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Study Session 1  Human Interactions with the Environment


This Module is about the context and background to water, sanitation and hygiene (WASH) in Ethiopia. The WASH sector is concerned with provision of safe water, the separation and management of wastes, and promotion of hygienic practices to improve people’s health and well-being. To understand the context of the WASH sector you need to understand the nature of the interactions between us as human beings and our environment.

Humans need to interact with the environment to obtain our food, water, fuel, medicines, building materials and many other things. Advances in science and technology have helped us to exploit the environment for our benefit, but we have also introduced pollution and caused environmental damage. The impact of environmental problems on humans is significant, affecting all human activities, including health and socio-economic development. In this study session you will learn about the relationships between humans and the environment, and the ways in which we use environmental resources. This study session introduces you to many of the topics that are further developed later in the Module.

Learning Outcomes for Study Session 1

When you have studied this session, you should be able to:

1.1  Define and use correctly all of the key words printed in bold. (SAQs 1.1 and 1.3)

1.2  Describe the relationships between human activities and the environment and explain the importance of creating a better environment. (SAQ 1.2)

1.3  Describe the ways in which humans use natural resources and give examples of problems caused by over-exploitation. (SAQ 1.3)

1.4  Give examples of positive and negative ways in which technology affects the environment. (SAQ 1.4)

1.1  Relationships between human activity and the environment

Our environment means our physical surroundings and the characteristics of the place in which we live. It also refers to the wider natural world of land, sea and atmosphere. Humans have been interacting with their environment since people first walked the Earth. For example, humans have been cutting down forests to clear land to grow crops for centuries and by doing so we have altered the environment. Conversely, the environment affects us in many different ways as well. A simple example is the way we change our clothes in response to cold or hot weather. In this section we will introduce some of the ways in which humans influence their environment and how the environment influences us, both positively and negatively.

A good climate, accessible clean water, fertile soil, etc. are aspects of the physical environment that enable people to live and thrive. However, harsh environments, such as a very hot climate, limited water and infertile land, make it more difficult for people to survive. We are also affected by major environmental events such as earthquakes, floods and drought that damage homes, property and agriculture. These can lead to the displacement of people and can cause injury, loss of life and destruction of livelihoods. They can also damage water sources and pipelines, causing water contamination and spreading waterborne diseases. In Study Session 10 you will learn more about the effects of floods and droughts.

Our relationship with the environment changed with industrialisation, which began in the 18th century in the UK, shortly followed by elsewhere in Europe and North America, and then spreading across the world. Prior to industrialisation, the impacts of human activity were not very significant because the technologies used were not capable of modifying the environment on a large scale. People at that time lived in agricultural societies using hand tools and simple technologies with limited environmental impact (Figure 1.1). Industrialisation has allowed for a greater exploitation of resources. For example, we now use powerful chainsaws to cut down trees and industrially produced chemical fertilisers and pesticides for crop production. These changes have rapidly increased the human impact on the environment.

The links between human activity and the environment are complex and varied, but can be grouped into two main types of activity:

  • use of natural resources such as land, food, water, soils, minerals, plants and animals
  • production of wastes from a range of activities including agriculture, industry and mining, as well as wastes from our own bodies.

These are described in the following sections.

Figure 1.1  Fishing on Lake Awassa using simple technologies.

1.2  Use of natural resources

We use many different types of natural resources in our daily lives. We depend on food and water for survival and we need energy for many different purposes, from domestic cooking through to major industrial processes. Our clothes, transport, buildings, tools and all other items we use require many different resources for their production. Let’s take a simple example. Think about the resources that have been used to produce a notebook of the type you may be using right now as you study this Module. Manufacturing the paper needed raw materials of wood and water as well as energy for the production process. The trees that supplied the wood required soil, water and land to grow on. There may be ink or metal staples or other components in your notebook that were made from other types of resources. Our need for resources is vast and it is growing as the population increases and consumption per person increases with socio-economic progress. Depletion of natural resources by extraction and exploitation is especially of concern for non-renewable resources (see Box 1.1).

