climate change and an increase in greenhouse gases tend to contribute to increased hurricane activity.

Before rural-to-urban migration became a trend, and later a social economical need, natural disasters like hurricanes were a lesser threat to human population and economy.

De Souza's paper describes growing population trends and the threats faced in relation to the increased risk from hurricanes caused by global climate change. Factors like population and urbanization of previously uninhabited lands have increased the severity of economic damages faced in the aftermath of hurricanes. This trend is more visible in the case of island countries in the Caribbean that are primarily dependent on tourism for their sustenance.

Dictated by economic needs, the last few decades have seen an increasing trend in the urbanization of these areas. Hurricanes affect both affluent and poor populations from developed and developing countries. In the United States, a significant number of people keep migrating to warm coastal areas such as Florida and California. Federal studies have revealed that less affluent people generally tend to stay in marginally developed areas such as coastlines, riverbanks, and low-lying areas. People residing or living in these areas can be more vulnerable to natural disasters. The economic void created in the aftermath of such disasters creates a myriad of problems for administrators and governments alike.



In September 2004, four devastating hurricanes and tropical storms killed more than 1,500 Haitians, destroyed roughly 90 percent of Grenada, and wreaked billions of dollars of damage on the southern United States.

But such calamities from extreme weather are hardly an accident of nature. Instead, these tragedies highlight when and how environmental hazards combine with socioeconomic conditions—particularly population and environmental trends—to magnify the threat of disaster for tens of millions of people in both the developed and the developing world.

The Factors That Increase Vulnerability to Hurricanes Hurricanes and tropical storms have always been one of the primary causes of natural disasters in the Caribbean and the coastal southern United States. But the economic impact of hurricanes in these areas is growing far more severe.

The insurance industry in the United States has paid out more than $39 billion since 2000 to cover hurricanes and other natural disasters—a figure more than half the total of all catastrophic event payments made by the industry in the preceding 30 years.

This rise in insurance costs reflects not just greater hurricane activity, but people's increased vulnerability to those storms due to three factors: population pressures, the effects of poverty and affluence, and other environmental changes that exacerbate a hurricane's strength and effects.

Vulnerable Locations and Population Pressures To some extent, human vulnerability to natural disaster is a geographical misfortune. For example, because of their fragile environments and economies, islands are highly vulnerable to devastating hydrometeorological and geological disasters. According to the United Nations Conference on Trade and Development, 13 of the 25 countries that suffered the greatest number of natural disasters during the 1970s and 1980s were small island states.

But accelerating numbers of people are choosing to live in areas that are at increasing risk for natural devastation. For example, approximately 13 million Floridians now live in coastal counties, up from 200,000 a century ago. And more people live in South Florida's Dade and Broward counties now than lived in the entire southeastern United States in 1930.

Aggressive coastal development, especially the building of homes and businesses in these fragile areas, is also increasing human vulnerability to natural disasters.

A 2000 study commissioned by the Federal Emergency Management Agency found that Americans have built more than 350,000 structures within 500 feet of U.S. coasts. The study also warned that coastal erosion could claim one in four of those buildings within the next 60 years.

Caribbean countries are equally vulnerable to tropical storms. Major population centers, agricultural areas, ports, and centers of industrial and commercial activity are mostly located in the coastal zone. And tourism—a mainstay of many Caribbean economies—is also largely concentrated in coastal areas.

The vulnerability of these urban coasts is exacerbated by population growth. While fertility rates have fallen nearly everywhere in the developing world, population in the Caribbean will continue to grow as large numbers of young people move into their reproductive years.

On average, roughly one-third of people in the Caribbean are under age 15. (Haiti has the most youthful population in the region, with 43 percent of its population under age 15.) This population growth is particularly acute among the poor, who have traditionally had the least capacity to exercise their reproductive preferences.

Rural-to-urban migration and increasing urbanization has also aggravated the impact of natural disasters among developing countries in the Caribbean. Indeed, the Caribbean is the most urbanized island region in the world, with an urban population that grew an average of 1.58 percent annually from 1995 to 2000. Several islands—such as the Bahamas, Cuba, Dominica, Puerto Rico, and Trinidad and Tobago—are already predominantly urban.

The trend towards urbanization provides additional pressures on the environment and increases vulnerability to natural hazards, particularly among the poor. The urban poor tend to live in informal settlements, and their housing is often inadequately constructed.

Large urban areas such as Kingston in Jamaica and San Juan in Puerto Rico tend to be more hazardous locations than sparsely populated rural areas because of their population size and the potential scale of damage. In these urban areas, impervious surfaces such as roads and buildings generate more runoff than forested land. And fixed drainage channels may be unable to contain runoff from intense rains.

Poverty and Affluence Poverty is a central component of vulnerability to tropical storms: Developing countries contain 90 percent of the victims from natural disasters and bear 75 percent of their economic damages.

The World Bank estimates that 80 percent of the poor in Latin America, 60 percent of the poor in Asia, and 50 percent of the poor in Africa live on marginal lands characterized by poor productivity and high vulnerability to natural degradation and natural disasters.

Where the poor live in the developing world contributes enormously to their vulnerability to tropical storms and their aftermath. These people often have no choice but to occupy the least-valued plots of land in disasterprone areas such as riverbanks, unstable hillsides, deforested lands, or fragile water-catchment areas.

