Part 2: Issues in Sustainable Development

To the Instructor

This issue block includes a large amount of material from the disciplines of environmental science and ecology. Depending on how familiar students are with the stylized facts of ecosystem degradation and biodiversity loss, more or less time may be spent on the Assignment Questions and graphic materials versus the Discussion Questions.


This first issue sets the tone for the Block. The foundation of all life and resulting human well-being is derived from the richness of biological diversity that is present, thus the objective  of this issue is students’ appreciation of the value of the world’s rich assortment of life. The Core Readings provide a basic orientation to biodiversity especially for students with little previous exposure to the subject. Assignment Question number 2 checks for student comprehension of the various ways biodiversity supports human well-being.

Biodiversity Assignment Questions

  1. Biodiversity: Define biodiversity. What are some major threats to biodiversity worldwide?

    • (from Species Loss…) “Biodiversity is the variety of plants and animals present in the natural environment.”
    • (from AEO 2) Biodiversity “refers to the abundance and variety of living things, and can be considered at several levels: the genetic variation within a population, the number and relative abundance of species, and the variety of ecosystems.”
    •  (from Species Loss…) Major threats: habitat destruction, invasive species, global warming. Also, from other readings, overharvesting of natural resources.
  2. Biodiversity: Explain the link between ecosystem services and biodiversity. Give some examples of ecosystems services in Africa.

    • (from AEO 2) Some level of biodiversity is necessary for the healthy functioning of ecosystems, which in turn provides valuable ecosystem services. Plants and animals from natural ecosystems are used in traditional and modern pharmaceutical products. Healthy river ecosystems provide pollution detoxification, while terrestrial ecosystems play complex roles in climate regulation. Recreational use of natural areas and nature-based tourism are also benefits of biodiversity.

  3. Biodiversity: Setting aside protected areas is the most common policy for preserving biodiversity. How should protected areas be designated?

    • (from AEO 2) Protected areas should not be chosen arbitrarily, but should be designed to provide enough habitat for preserving the maximum amount of biodiversity. Because there is a lack of good data on biodiversity, improving science is an important first step.

  4. Biodiversity: Find and explain an example in the readings of biodiversity preservation other than setting aside protected areas.

    • (from AEO 2) Among possible examples: commercialization of pharmaceuticals derived from native plants, grazing livestock in natural areas, and planting a variety of crop species rather than relying on mono-culture.

Oceans and Seas

Many students may not have much personal familiarity with saltwater environments. However, oceans and seas affect their lives at macro and micro scales. Oceans are a main driver of weather patterns, climate, and temperature as well as a significant source of protein in the diet of many Africans. Since coastal areas frequently have high population levels, people have tremendous impact on the health and productivity of coastal waters. Since relatively few people have personal contact with these waters, damage to them goes largely unseen. It is critical that students understand how to protect and conserve these largely “invisible” ecosystems.

Oceans and Seas Assignment Questions

  1. Oceans and Seas: Summarize the definition of an ecosystem from the UN Ocean Atlas readings. Why is it important to understand the operation of ecosystems in their entirety, rather than just studying individual species?

    • (from “Ecosystems”) An ecosystem is “a functional unit comprising all the organisms in a particular place interacting with one another and with their environment, and interconnected by an ongoing flow of energy and a cycling of materials.” An ecosystem, as a “functional unit,” needs to be studied as a whole. Its productivity depends on interactions between the various species in the ecosystem and the physical environment. This is important because human actions that harm the physical environment and reduce biodiversity can eventually seriously harm ecosystem function. Fully understanding these effects is a major challenge for biologists.

  2. Oceans and Seas: Discuss the ecological importance of mangrove forests and coral reefs. What particular human activities threaten these coastal ecosystems?

    • (from In the Front Line) Mangrove forests and coral reefs both provide regulating services, such as shoreline protection, although scientists do not yet understand the exact mechanism of this protection. Reefs and mangroves also both contribute to the populations of commercial fish species, with mangrove forests important as breeding and nursery areas for many fish species. Other services include tourism (reefs), carbon sequestration (mangrove forests), high quality timber (mangrove forests), and water filtration to remove heavy metals (mangrove forests). Mangroves forests are particularly threatened by clearing for aquaculture, salt production, and coastal development, while coral reefs are threatened by illegal commercial fishing techniques using dragnets and explosives as well as by coral bleaching which occurs as ocean temperatures rise. Both coral reefs and mangroves are threatened by natural disasters and by sedimentation, a land-based pollution that decreases the ability of light to penetrate the water.