Box 1.1  Renewable and non-renewable resources

The resources we use can be classified as renewable or non-renewable. The basic difference between the two is the rate at which they are regenerated back into a usable form, relative to the rate at which they are used by humans. Non-renewable resources cannot be replenished by natural means as quickly as the rate at which they are consumed. They include minerals and fossil fuels such as oil, coal and gas, which are formed over millions of years by natural processes from decayed plants and animals.

Renewable resources are constantly available or regenerated over short timescales by natural processes. Some renewable resources, such as solar energy, are not modified or used up by humans. Others, such as water, are altered when we use them and can be over-exploited or damaged such that the resource is no longer available for use.

  • Can you suggest some other renewable resources that are replenished naturally but need to be managed properly and not over-exploited?

  • You may have suggested examples such as wood, animals and plants. For example, trees are cut down to provide wood and they will regrow but they need time to regenerate.

Globally, both population and resource extraction increased by almost 50% in the 25 years from 1980 to 2005 (SERI et al., 2009). Over that time, the world population increased from 4.44 billion in 1980 to 6.49 billion. Figure 1.2 shows how the extraction of natural resources increased between 1980 and 2005 from 40 billion tonnes to 58 billion tonnes. The graph shows the extraction of four types of natural resource: fossil fuels, biomass, metals and minerals. Biomass means biological material derived from living organisms such as crops, livestock, fish, wood, etc. Metals are used in the manufacture of a wide range of goods – from cars to computers. Minerals are used in industrial processes and in construction to build our houses and roads. Both metals and minerals are obtained from rocks that have been mined and are then processed in various ways to extract the valuable resource.

Figure 1.2  Global extraction of natural resources, 1980 to 2005. (SERI et al., 2009)
  • Look at Figure 1.2. What is the pattern of natural resource extraction from 1980 to 2005 and what do you think could be the reason?

  • Natural resource extraction shows a steady increase from 1980 to 2005, with the greatest amount extracted in the most recent year (2005). The most likely reason is the increase in the global population in this period; more people need more resources. It could also be the case that the amount used by individuals and by wider society is increasing due to changes in behaviour and levels of consumption.

Advances in technology have increased natural resource exploitation by enabling people to reach new resources and to exploit more resources per capita (per person). For example, fishermen who use traditional technologies such as small boats are limited in the number of fish they can catch. Modern industrial fishing fleets use very large ships that cover huge areas of ocean at greater depths to catch many more fish. This can lead to overfishing, which means catching fish at a faster rate than they can reproduce.

  • Are fish a renewable or non-renewable resource?

  • Fish are a renewable resource. However, if fishing is not managed properly and more fish are taken from the water than can be replaced naturally, the fishery will fail.

Overfishing and other examples of over-exploitation of natural resources can result in damage to or the loss of entire ecosystems.An ecosystem includes all the living organisms (humans, plants, animals, micro-organisms) and their physical environment (soil, water, air, land) and the interactions between them. If one component of the system is removed, this can have knock-on effects on the other parts of the system.

1.2.1  Deforestation

One particular problem caused by over-exploitation of natural resources is deforestation, which occurs when forest areas are cleared and the trees are not replanted or allowed to regrow. In Ethiopia, clearing land for agriculture to meet the food needs of the growing population and the demand for fuel and construction materials has resulted in a steady loss of forest area, which is still continuing as you can see from Figure 1.3.

Figure 1.3  Proportion of land area in Ethiopia covered by forest (%) from 2002 to 2010. (MoFED, 2012a)

The loss of forest has several undesirable consequences. Forests are home to many different types of trees, as well as other plants, and a wide range of animals from insects to birds and mammals. The conversion of forests to agriculture greatly reduces biodiversity, which is a measure of the variety of living organisms (all life forms). Biodiversity is important for humans because we use other living organisms to provide several essentials:

  • Food: we use plants and animals such as fish, goats, wheat, rice and maize as sources of food.
  • Medicines: many traditional medicines are made from plants and animals and new medicines are developed from them.
  • Ecological services: living organisms, especially plants and micro-organisms, play an important role in processes that maintain our lives and environment such as providing oxygen, cleaning the air, purifying water, breaking down wastes and controlling erosion.

