Environmental Management and Sustainable Development (Senior 4 General and Religious Studies): free lessons | Ganzaa

Environmental Management and Sustainable Development

Lessons

Senior 4 · General and Religious Studies

Environmental Management and Sustainable Development

4 lessons

Lesson 1 of 4

Rwandan and Global Environmental Degradation

25 min

Two pictures from space

The two satellite images below show the same part of north-western Rwanda, with Lake Kivu on the left and the Virunga volcanoes at the top. Look for the dark green patch left of centre: Gishwati forest.

In fifteen years a natural forest became farmland and tea estates. This is environmental degradation: the environment loses its quality and its ability to support life. Gishwati's story did not end there (Lesson 2 shows how it is being restored), but it shows the speed with which people can change land.

Definition

Environment: Rwanda's Law N° 48 of 2018 distinguishes the natural environment ("all living species and non-living things occurring naturally on earth, including soil and subsoil, water, air, biodiversity, and landscapes ...") from the built environment ("man-made surroundings that provide the setting for human activities").

Environmental degradation: the deterioration of the environment through the loss or pollution of soil, water, air, forests and living species.

Deforestation: the clearing of forest for another use, such as farming, settlement or plantations. Soil erosion: the removal of fertile topsoil by water or wind.

Pollution: "the contamination caused by waste, harmful biochemical products derived from human activities that may alter a person's habitat and cause adverse effects" (Law N° 48 of 2018, Article 2).

Wetland: an area of marsh, fen, peatland or water, natural or artificial, permanent or temporary (Law N° 48 of 2018). Biodiversity: the variety of living things in an area.

Degradation in Rwanda

Problem	Evidence
Soil erosion and land degradation	Around 90% of Rwanda's territory lies on slopes; a survey by the Rwanda Water Resources Board found about 46% of the country's area exposed to some form of soil erosion risk, with Ngororero and Muhanga among the most affected districts (REMA, 2021)
Loss of natural forest	Gishwati (above). Total forest area has grown, but natural mountain rainforest is only 18.1% of it (Figure 1)
Wetland destruction	By 2003 an estimated 56% of the Rugezi wetland had been destroyed by drainage, farming and uncontrolled fishing; factories and warehouses of the Gikondo industrial park had been built in a Kigali wetland (REMA, 2021)
Pressure on wood	In 2022, 76% of private households used firewood as their main cooking energy, and 93% in rural areas (NISR, 2022 census)
Pollution	Industrial waste from Gikondo reached the Nyabugogo wetland belt (REMA, 2021); plastic bags were banned in 2008 and single-use plastics in 2019
Population pressure	501 people per square kilometre in mid-2022, projected to reach about 894 by 2052 (NISR)

Figure 1: more forest, but mostly planted. Data: Rwanda Environment Management Authority, State of Environment and Outlook Report 2021, citing the Ministry of Environment (2019); drawn by Ganzaa.

Degradation in the world

Climate change. The World Meteorological Organization confirmed that 2024 was the warmest year on record, at about 1.55 °C above the pre-industrial level, and that the past ten years were all in the top ten (WMO, 10 January 2025).
Land degradation and desertification. The UN Convention to Combat Desertification states that over 75% of the Earth's land has been transformed from its natural state and almost a quarter is degraded; the United Nations reports that drought and desertification degrade 100 million hectares of productive land each year.
Shrinking water bodies. The open water of Lake Chad, shared by Chad, Cameroon, Niger and Nigeria, fell from about 25,000 km² in 1960 to about 2,000 km² in 1980, through climate change and water diverted by people; it is no longer thought to be shrinking.

Warning

"More trees" is not the same as "a healthy forest". Rwanda's forest area grew from 618,000 hectares (2011) to about 725,000 hectares (2019), which covers about 30.4% of the land. But most of the gain is plantations and agroforestry. A eucalyptus plantation stores carbon and supplies wood, yet supports far less biodiversity than a natural rainforest such as Nyungwe. When you evaluate environmental progress, ask what kind of change the figure measures.

Tip

Soil, water, air, life. Sort any example of degradation into one of four headings: soil (erosion, exhaustion), water (wetlands, pollution, shrinking lakes), air (smoke, emissions) and life (loss of forests and species). Then give a cause, an effect and a place.

Important

Discuss. Rwanda has one of the highest population densities in Africa and most families farm. Is environmental degradation in Rwanda mainly a result of population pressure, of poverty, or of past policy choices? Use at least two pieces of evidence from this lesson.