  3. Oceans and Seas: Choose one of the management tools explained in In the Frontline. How does this tool reflect an ecosystem approach to environmental management?

    • (from In the Front Line) Marine Protected Areas reflect an ecosystem approach because the justification for conservation is based on an understanding of the value of ecosystem services. Annual operating costs of $775 per sq km are far less than the estimated value of ecosystem services. As with land-based protected areas, they should ideally be designated to ensure that connected ecosystems are protected, because some species depend on different ecosystems at different stages in their lives.
    • Integrated Coastal Management (ICM) includes implementing best practices related to construction and development, such as silt curtains to control sedimentation. ICM reflects an ecosystem approach because it is based on an understanding of how sedimentation and other types of habitat degradation affect ecosystem stability, leading eventually to a decline in ecosystem services.
    • Improved Resilience and Adaptive Management is related to preventing damage from natural disasters and reflects an ecosystems approach in that it calls for greater understanding of the factors that create ecosystem resiliency.


Forest loss is a major problem in Africa. Most people are unaware or underestimate the value of the forests for traditional food, sequestration of carbon, medicinal products, habitat, and erosion control. Forests have been referred to as the “lungs of the planet” for their ability to take in carbon dioxide and produce oxygen. These topics as well as the better-known value of forests as a source for timber and wood products are presented in this module. With this expanded appreciation of forests, students should become interested in more responsible forest resource management.

Out of classroom activities to consider are visits to a forest or a Geographical Information System (GIS) laboratory so students can observe change in forest cover, forest health, and forest resources in person or through mapping technology.

Forests Assignment Questions

  1. Forests: How severe is the rate of deforestation of tropical rainforests, and which regions are most affected? Why are environmental scientists concerned about rainforest loss?

    • (from GEO-4 “Forests”) Rainforests are being destroyed at a rate of approximately 0.2% per year between 1990 and 2005 during which losses were greatest in Africa and Latin America and the Caribbean. All forests provide a wide range of ecosystem services. One of the most important services is the moderation of climate change by fixing carbon from the atmosphere as biomass and soil organic carbon. The decline in total forest area combined with continued forest degradation has resulted in a decline in forest carbon fixation that is greater than the rate of decline in forest area.

  2. Forests: List as many ecosystem services of African forests as possible. Include regulating, provisioning, and cultural services.

    • (from AEO 2) Regulating: carbon sinks, preventing soil erosion, maintaining river flow. Provisioning: wood for timber and energy, bush meat, edible plants, roots, mushrooms, medicinal plants, gums, resins, honey, and beeswax. Cultural: religious and aesthetic value.

  3. Forests, Biodiversity: Biodiversity is important not only for the stability of local ecosystems. As the “world’s genetic library,” biodiversity is a global public resource, with immeasurable potential for pharmaceutical and agricultural research, as well as intrinsic value for science and humanity. From this perspective, why are forest ecosystems so important?

    • (from GEO-4 “Forests”) Forests host a large proportion of Earth’s terrestrial biodiversity. Conserving forest biodiversity will make forests themselves more resilient, and support human social relations, health, and freedom of choice and action – especially for the poor.


Most people do not live in mountainous regions yet approximately one in two depend on mountains as the original source of the their water supply. As a result, mountains can be a relatively “invisible” partner in the health and well-being of many people. Mountains are often home to forests and disproportionately higher numbers of the poor. They are therefore both a vital resource and a physically challenging environment in which to improve the living conditions of the resident populations. 

Mountains Assignment Questions

  1. Mountains: Explain the role of mountains in the hydrological cycle.

    • (from Why do Mountains…) Mountains collect and store water. Because of their shape, they force moist air upwards, where it condenses and falls as rain or snow. Water stored as snow and ice is released to the lowlands during warmer—and often drier—seasons as it melts. It is estimated that one in two people in the world depend on water that originated in the mountains.

  2. Mountains: What physical characteristics of mountains distinguish their ecosystems?

    •  (from Mountain Watch) Cooler temperatures and higher rainfall than the surrounding area. The temperature decreases with increasing altitude. The fast run-off of water because of lack of permafrost means plants are adapted to water scarcity. Rapid changes in altitude create distinct habitats in close proximity, leading to high biodiversity.

Ecosystems Discussion Questions

  1. What should regional and global priorities be in protecting ecosystems and biodiversity? Consider what criteria you are using to make your judgment.
  2. There has been a shift in environmental communities from thinking about sustainability simply in terms of minimizing pollution and reducing deforestation, to trying to understand how to support and maintain ecosystem functioning as a whole. Do you see this as an important change? Why or why not?