Deforestation is a significant contributory cause of soil erosion. Once the trees and undergrowth are removed, the underlying ground is exposed. Without the intercepting effect of the vegetation and the tree roots binding the soil together, the soil is more likely to be washed away when it rains. Loss of forests also has a significant impact on water supply. Tree roots reach deep into the soil and create spaces between the particles which increases soil permeability, allowing rainwater to soak in and replenish groundwater. (Permeability means the ease with which water moves through soil or rock.)

1.2.2  Energy resources

The use of renewable or non-renewable resources is a critical factor when considering energy resources. Fossil fuels have been the main energy source for global industrialisation, but because they are non-renewable, the quantity is ultimately limited and their use is not sustainable over the long term. Furthermore, burning of fossil fuels is the main cause of climate change. (Climate change is discussed fully in later study sessions.) There are several renewable alternatives to fossil fuels. Wood used as a fuel is renewable in the sense that trees will regrow but there are other disadvantages such as deforestation, as you have read. In Ethiopia, windfarms are harnessing wind power to generate electricity (Figure 1.4) but the most important source of renewable energy in Ethiopia is water. Ethiopia already has several hydropower stations and more are planned, including the Grand Ethiopian Renaissance Dam, currently under construction. Hydroelectric power is renewable because it makes use of the energy of flowing water but does not use up the water in the process. Another renewable energy source is solar power, using photovoltaic cells that convert the sun’s energy into electricity.

Figure 1.4  Windfarm at Ashegoda, Tigray Region.

1.2.3  Water resources

You may have noticed that the four categories of resources shown in Figure 1.2 do not include water, and yet this is one of our most vital resources and is obviously central to the WASH sector. The direct use of water by people falls into three main categories:

  • domestic uses, including drinking, washing and cooking
  • agricultural uses, principally irrigation
  • industrial uses, in manufacturing processes and for energy generation.

The relative proportions of these three categories vary in different parts of the world, but globally the sector using the most water is agriculture (FAO, 2012) (Figure 1.5).

Figure 1.5  Global water withdrawal by sector. (Adapted from FAO, 2012)

As well as direct use of water for human activities, water is also essential for the environment and to maintain biodiversity. Rivers, lakes and wetlands are important habitats for wildlife and need a minimum amount of water at all times. This becomes a problem when the demand for water for human activities exceeds the supply.

Water is not an endlessly renewable resource. In many parts of the world water demand is significantly above sustainable water supply. Sustainable water supply means there are adequate supplies, in both quality and quantity, to meet the current and future needs of people and of the environment.

Many countries are already experiencing water stress or scarcity. These terms refer to the volume of water available relative to the use and demand for it, which is linked to the population served. Figure 1.6 shows the availability of freshwater across the world. Countries which have less than 1700 m3 of water per person per year for all purposes are defined as water stressed (United Nations, 2014). Water scarce countries have been defined as those with less than 1000 m3 of water per person per year. These precise figures should be used with caution, however, because they do not recognise variations between countries and they hide the underlying causes of water scarcity.

Figure 1.6  Global freshwater availability in cubic metres (m3) per person per year (2007). (Note that although calculated ‘per person’, these figures apply to all uses of water not just personal use.) (WWAP, 2012)

Increasing water demand leads to unsustainable use of water resources. By the actions of the water cycle (which you will learn about in Study Session 4) water supply is replenished, but taking excessive amounts of water from rivers and groundwater for domestic, industrial and agricultural use decreases the amount of water available for current and future generations. Globally, water withdrawals have tripled over the last 50 years due to population growth and to increased consumption per person. Many areas with plentiful supplies can sustain this use, but in some countries the future may bring water shortages unless demand is managed.

  • If the trend for increased consumption continues, what could be the result for Ethiopia?

  • As you can see from Figure 1.6, Ethiopia is already classed as being under water stress. If consumption increases due to population growth and/or increased use per person, this could put Ethiopia into the water scarcity category.

