Cambridge IGCSE Geography (0460): Theme 3.7 – Environmental risks of economic development – Study Guide

This guide covers section 3.7 Environmental risks of economic development of the Cambridge IGCSE Geography (0460) syllabus for examination in 2025 and 2026, Version 2 (published November 2022). Section 3.7 is the last part of Theme 3: Economic development. Theme content is assessed in Paper 1 Geographical Themes (1 hour 45 minutes, 75 marks), where you answer three 25-mark questions, one from each section. Paper 2 Geographical Skills can also set knowledge questions based on the three themes, so pollution or land-use data may appear there too.

Use this guide with the Environmental risks revision notes and the Environmental risks practice questions. Track your progress on the Cambridge IGCSE Geography hub and the IGCSE Geography checklist.

What the syllabus asks for

Syllabus reference	What you must know or be able to do (from the document)	Where assessed
3.7	Describe how economic activities may pose threats to the natural environment and people, locally and globally	Paper 1; data may appear in Paper 2
3.7 guidance	Threats to the natural environment including soil erosion, desertification, enhanced global warming and pollution (water, air, noise, visual)	Paper 1
3.7	Demonstrate the need for sustainable development and management	Paper 1
3.7	Understand the importance of resource conservation	Paper 1
Case study	An area where economic development is taking place and causing the environment to be at risk	Paper 1

The guidance lists these threats by name, so learn each one. You may add others, such as loss of biodiversity. The syllabus does not name a case study, so your teacher may choose a different one from the case study below.

Economic activities as threats: local and global

Every part of Theme 3 can harm the environment. This section asks you to pull those links together.

Economic activity	Example threats
Farming	Soil erosion, desertification, water pollution from fertiliser, methane from cattle and rice paddies
Industry	Air and water pollution, noise, carbon dioxide from burning fuel
Mining and quarrying	Visual pollution, dust, noise, polluted run-off, loss of habitat
Energy	Carbon dioxide from fossil fuels, oil spills, flooding of land behind dams
Tourism	Litter, sewage, noise, footpath erosion, traffic fumes
Transport	Exhaust fumes, aircraft and road noise, greenhouse gases

Local threats affect the area near the activity: a river polluted by a factory, or dust from a quarry. Global threats affect the whole planet: greenhouse gases from millions of sources add to enhanced global warming. Some threats cross borders, such as acid rain or a polluted river flowing into another country.

The syllabus also says threats to people. Always say who is affected: farmers who lose soil, fishing families who lose catches, or residents who breathe polluted air.

Soil erosion

Soil erosion is the removal of topsoil by water or wind faster than new soil can form. Topsoil holds most of the nutrients, so its loss lowers crop yields.

Causes linked to economic activity

• Deforestation: trees and roots no longer bind the soil or intercept rain.
• Overgrazing: too many animals remove the grass cover.
• Ploughing up and down slopes: furrows act as channels for running water.
• Removing hedges to make larger fields, which exposes soil to wind.

Effects: lower yields, gullies that cut up fields, silt that fills rivers and reservoirs and can increase flooding downstream.

Reducing soil erosion: terracing on steep slopes, contour ploughing (along the slope, not down it), planting shelter belts of trees, keeping crop cover on the land, and controlling the number of grazing animals.

Desertification

Desertification is the degradation of land in dry (arid and semi-arid) areas, so that it becomes more like a desert. It is not deserts “moving”; it is good land being damaged.

Human causes: overgrazing, overcultivation (growing crops every year with no fallow period), cutting trees and shrubs for fuelwood, and poorly managed irrigation that leaves salt in the soil. These pressures grow when population rises.

Natural causes: long droughts and unreliable rainfall. Climate change may make droughts more frequent in some dry regions.

Example: the Sahel. The Sahel is a semi-arid belt along the southern edge of the Sahara in Africa. The Great Green Wall is an African-led response. The African Union endorsed it in 2007. It stretches roughly 8,000 km across the continent, brings together more than 20 countries, and aims to restore 100 million hectares of degraded land by 2030.

Evaluation: the scheme combines tree planting with better farming and new jobs, so it tackles causes as well as symptoms. But progress has been slower than planned, and seedlings planted in very dry land often die unless local people protect and water them. Success depends on local communities, not only on government targets.

Enhanced global warming

The natural greenhouse effect keeps the Earth warm. Gases such as carbon dioxide and methane trap some of the heat given off by the Earth’s surface. Without them the planet would be too cold for most life.

