Coastal regions, areas that are home to a large and growing proportion of the world’s population, are undergoing environmental decline. The problem is particularly acute in developing countries. The reasons for environmental decline are complex, but population factors play a significant role. Today, approximately 3 billion people — about half of the world’s population — live within 200 kilometers of a coastline. By 2025, that figure is likely to double. The high concentration of people in coastal regions has produced many economic benefits, including improved transportation links, industrial and urban development, revenue from tourism, and food production. But the combined effects of booming population growth and economic and technological development are threatening the ecosystems that provide these economic benefits. Unless governments and users of coastal resources take action, population pressures and the associated levels of economic activity will further degrade many coastal habitats.

The challenge for policymakers and coastal resource managers is to figure out how to reap the economic benefits of coastal resources while preserving them for future generations. Addressing population issues is key to achieving such balance. This policy brief looks at how population growth, urbanization, and other factors affect coastal resources; how environmental degradation influences people’s lives; and how policymakers can integrate population and resource management issues.

Coastal Regions: Benefits and Challenges

Because there is no common definition of what constitutes a coastal region, estimates of coastal populations vary. Most are based on an area within 60 to 200 kilometers of the shoreline and may include coastal floodplains, coastal forests called mangroves, marshes, and tideflats (coastal areas affected by the rise and fall of the tide), as well as beaches, dunes, and coral reefs.1 The term “coastal regions” also covers marine fisheries because the bulk of the world’s marine fish harvest is caught or reared in coastal waters.2 Coastal areas help prevent erosion; filter pollutants; and provide food, shelter, breeding areas, and nursery grounds for a wide variety of organisms. Coastal regions also provide critical inputs for industry, including water and space for shipping and ports; opportunities for recreational activities such as fishing and diving; and other raw materials, including salt and sand.

In many countries, populations in coastal areas are growing faster than those in noncoastal areas. This is a concern because population growth and the activities associated with it can degrade coastal and marine ecosystems.3 A number of worrying trends are already visible. In some areas, heavy use of fisheries has reduced endemic coastal fish stocks to 10 percent to 30 percent of the supply that existed 30 years ago.4 Half of the world’s wetlands disappeared in the 20th century, as did 50 percent of all mangroves, and nearly 60 percent of the world’s coral reefs are seriously degraded — in some cases beyond recovery — or threatened by development and other human activities.5 Pollution from industry, agriculture, and urban areas is degrading the quality of much of the world’s fresh water. These challenges are particularly acute for island countries, where coasts often comprise the entire territory.6 Such countries may also be threatened by rising sea levels, a possible consequence of climate change.

Population Factors’ Effects on Coastal Regions

Changes in the size, composition, and distribution of human populations affect coastal regions by changing land use and land cover. Fishing or harvesting, the destruction of mangroves, and pollution and sedimentation from human activities all can affect the coastal environment.

Population Density

The average population density in coastal areas is about 80 persons per square kilometer, twice the world’s average population density.7 Up to 50 percent of the population in northern Africa and Bangladesh lives in coastal areas; along the Nile Delta, the population density reaches 500 to 1,000 people per square kilometer.8 The additional demands that high population density places on the coasts have meant that higher density is associated with increased risks to marine ecosystems. But higher population densities may have beneficial effects as well: As population grows, some governments make greater investments in infrastructure such as sewer lines and sewage treatment plants that ultimately reduce levels of environmental contamination.


Migration is a key factor affecting coastal zones. The figures in China and Southeast Asia are staggering: 1,000 people arrive in China’s large coastal cities each day, and similar numbers move to the coasts in Vietnam and the Philippines. The population of Ecuador’s Galapagos Islands has grown rapidly since the early 1980s, largely due to the arrival of coastal fishermen. These fishermen sometimes unknowingly exacerbate a problem created by tankers and ocean liners. By discharging ballast water near the islands, large vessels and smaller fishing boats have introduced nonindigenous plant and animal species to the islands’ coasts.9 The situation in the Galapagos Islands also highlights how migration can contribute to the depletion of natural resources. The arrival of new fishermen, together with the introduction of new fishing techniques and increased access to credit and markets, has contributed to the overexploitation of sea cucumbers in the region.10


Many of the world’s coasts are becoming increasingly urban. In fact, 14 of the world’s 17 largest cities are located along coasts. Eleven of these cities, including Bangkok, Jakarta, and Shanghai, are in Asia. In addition, two-fifths of cities with populations of 1 million to 10 million people are located near coastlines.11 The urbanization of coasts brings with it coastal development (including demands for fresh water and sewage treatment) and damage to coastal ecosystems.