In practice, for Ethiopia, the problem of water supply is not so much about the volume of water that is available. The problem is the infrastructure and investment required in delivering adequate quantities of safe water to all the people wherever they live. The availability of water and access to a safe supply varies considerably throughout the country and between rural and urban populations.

Case Study 1.1 illustrates the problems that can arise from excessive water use.

Case Study 1.1 Effects of water use on Lake Alemaya

Lake Alemaya in the Ethiopian Highlands has always provided local people with water for drinking and domestic use, for irrigating crops, watering livestock and fishing. In the mid-1980s it was around 8 m deep and covered 4.72 km2. However, by 2005 the amount of water in the lake had dropped dramatically (Figure 1.7) and the size of the lake had fallen (UNEP, n.d. 2).

Figure 1.7 Loss of water from Lake Alemaya, between 1986 and 2005. (UNEP, n.d. 2)

It is believed that changes in water use by local people and changes in the local climate are responsible. The use of domestic water and also water for irrigation (especially for growing khat) has increased significantly. Deforestation of the surrounding area, as land is cleared for farming and to meet an increasing need for wood, means that tree roots no longer hold the soil together and it is washed off the hillsides into the lake. This causes it to silt up and reduces the capacity of the lake. Warming of the local climate may also have had an effect, increasing the rate of evaporation from the lake. Recently, lack of water in the lake has interrupted water supply to Harar, a nearby town of over 100,000 people.

  • What are the possible causes of the loss of water from Lake Alemaya?

  • Increased use of water for domestic uses and for irrigation, deforestation leading to soil erosion and silt deposition in the lake, and possibly climate change.

1.3  Production of waste and pollutants

Following on from our use of natural resources, it is inevitable that wastes are produced. For the WASH sector, the most important of these is our own bodily wastes. The impacts of open defecation and inadequate sanitation on human health and on the wider environment are profound. Waterborne diseases are caused by pathogens (disease-causing agents) in water and food that have been contaminated by the wastes from infected people. Preventing this connection between human wastes and the intake of contaminated water is the primary goal of WASH services.

Industry, agriculture and energy production all generate wastes that can pollute air, water and soil. Pollution means the introduction into the environment of substances liable to cause harm to humans and other living organisms. For example, the leather industry produces large amounts of liquid wastes from the tanning process. These wastes contain organic materials such as fat from the hides and toxic (poisonous) chemicals including some human carcinogens (cancer-causing agents). Another example is the release of so-called greenhouse gases such as carbon dioxide, methane and nitrous oxide, which contribute to human-induced climate change. (Pollutants and pollution are the topics of Study Sessions 7 and 8 and climate change is described in more detail in Study Session 9.)

Figure 1.8 summarises the interactions between ‘human activities’ and ‘the environment’. The green arrow indicates the waste generated as a product of this interaction. The red arrows indicate thenegative effect on both the environment and humans if the waste is not properly managed.

Figure 1.8  Human–environment interaction and the generation of waste and pollutants.

1.4  Technology and the environment

Technologies have transformed transport, industry, communications and our lives at home and work. For instance, gadgets such as mobile phones, computers, televisions, microwave ovens and refrigerators have improved living standards for those people who can afford them. Technology can also improve the quality of our environment. For example, energy can be generated from renewable sources such as wind and solar power, which reduces our reliance on non-renewable energy sources such as fossil fuels, and also helps to reduce the release of polluting gases to the atmosphere.

Another example of the benefits from technology is the highly advanced eco-friendly wastewater treatment plant at the St. George Brewery in Addis Ababa. This plant recovers nutrients and waste water from the brewery that would otherwise be released into the environment. This type of technology can help to alleviate the problem of water shortage, prevent surface water pollution and protect the environment.

Although technology has many positive impacts on people and the environment, it also has negative impacts, including the production of toxic waste from technological processes and electronic gadgets that are thrown away when they reach the end of their useful lives, as illustrated in Case Study 1.2.