Enhanced global warming is the extra warming caused when human activities add more greenhouse gases to the atmosphere.

Sources: burning coal, oil and gas in power stations, factories and vehicles; deforestation (fewer trees take in carbon dioxide, and burning releases it); methane from cattle, rice paddies and landfill; flaring of gas at oil wells.

Effects: rising sea levels from melting ice and warmer oceans, threatening low-lying coasts; more intense heatwaves, droughts and storms; changing crop yields; loss of coral reefs and other habitats.

This is the clearest global threat. Emissions in one country affect people everywhere. Some of the people most at risk, such as farmers in dry regions or residents of low-lying islands, produce few emissions themselves. Under the Paris Agreement (2015), countries agreed to try to limit warming to well below 2 °C.

Pollution: water, air, noise and visual

The syllabus names four types. Learn a source and an effect for each.

Type	Sources from economic activity	Effects on environment and people
Water	Factory waste, untreated sewage, fertiliser run-off, oil spills, mine waste	Fish die when oxygen falls; algae blooms (eutrophication); unsafe drinking water; lost fishing income
Air	Factory chimneys, vehicle exhausts, power stations, burning forests	Breathing illnesses; smog; acid rain damaging trees and lakes; greenhouse gases
Noise	Airports, motorways, factories, quarry blasting, construction	Stress and poor sleep; wildlife disturbed; lower house prices
Visual	Quarries, spoil heaps, power lines, large factories, wind turbines, litter	Spoils landscapes; can reduce tourism; lowers quality of life

Eutrophication happens when nitrates and phosphates from fertiliser or sewage enter water. Algae grow quickly, then die. Bacteria break down the dead algae and use up the oxygen, so fish suffocate.

Visual and noise pollution are local. Air and water pollution can be local or travel long distances in winds and rivers.

The need for sustainable development and management

Sustainable development was defined by the Brundtland Report, Our Common Future (1987), as development “that meets the needs of the present without compromising the ability of future generations to meet their own needs”.

Sustainable development balances three things:

1. Economic: jobs and incomes.
2. Social: health, fairness and quality of life.
3. Environmental: clean air, water and soil, and healthy ecosystems.

Why it is needed: many resources are finite; damaged land and water cost money to repair; pollution harms health; and climate change threatens future development everywhere.

Sustainable management methods

• Laws and standards: limits on emissions and waste; fines for polluters.
• Environmental impact assessments before new projects are approved.
• Protected areas such as national parks and marine reserves.
• Cleaner technology: filters on chimneys, treatment of factory waste water, renewable energy.
• International agreements, such as the Paris Agreement, for global threats.
• Community involvement, so local people benefit from protecting the land.

Evaluation: laws only work if they are enforced. Poorer countries may lack money for inspectors, and some firms may move to places with weaker rules. Global agreements depend on every country keeping its promises.

The importance of resource conservation

Resource conservation means using natural resources carefully so that they last longer and are not wasted.

• Non-renewable resources (coal, oil, gas, metal ores) are finite. Once used, they are gone.
• Renewable resources (forests, fish, soil, fresh water) can recover, but only if they are used no faster than they renew. Overfishing or pumping groundwater too quickly turns a renewable resource into a disappearing one.

Why conservation matters: it keeps resources for future generations; reduces pollution and waste; cuts greenhouse gas emissions; and saves money.

Methods: the “three Rs” (reduce, reuse, recycle); energy efficiency, such as insulation and efficient engines; switching to renewable energy; fishing quotas; replanting after logging; and water metering.

Case study: oil in the Niger Delta, Nigeria

The Niger Delta in southern Nigeria is one of the largest wetlands in Africa. It has mangrove forests, creeks and farmland, and millions of people depend on fishing and farming. Shell found oil at Oloibiri in 1956. Oil and gas have since provided most of Nigeria’s export earnings and a large share of government revenue. This is economic development that has put the environment at risk.

Threats to the environment and people

• Water and land pollution: thousands of oil spills from pipelines, wells and tankers. Oil coats mangroves and creeks, kills fish and makes farmland infertile.
• Air pollution and enhanced global warming: gas that comes up with oil is often burned off (gas flaring). This releases carbon dioxide, soot and other pollutants. People living near flares report breathing problems.
• Threats to people: loss of fishing and farming income and polluted drinking water.