UNCCD (United Nations Convention to Combat Desertification): "Land Degradation Neutrality: why it matters, how it's done" (short version), about 6 minutes. Note how much of the world's land has been transformed and degraded, and what "neutrality" means.

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Practice

Define environmental degradation, deforestation and pollution.
Distinguish the natural environment from the built environment, using Law N° 48 of 2018.
Describe what the two satellite images of Gishwati show.
Give three forms of environmental degradation in Rwanda, each with evidence and its source.
Using Figure 1, calculate the increase in forest area from 2011 to 2019, in hectares and as a percentage of the 2011 area.
Using the figures for Lake Chad, by what percentage did its open water shrink between 1960 and 1980?
"Rwanda's environment is improving because its forest area is growing." Evaluate this statement.

Show answersHide answers

Environmental degradation: the deterioration of the environment through loss or pollution of soil, water, air, forests and species. Deforestation: clearing forest for another use. Pollution: contamination by waste and harmful products from human activities that can harm people's habitat.
The natural environment is everything that occurs naturally (soil, water, air, living things, landscapes); the built environment is the man-made surroundings for human activity, such as buildings and roads.
In 1986 a large block of dark green natural forest; in 2001 most of it had been cleared, and tea estates occupied the central and northern parts of the reserve, with some plantations.
Soil erosion: about 46% of the land exposed to erosion risk (REMA, 2021). Wetland destruction: 56% of Rugezi destroyed by 2003 (REMA, 2021). Pressure on wood: 76% of households cook mainly with firewood (NISR, 2022).
725,000 − 618,000 = 107,000 hectares; 107,000 ÷ 618,000 × 100 ≈ 17.3%.
(25,000 − 2,000) ÷ 25,000 × 100 = 23,000 ÷ 25,000 × 100 = 92%.
Partly true. Forest area rose by about 17% from 2011 to 2019 and covers about 30.4% of the land, which reduces erosion and stores carbon. But natural rainforest is only 18.1% of the forest; much of the gain is plantations with low biodiversity; and soil erosion risk (46% of land), wetland loss and firewood use remain serious. Conclusion: one important indicator is improving, not the whole environment.

Quick check

Match each Rwandan problem to its evidence.

Tap one on the left, then its partner on the right.

Key points

Environmental degradation is the loss of quality of soil, water, air and living things; it includes deforestation, soil erosion, wetland destruction and pollution.
Rwanda: about 90% of land on slopes and 46% exposed to erosion risk; 56% of Rugezi wetland destroyed by 2003; 76% of households cooking with firewood (2022); 501 people per km² (2022).
Forest area rose from 618,000 ha (2011) to about 725,000 ha (2019), but natural forest is only 18.1% of it.
World: 2024 was the warmest year on record at about 1.55 °C above pre-industrial levels (WMO); almost a quarter of land is degraded (UNCCD).

Sources and credits

Rwanda State of Environment and Outlook Report 2021, Rwanda Environment Management Authority: slopes and erosion risk (section 5.2), forest cover and composition (chapter 4), Rugezi (Box 2-4) and Gikondo (Box 6-1).
Law N° 48 of 2018 on environment and Law N° 17 of 2019 on plastic carry bags and single-use plastic items, via RwandaLII: definitions quoted; the 2008 ban is the law repealed by Article 19 of the 2019 law.
Fifth Population and Housing Census 2022: Main Indicators Report, NISR: cooking energy and population density.
WMO confirms 2024 as warmest year on record, World Meteorological Organization, 10 January 2025.
Global land figures from the descriptions of the UNCCD video embedded here and of the United Nations video "Desertification: 5 Facts" (2024).
Lake Chad, Wikipedia contributors, CC BY-SA 4.0: the area figures; adapted by Ganzaa.
Images: Gishwati Forest 1986 and Gishwati Forest 2001, Jesse Allen (NASA Earth Observatory), Landsat data from USGS, public domain, via Wikimedia Commons.
Video: "Land Degradation Neutrality: why it matters, how it's done" (short version), UNCCD, embedded from YouTube.

Written by Ganzaa: Figure 1, the tables, the analysis and the exercises.

This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.

1Two pictures from space

2Degradation in Rwanda

3Degradation in the world

Two pictures from space

Degradation in Rwanda

Degradation in the world