Case Study 1.2  E-waste in Ethiopia

When electronic equipment or gadgets get old or stop working they are often thrown away. This type of electronic waste is referred to as e-waste. E-wastes pose a huge challenge to the environment because they contain toxic substances such as cadmium and lead from batteries, which leach out and pollute rivers and groundwater. (Leaching means the substances seep out or are washed out by rain into the soil below.) Toxic substances may get into the soil, making it unfit for agriculture. Copper from wiring is valuable for recycling, but if wiring is burned, it produces very hazardous air pollution.

E-waste is becoming a major problem in many African countries, including Ethiopia, where the use of electrical equipment has increased sharply with the rising number of people on higher incomes. According to a United Nations University report, there are about 4300 tonnes of non-functioning computers, televisions, mobile phones and refrigerators in Ethiopia, mostly in the ten largest cities (Manhart et al., 2013).

As there is no proper e-waste management system in Ethiopia, some e-wastes are disposed of together with other household wastes or dumped in an uncontrolled way that may cause huge environmental problems. Figure 1.9 shows open solid waste disposal sites in Addis Ababa and Bahir Dar close to residential areas. All types of waste, including hazardous waste like heavy metals, are discarded here without any treatment, so toxins can seep into the soil and groundwater. (Hazardous waste is any waste that contains material that is potentially harmful, for example, toxic, infectious, corrosive, explosive or flammable materials.)

Figure 1.9 Uncontrolled waste disposal in Bahir Dar (top) and Addis Ababa (bottom).

There is one e-waste demanufacturing facility (DMF) in Addis Ababa managed by the government. The DMF collects e-waste from governmental offices, dismantles them manually and sorts the different components to recover valuable metals (Figure 1.10), which is an example of good practice in e-waste disposal.

Figure 1.10 Computer dismantling in the Demanufacturing Facility in Akaki, Ethiopia.

1.5  Agriculture and environment

Agriculture is very important in Ethiopia to provide essential food crops and as a source of income, contributing about 46% of our country’s Gross Domestic Product (GDP). About 80% of the labour force in Ethiopia is in the agricultural sector, so it is vital to the livelihoods of the majority of people. However, agriculture also has significant negative impacts on our environment, including loss of biodiversity, pollution, climate change, soil erosion and the use of large amounts of water for irrigation.

  • What problems do you think are caused by using large amounts of water for agriculture?

  • This reduces the amount of water available for other human purposes such as drinking and washing, and for sustaining wildlife and maintaining the levels of rivers and lakes.

Agricultural activities are also major sources of water pollution. Pesticides and fertilisers applied to crops may wash into rivers and leach into soil and groundwater. (These effects are discussed in Study Session 8.)

Poor farming practices, especially on steeply sloping land, are a significant cause of soil erosion in Ethiopia because rainfall washes away the soil particles downhill. Each year more than 1.5 billion tons of soil are lost from the Ethiopian highlands (Tamene and Vlek, 2008). This lost soil is not only a problem for agriculture, it silts up rivers and lakes. Soil erosion and loss of soil biodiversity causes a decline in soil fertility and this in turn reduces agricultural productivity. Good agricultural practices, such as the use of terraces and diversion ditches, can help stop soil being lost from hillsides (Figure 1.11).

Figure 1.11  Good agricultural practices such as building terraces on sloping land helps to conserve soil.

Agriculture also plays a role in causing climate change through the release of greenhouse gases into the atmosphere. For example, fertilisers added to the soil release nitrous oxide and livestock production releases methane from the digestion process in cattle and the decomposition of manure. The use of fossil fuels to power agricultural machines and burning trees to clear agricultural land both release carbon dioxide. In Study Session 9 you will learn more about climate change and the role of greenhouse gases in changing our climate.

1.6  How we can protect and restore our environment

We end this study session with a positive message. Humans not only affect the environment negatively – we can also contribute positively to sustaining it. When we install wastewater treatment plants, protect endangered species and replant forests, we have a positive impact on our environment. Since 2000, huge efforts have been made in Ethiopia to increase the forest coverage through government and NGO reforestation programmes. More than 700 million trees were planted in 2007 alone (AFP, 2010). Figure 1.12 shows people in Konso, Ethiopia, planting trees to celebrate World Environment Day 2012.In some parts of the country where the reforestation programme has been implemented effectively, the community has already started to benefit from environmental improvements, through effects such as creating more spring water, a higher water table, and less soil erosion and flooding (Rinaudo, 2010).