Urbanization has a deleterious effect on mangroves. Mangroves, forests of salt-tolerant trees and shrubs that grow in the shallow tidal waters of estuaries and coastal areas in tropical regions, line about 8 percent of the world’s coastlines and 25 percent of the world’s tropical coastlines, where they absorb the impact of storms and offer nutrients for most of the world’s marine life.12 A study by the U.S.-based World Resources Institute found that mangrove loss was strongly correlated with the growth of cities and ports.13 Mangrove forests are also cleared for timber and to make room for fish and shrimp ponds, human settlements, and agricultural and industrial development. Kenya, Liberia, the Philippines, and Puerto Rico, have lost over 70 percent of their mangroves.14

Population’s Interaction With Other Factors

Nondemographic factors, including the economy, national and local policies, technology, and culture, interact with population changes to affect the natural environment. Tourism, fishing, and aquaculture are industries with major economic influences on coastal ecosystems.


Coastal areas worldwide are major destinations for tourism, which represents the fastest growing sector of the global economy.15 Tourism dominates the economy of some regions and small island states; for example, tourism constitutes 95 percent of the economy of the Maldives and is the country’s only source of hard currency.16 Tourism can offer some environmental benefits, such as greater appreciation of the value of natural resources. In the Caribbean, for instance, diving tourism has helped raise awareness about the need for reef conservation. But tourism can also have harmful effects (see Box 1). It can lead to unsustainable coastal development as infrastructure is built on the shoreline to accommodate tourists. In the Caribbean, official estimates say that 70,000 tons of waste are generated annually from tourism activities.17 Yachts, charter boats, and cruise ships are major sources; they bring visitors to ports that often have inadequate collection systems for dealing with the solid waste discharged by the ships. Moreover, the ships provide few long-term economic benefits for the local population, since they do not employ many local citizens.

Fishing and Aquaculture

Marine fisheries and aquaculture (the controlled cultivation and harvesting of freshwater and marine organisms) produce close to 100 million tons of fish, shellfish, and edible plants every year, providing a livelihood for about 35 million people, most of whom live in developing countries.18 Overharvesting to meet global consumers’ growing demand for seafood can deplete many species and alter the biological structure of coastal ecosystems. Many species are overharvested because the world fishing fleet is larger than it needs to be. Other problems include destructive harvesting methods such as trawling (dragging weighted nets across the sea floor to catch shrimp and bottom-dwelling fish), and bycatch (unintended catch of nontarget species).19 Modern trawling equipment scoops through sediment and rock and often kills the worms, sponges, and other species that live on the seafloor. Aquaculture, the world’s fastest growing food production activity, with an annual growth rate of about 10 percent in the 1990s, can lead to the destruction of mangroves and may lead to irreversible damage to both estuarine and offshore fisheries by introducing biological, chemical, and organic pollutants (such as antibiotics and pesticides) and by modifying habitats.20

Human Health, Food Security, and Gender Issues

People who live in coastal regions may suffer the cumulative burden of environmental stress from the activities on and overcrowding of the coast and from upstream and inland development. If not properly managed, development can result in pollution, deforestation, and inadequate management of soil, water, pesticides, and fertilizers. Damming rivers can also have negative environmental effects, such as soil erosion and destruction of ecosystems that support various fish and marine mammals. When concentrated in small, confined, and overcrowded areas such as coastal zones, pollution and other problems pose greater threats to human health.

Worldwide, sewage is the largest source of environmental contamination, and discharges have increased dramatically in the past three decades. Eighty percent of marine pollution comes from land-based sources; the remaining 20 percent comes from atmospheric sources, including acid rain and marine-based sources such as oil spills.21 As coastal communities grow, sewage can become a threat to local waterways: Demand often exceeds available sewage treatment, and much of the sewage is dumped without being treated. Bathing in or ingesting sewage-contaminated water can cause infections and transmit diseases such as cholera, particularly among children under 5.22 In developing countries, more than 90 percent of wastewater and 70 percent of industrial wastes are discharged in coastal waters without being treated. The United Nations Environment Programme estimates that South Asian waters are at the highest risk of pollution: 825 million people in the region do not have basic sanitation services.23 In Mumbai, India, for instance, almost half of the city’s 12 million residents are either slum dwellers or homeless with little access to sewage and sanitation facilities. The Municipal Corporation of Brihan Mumbai, with support from the World Bank, has started the $300 million Bombay Sewage Disposal Project to collect and dispose of 80 percent of the sewage currently flowing untreated into the sea.24

Chemicals and heavy metals found in pesticide runoff and industrial effluents also damage human and marine health. The most serious concerns worldwide involve persistent organic pollutants (POPs), which can be transported in the atmosphere and have become common in the oceans. POPs tend to linger in living tissue and become more concentrated as they move up the food chain, so they are sometimes found even in people who live in remote, undeveloped regions. Evidence links long-term, low-level exposure to certain POPs with reproductive, immunological, neurological, and other problems in marine organisms and humans.25 In Mozambique, for example, more than 100 factories in and around the capital city of Maputo do not have waste treatment plants; toxic wastes, poisons, nondegradable substances, and organic matter are drained into coastal waters.26 These toxins can kill or contaminate marine life; people who eat seafood from polluted areas or who swim in contaminated waters are vulnerable to gastric and other infections.