Ogoniland and Bodo. Ogoniland is an area of about 1,000 km² in the delta. In 2011 the United Nations Environment Programme (UNEP) published an assessment of Ogoniland based on more than 4,000 samples from over 200 sites. It found oil contamination in soil and groundwater at many sites. In one community, drinking water contained benzene, a cancer-causing chemical, at about 900 times the World Health Organization guideline. UNEP estimated that full recovery could take up to 30 years, and that the first five years would need about US$1 billion.

Two spills from Shell Nigeria’s Trans-Niger pipeline, which began in 2008, badly polluted Bodo, a fishing community in Ogoniland. After a case in a London court, Shell agreed in 2015 to pay £55 million: £35 million to individuals and £20 million to the community.

Causes of spills, and different views: spills come from corroded pipelines, equipment failure, and also from sabotage, oil theft and illegal refining. Oil companies tend to stress theft and sabotage. Local communities and campaigners tend to stress poor maintenance and slow clean-up. The Nigerian government both earns oil revenue and regulates the industry. Critics say its laws on spills and flaring have been weakly enforced; the government points to its clean-up agency and its plans to cut flaring. Estimates of how much oil has been spilled vary widely.

Management

• The Nigerian government set up a clean-up agency, the Hydrocarbon Pollution Remediation Project (HYPREP), to act on UNEP’s report. It was first set up in the early 2010s; the Ogoniland clean-up was launched in 2016, and its work has included restoring mangroves.
• Compensation payments, such as the Bodo settlement.
• Efforts to reduce gas flaring by capturing gas for use instead of burning it.

Evaluation: clean-up has been slow and new spills continue, so the area shows how hard it is to manage damage after it happens. The case supports the need for sustainable management from the start: maintained pipelines, strict laws that are enforced, and local people sharing in the benefits. It also shows a global link: flaring adds to enhanced global warming far beyond Nigeria.

Worked example: using the case study

For a named area, explain how economic development has put the environment and people at risk. (7 marks)

In the Niger Delta, Nigeria, oil extraction since the oil discovery at Oloibiri in 1956 has caused many oil spills (knowledge). At Bodo in Ogoniland, two pipeline spills that began in 2008 polluted creeks and mangroves, so fish died and families who depended on fishing lost their income (application). UNEP’s 2011 assessment found oil in soil and groundwater, and drinking water with benzene about 900 times the WHO guideline, which shows that pollution threatens health as well as jobs (analysis). Gas flaring adds carbon dioxide to the atmosphere, so the risk is global as well as local. The greatest risk is long-term, because UNEP estimated recovery could take up to 30 years (evaluation).

The answer names a place, uses real details, links each threat to people, and covers local and global scales.

Worked example: a sustainability judgement

Explain why sustainable management is needed in areas of rapid economic development. (4 marks)

Rapid development often uses resources faster than they can recover, such as overgrazing in dry areas, which can lead to desertification (point and example). Repairing damage later is slow and costly; UNEP estimated about US$1 billion for the first five years of clean-up in Ogoniland (development). Sustainable management, such as enforced pollution laws, keeps jobs while protecting land and water, so future generations can still use them (link to the definition).

Common errors

• Writing “global warming” instead of enhanced global warming, and not saying it is caused by extra human emissions.
• Confusing global warming with the ozone hole. They are different problems.
• Describing desertification as deserts spreading on their own, with no human cause.
• Naming a type of pollution without a source or an effect on people.
• Forgetting noise and visual pollution, which the syllabus names.
• Defining sustainable development only as “protecting the environment”, leaving out future generations and the economy.
• Treating renewable resources as unlimited. Fish, soil and water can be used up.
• Giving a case study with no place names, dates or figures.

Where to go next

• Test yourself with the Environmental risks practice questions.
• Link farming threats to the Food production study guide.
• Link industrial pollution to the Industry study guide.
• See tourism’s environmental effects in the Tourism study guide.
• Compare fossil fuels with renewables in the Energy study guide, and water management in the Water study guide.
• Revise rainforest deforestation in Climate and natural vegetation.
• Use the IGCSE Geography checklist to mark 3.7 as done.

Official syllabus

This guide follows the Cambridge IGCSE Geography (0460) syllabus for examination in 2025 and 2026, Version 2 (published November 2022), section 3.7 Environmental risks of economic development. Check the latest version on the Cambridge International website; your teacher will confirm anything the syllabus does not print.