Figure 1.12  World Environment Day 2012 celebration in Konso.

Summary of Study Session 1

In Study Session 1, you have learned that:

  1. Humans and the environment have been interacting since humans first walked the Earth. Humans change their environment both positively and negatively and the environment affects how humans live in many different ways.
  2. The main interactions between humans and our environment can be grouped into the use of resources and the production of wastes.
  3. Resources can be classified as renewable (e.g. water) or non-renewable (e.g. fossil fuels).
  4. Humans are extracting increasing quantities of natural resources from the Earth which is causing problems of over-exploitation, for example through overfishing and deforestation.
  5. Water is used for domestic, industrial and agricultural purposes. Some countries are classed as ‘water stressed’ or ‘water scarce’ because available supply does not meet demand.
  6. Human activities produce many different types of waste which can pollute the environment. One example is e-waste from discarded electronic gadgets such as mobile phones contain many toxic substances that can pollute groundwater, soil and air unless their disposal is well-managed.
  7. Agriculture is the dominant economic activity in Ethiopia and has a significant impact on the use of resources, especially water and soil. It also contributes to climate change through the release of greenhouse gases (e.g. methane from cattle) into the atmosphere.

Self-Assessment Questions (SAQs) for Study Session 1

Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering these questions.

SAQ 1.1 (tests Learning Outcome 1.1)

The Glossary Game: Write down each of the key words printed in bold in this study session. Cut the paper into strips with one word on each strip; fold them and put them into a bowl. Take a strip, read the word and write a definition in your notebook. Then check your definitions with those in the study session.


This game is intended to familiarise you with the terms you will meet again in subsequent study sessions. To find the right answer, you can check the definition written in your own words with that in the study session.

SAQ 1.2 (tests Learning Outcome 1.2)

Which of the following statements are false? In each case explain why it is incorrect.

  • A.As a population increases, the amount of natural resource extraction and consumption increases.
  • B.Agriculture doesn’t have any negative impacts on the environment.
  • C.As a population increases, more waste is produced as a result of increased activity.
  • D.The environment influences human beings, both positively and negatively.
  • E.The impact of human activity on the environment is always damaging.


B is false. Agricultural activity can have significant negative impacts on our environment, including loss of biodiversity, water contamination, climate change, soil erosion and pollution.

E is also false. Some human activity can prevent damage or repair past damage, for example recovery of hazardous materials from waste and reforestation programmes where many trees are planted. It is important to work towards creating a better environment in order to protect our health, and because environmental improvements such as tree-planting can have many beneficial effects, such as creating more spring water, a higher water table, and less soil erosion and flooding.

SAQ 1.3 (tests Learning Outcomes 1.1 and 1.3)

Explain why biomass resources are classified as renewable. Give two examples of biomass resources that can be over-used despite being renewable. What are the consequences of their over-exploitation?


Biomass resources are derived from living organisms. They are renewable because they are replaced by the continuing processes of growth and reproduction. However, they are vulnerable to over-exploitation if they are used more quickly than they can naturally reproduce and regenerate. Overfishing and deforestation are examples of the over-use of biomass resources. The consequences include loss of biodiversity and loss of income for the people who depend on these resources for their livelihood.

SAQ 1.4 (tests Learning Outcome 1.4)

Imagine you have a colleague who always blames technology for environmental problems. What would you say to your colleague to demonstrate that technology affects the environment in both a positive and a negative manner?


You could start by saying that technology plays an important role in improving the quality of our lives and our environment. For example, we use renewable energy such as wind and solar power to reduce the release of greenhouse gases, and we use high-tech waste treatment plants to protect water sources from pollution. But you would agree that technology can also damage the environment. For example, e-wastes contain many toxic substances that can pollute groundwater, soil and air. So your conclusion is that technology can have both positive and negative environmental impacts.