Contaminants and activities that destroy coastal habitats and ecosystems also contribute to the loss of the marine fauna on which many people rely for food and income. Maintaining a healthy coastal habitat is critical because most of the world’s fish produce their young inshore and feed on organisms in coastal waters. Breaking the marine food chain reduces vital supplies of protein for about 1 billion people, most of whom live in developing countries.27

Yet restricting fishing rights and access to coastal waters in order to project marine fauna may harm vulnerable groups of people. Poor women depend especially heavily on fish and fishing. They tend to fish close to the shore and use the catch to feed their families, whereas men typically engage in large-scale commercial fishing offshore or in major inland water bodies.28 Operating on a smaller scale, women who fish earn only 40 percent of what men earn for fishing in El Salvador. The situation is similar in rural Honduras, where women earn about half of what men do.29

Being less visible in their work, women are also less likely to have access to decisionmakers or to be consulted about the management of natural resources. In the early 1990s, community leaders in El Salvador informally banned fishing in estuaries due to concerns about the overfishing of shrimp and other sea life in the estuary. Women were not consulted in this process and lost a vital source of household protein and income.30 Women usually have different access to and control over land and water in coastal zones: Fewer than 5 percent of beneficiaries of land reform in El Salvador and Honduras were women.31

Integrated Coastal Management

Managing population pressures in coastal zones is difficult because those regions encompass many physical, social, and regulatory divisions. In addition, multiple competing economic sectors, including tourism, fishing, agriculture, aquaculture, forestry, manufacturing, oil and gas extraction, waste disposal, marine transportation, and real estate development have interests in coastal zones. Governments usually manage each sector separately, if at all. Consequently, many coastal nations have experienced rapid uncontrolled development along their coastlines.

In a growing number of countries, coastal zone managers are adopting integrated, multidisciplinary approaches to resource management that incorporate the perspectives of all stakeholders, including governments, the private sector, nongovernmental organizations (NGOs), and individuals. Integrated coastal management (ICM), an internationally accepted approach to managing resources that is based on the United States’ 1972 Coastal Zone Management Act, allows policymakers and planners to take population issues into account when looking at the pressures, threats, and opportunities facing coastal areas. ICM has been endorsed repeatedly in international conferences, including the 1992 UN Conference on Environment and Development in Rio de Janeiro, Brazil, and the 2002 World Summit on Sustainable Development in Johannesburg, South Africa.

ICM attempts to forge a balance between users of water and natural resources while ensuring that long-term environmental health and productivity are not compromised.32 Countries may use ICM to address the depletion of coastal and ocean resources; deal with pollution that endangers public health; distribute the economic benefits of using the coast and ocean; or develop and manage coastal and marine areas that are not yet being exploited.

At least 107 of the world’s 134 coastal developing nations are involved in some type of ICM effort at the national or subnational level.33 In general, the most successful ICM efforts share several characteristics:

  • Multiple stakeholders, including representatives from all levels of government, NGOs, indigenous groups, communities, and the private sector;
  • A strong scientific foundation to inform the management process;
  • A formalized mandate and funding mechanisms;
  • Formal decisionmaking that incorporates social, environmental, and economic data;
  • Public participation starting at the initial stages of policy formulation and program development;
  • Community-based management initiatives to develop community experience, build support, and provide information about regional or national programs;
  • Capacity building of local experts through training, education, and applied research;
  • Strong outreach services that provide information and education to all levels of management; and
  • Regular collection of reliable data to measure the success of management initiatives.34

Future Steps in Addressing Population Issues in Coastal Regions

Managing coastal areas requires concerted multisectoral efforts by government institutions at all levels, the private sector, and community groups, as well as sustained political support. Achieving a balance between top-down legislative authorities and bottom-up community involvement requires understanding issues and maintaining strong links with stakeholders in the area.

Efforts to balance local interests with national legislation need to consider the socioeconomic context of coastal populations and what role demographic patterns play in the region. Policymakers and program managers can take several steps to address and integrate population concerns into their coastal management efforts.

Include Population Data in Baseline Studies on Coastal and Marine Resources

Baseline studies assessing the threats to coastal areas should include data on population and the environment, indigenous peoples’ concerns, applicable legislation and the agencies involved, gender concerns, and socioeconomic characteristics of the areas. These studies can be conducted using either exhaustive research or rapid assessment techniques. Data can then be applied with simple participatory tools to quickly assess coastal and marine resources and identify critical threats, such as the extent of fishing and any destructive fishing practices (see Box 2).

