Lesson Notes By Weeks and Term v5 - Grade 9

Lesson Video

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Performance objectives

• Identify three major ways humans impact the environment in South Africa.
• Explain the causes and consequences of air, water, and land pollution.
• Discuss the impact of deforestation and habitat destruction.
• Describe the greenhouse effect and its link to climate change.
• Suggest practical actions to reduce our environmental impact.

Lesson summary

The environment around us provides everything we need to survive: clean air to breathe, clean water to drink, fertile soil to grow food, and natural resources for building and creating.

However, human activities are putting immense pressure on these resources, leading to pollution, habitat destruction, climate change, and loss of biodiversity. In South Africa, these impacts are particularly concerning. For example, water scarcity is a growing problem exacerbated by pollution from mining and agriculture. Loss of biodiversity affects not only our natural heritage but also important sectors like tourism and traditional medicine.

Lesson notes

2.1 Major Human Impacts on the Environment: Pollution: This involves introducing harmful substances into the environment. It affects air, water, and land.

Air Pollution: Caused by the release of harmful gases and particles into the atmosphere. Sources include burning fossil fuels (coal, oil, gas) for electricity and transportation, industrial processes, and burning waste. In South Africa, coal-fired power plants are a major source of air pollution, particularly in areas like Mpumalanga. This leads to respiratory problems, acid rain, and smog.

Water Pollution: Occurs when harmful substances contaminate water bodies like rivers, lakes, and oceans. Sources include industrial waste, agricultural runoff (fertilizers and pesticides), sewage, and mining activities. In South Africa, acid mine drainage (AMD) from abandoned mines poses a significant threat to water resources, polluting rivers and groundwater with heavy metals. This renders water unsafe for drinking and irrigation and harms aquatic life. Imagine the Vaal River system, a critical water source, being severely polluted by untreated sewage and industrial discharge.

Land Pollution: Results from the disposal of solid waste (garbage), industrial waste, and agricultural chemicals on land. Improper waste management, like open dumping, leads to soil and water contamination. In South Africa, illegal dumping of electronic waste (e-waste) containing hazardous materials is a growing concern. This pollutes the soil and can leach into groundwater, posing risks to human health and the environment.

Deforestation: This is the clearing of forests for other land uses, such as agriculture, urbanization, and mining. Forests play a vital role in absorbing carbon dioxide, regulating water cycles, and providing habitat for countless species. Deforestation contributes to climate change, soil erosion, and loss of biodiversity. In South Africa, deforestation occurs due to unsustainable logging practices, clearing land for agriculture, and urbanization, particularly in coastal forests and indigenous woodlands.

Habitat Destruction: This involves the destruction or alteration of natural habitats, making them unsuitable for the species that live there. Habitat destruction is a major driver of biodiversity loss. Causes include urbanization, agriculture, mining, and infrastructure development. For example, the expansion of sugarcane plantations in KwaZulu-Natal has led to the destruction of grasslands and wetlands, impacting the habitat of various bird species and other wildlife.

Overexploitation of Resources: This refers to using natural resources at a rate faster than they can be replenished. This includes overfishing, overgrazing, and unsustainable mining practices. In South Africa, overfishing has depleted fish stocks in some areas, threatening the livelihoods of fishing communities and disrupting marine ecosystems.

Climate Change: This refers to long-term changes in temperature and weather patterns. It is primarily caused by the increase in greenhouse gases (carbon dioxide, methane, nitrous oxide) in the atmosphere due to human activities, such as burning fossil fuels and deforestation. Climate change leads to rising sea levels, more frequent and intense droughts, floods, and heat waves. In South Africa, climate change is predicted to lead to increased water scarcity, crop failures, and displacement of communities. 2.2 The Greenhouse Effect and Climate Change: The greenhouse effect is a natural process that keeps the Earth warm enough to support life. Greenhouse gases in the atmosphere trap some of the sun's heat, preventing it from escaping back into space.

However, human activities have increased the concentration of these gases in the atmosphere, enhancing the greenhouse effect and causing the Earth to warm up.