These patterns predetermine not only the poor's susceptibility to natural disasters, but also their capacity to cope with their aftermath. Poorer families may be forced into increased debt in order to rebuild their homes, replace assets, and meet basic needs until they are able to recommence income-generating activities.

More affluent societies and individuals also have put themselves at increased risk for natural disasters such as hurricanes, although they have more resources with which to brace for and handle the aftermath of such events.

As noted above, disaster-prone areas of the United States are being settled by people with higher-than-average incomes—often to find jobs, to be near to recreation possibilities, or to build secondary homes. In some cases, economic incentives for responsible land use have been curtailed by legislated insurance rates and federal aid programs that effectively subsidize development in hazard-prone areas.

Environmental Changes Environmental degradation also increases vulnerability to tropical storms. Serious coral bleaching and mangrove loss, for example, make coastlines more susceptible to flooding. Similarly, deforestation contributes to droughts, flash floods, and landslides. For example, rains from Tropical Storm Jeanne pounded land in Haiti that had been cleared for charcoal production, ultimately leading to the death of more than 1,000 people. By contrast, greater land cover buffered the coastline of the Dominican Republic (which shares the island of Hispatola with Haiti) against widespread flooding from Jeanne as well as subsequent landslides—resulting in significantly less deaths.

Global warming could also contribute to a rise in the number and the intensity of hurricanes that will hit the Caribbean and the southern United States, although scientists are still debating the precise impact of such warming.

Recent research suggests that, by 2080, seas warmed by rising atmospheric concentrations of heat-trapping greenhouse gases could cause a typical hurricane to intensify about an extra half-step on the five-step scale of destructive power. Rainfall up to 60 miles from the storm's core would also be nearly 20 percent more intense.

Moving Out of Harm's Way Reducing vulnerability to hurricanes in the Caribbean and the southern United States must include an understanding of how population trends and environmental changes interact with geographic predisposition to natural hazards, policy choices, and economic drivers of change.

The upcoming World Conference on Disaster Reduction (WCDR) in Japan (in January 2005) will be an opportunity for world leaders to recognize these important linkages. In preparation for the conference, the International Strategy for Disaster Reduction (ISDR) Secretariat and the United Nations Development Program have developed five focus areas for understanding, guiding and monitoring disaster risk reduction at all levels. These areas are: governance, risk identification, knowledge management, risk-management applications, and preparedness and emergency management.


Population trends worldwide are significant indicators of economic hardships faced, especially in times of distress and disaster. Growing population trends in areas that face natural disaster mean increased consequential economical risk from natural disasters. Factors like climate change can compound the risks faced by populations migrating to or residing in these regions.

According to environmental groups, the growing population trend in hurricane probable zones is a matter of great concern. A World Bank study noted that nearly 90 percent of the world's poor stay in marginalized areas that can become the most affected zones in event of natural disasters like hurricanes. Another study by the same organization showed that an immense amount of funds could be saved if governments invest appropriate sums in planning for disaster preparation and alleviation.

In his paper, De Souza examines how populations of countries in the Caribbean region and the United States are being increasingly exposed to hurricanes brought about by environmental change. He argues that hurricanes not only affect people in the developing world, but populations in the developed world as well. He further discusses that smaller island countries can be more susceptible to damage caused by hurricanes. The devastation caused thereby is not entirely an environmental accident, but can be linked to the socioeconomic factors affecting the populations of that region.

Furthermore, the economical damage caused by hurricanes is far greater than the geographical damage they cause. He notes it has cost the insurance industry more than $39 billion since 2000 to cover hurricane damage in the United States.

De Souza states that although it is not possible to completely escape the disastrous aftermath of hurricanes, it is possible to mitigate the harm they can cause. Changing population trends need not necessarily mean more economic damage and harm if hurricane affected nations include prudent safety and rehabilitation measures in every disaster plan.

For this purpose, De Souza outlines a number of recommendations in his paper. These include understanding deforestation and global warming, encouraging reforestation, implementing measures that reduce harmful emissions, developing conventional disaster plans that include contingency measures, and allocating surplus funds in the wake of hurricanes.

Amongst other measures, De Souza states that long-term resettlement plans should be drawn up for people living in commonly hurricane-affected areas, so that future hurricanes do not cause massive economic damage. These steps could go a long way in identifying the need for assistance in the right areas where, for example, aid from crucial areas like foreign governments and agencies could be channeled and integrated with regional and local funding plans. As natural hazards can pose a serious hindrance to sustainable development, this aspect should be considered by various governments in all areas of economic planning.


Web sites

Benson, Charlotte. "The Cost of Disasters." Benfield Hazard Research Centre. 〈〉 (accessed March 17, 2006).

Jarrell, Jerry D., Max Mayfield, Edward N. Rappaport, and Christopher W. Landsea. "The Deadliest, Costliest, and Most Intense United States Hurricanes from 1900 to 2000." Atlantic Oceanographic and Meteorological Laboratory, updated October 2001. 〈〉 (accessed March 17, 2006).

Lynas, Mark. "Warning in the Winds.", September 19, 2004. 〈〉 (accessed March 17, 2006).