Incorporate Population and Gender Dynamics Into Planning

Coastal resource managers and policymakers need to integrate health, population, gender, and nutrition considerations into ICM by determining the characteristics of beneficiaries and stakeholders, NGO capacity, and opportunities in specific areas. For example, women in coastal areas may have unmet need for family planning — that is, they may want to limit or space their future births but may not be using contraceptives.35 Helping women reach their family planning goals can protect the environment by limiting population growth, but addressing family planning needs must be coordinated with several sectors, particularly the health sector.

Several strategies can be used to incorporate population and gender dynamics in planning project activities:

  • Staggered introduction. A program is established in one sector, and another program in a different sector is later incorporated into the first activity.
  • Simultaneous introduction. A number of programs are introduced at the same time, and stakeholders consider multiple issues at each stage.
  • Bridge approach. Single-sector activities support one another but are conducted by different staff.
  • Symbiotic method. Program activities are dependent on one another and are conducted by the same staff.36

In the Philippines, for example, projects have used a combination of these models to build links across sectors. ICM projects developed out of separate single-sector programs, such as those introducing ecologically sound fishing practices and improving the quality and availability of couples counseling on family planning, and later evolved into integrated programs in which project staff worked with local communities and external experts to coordinate integrated population, health, and environment programs (see Box 2).

Monitor and Assess Human Impacts on the Marine Environment

Integrated management of the marine environment and its natural resources requires greater emphasis on acquiring, analyzing, and using environmental data from a variety of disciplines. It also involves improving the exchange of data between the science and management communities and focusing more on demographic and socioeconomic factors that contribute to marine pollution and coastal degradation.

Population estimates for coastal watersheds could provide useful information for coastal managers, especially if the data describe population dynamics on a larger scale. In the United States, the National Oceanographic and Atmospheric Administration has developed the Coastal Assessment Framework, which uses census data and mapping programs to provide managers and analysts with a watershed-based system for collecting and organizing resource-use data and developing coastal management strategies.37 Many problems with water quality and ecosystems are best solved at the watershed level, which encompasses the full area that drains into a particular body of water.

The Caribbean Coastal Marine Productivity Programme (CARICOMP), a regional network of marine laboratories, parks, and reserves that studies land-sea interactions, strives to identify which changes in coastal systems are caused by human disturbances and which are simply long-term natural variations. The program focuses on understanding the structure and function of mangroves, seagrasses, and coral reefs, the primary coastal ecosystems in the Caribbean. CARICOMP is one example of a functioning international program for monitoring the coastal marine environment and can be used as a model for other countries or regions.38


Demographic factors, especially migration, are major considerations in how people use coastal regions. Understanding how population issues can be integrated into coastal management will help policymakers, program managers, and communities design more viable and sustainable strategies for using and safeguarding the world’s coasts and the resources they provide.

Liz Creel is senior policy analyst at PRB.


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  35. Joan Castro et al., “Integrating Population and Coastal Resource Management for Food Security — The Philippines’ Model” (2000), accessed online at, on June 20, 2003.
  36. Rainera L. Luero and Robert Layng, “Understanding Reproductive Health/Natural Resource Management Integration in the Philippines,” World Neighbors 28, no. 2 (2002).
  37. NOAA Office of Ocean Resources Conservation and Assessment (ORCA), “ORCA’s Coastal Assessment Framework,” accessed online at, on June 30, 2003.
  38. Bjorn Kjerfve et al., “CARICOMP: A Caribbean Network of Marine Laboratories, Parks, and Reserves for Coastal Monitoring and Scientific Collaboration” (May 1998), accessed online at
    csi/pub/papers/kjerfve.htm, on June 20, 2003.


Liz Creel prepared this policy brief with assistance from PRB staff and other colleagues. Thanks are due to Lori Ashford, Patricia Biermayr-Jenzano, Roger-Mark De Souza, John Williams, and Nancy Yinger, PRB; Pam Rubinoff and Elin Torell, the Coastal Resources Center of the University of Rhode Island’s School of Oceanography; Don Hinrichsen, author and UN consultant; Marea Hatziolos, the World Bank; Alfred Nakatsuma and Tom Gardiner-Outlaw, U.S. Agency for International Development; Richard Langton, Buccoo Reef Trust; Naida Pasion, Save the Children/Philippines; and Salif Diop, Patrick M’mayi, and Philippe Rekacewicz of the United Nations Environment Programme.

This work has been funded by the U.S. Agency for International Development (USAID) under the MEASURE Communication project (HRN-A-00-98-000001-00). PRB’s work with Save the Children in the Philippines, highlighted in this brief, has been supported by the David and Lucile Packard Foundation.

Box 1
Buccoo Reef, Tobago: Balancing Tourism, Health, and Livelihood