How do human activities affect the environment, and what can we do to reduce the harm?
Describe how human activities such as pollution and deforestation affect the environment, and outline ways to conserve resources and reduce harm
A focused N(A)-Level answer on human impact. The effects of pollution and deforestation, the importance of biodiversity, and practical ways to conserve resources and reduce harm.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
SEAB wants you to describe how human activities such as pollution and deforestation harm the environment, and to outline ways to conserve resources and reduce that harm. The central idea is that a growing human population puts pressure on the environment, but careful choices can reduce the damage.
The answer
Pollution
Human activity adds harmful substances to the environment:
- air pollution from burning fossil fuels adds carbon dioxide (global warming), sulfur dioxide (acid rain) and other gases,
- water pollution from sewage, fertilisers and chemicals can poison rivers and kill water life,
- land pollution from waste and litter spoils habitats.
Deforestation
Cutting down large areas of forest causes several problems:
- loss of habitats, so many species die out and biodiversity falls,
- more carbon dioxide in the air, because fewer trees remove it by photosynthesis, adding to global warming,
- soil erosion, because tree roots no longer hold the soil in place,
- less oxygen released into the air.
Why biodiversity matters
Biodiversity is the variety of different living things in a habitat. A wide variety makes an ecosystem more stable and gives us resources such as food and medicines. Losing species reduces this variety and can damage food webs.
Conserving resources and reducing harm
People can reduce their impact in many practical ways:
- reduce, reuse and recycle materials such as glass, paper, metal and plastic to save raw materials and cut waste,
- use renewable energy sources (such as solar, wind and hydroelectric power) that will not run out and cause less pollution than fossil fuels,
- replant trees (reforestation) and protect habitats as nature reserves,
- treat sewage and control the use of fertilisers and chemicals.
Examples in context
Example 1. Why countries protect their forests. Forests store carbon, release oxygen and shelter huge numbers of species. Protecting them as reserves keeps biodiversity high and helps slow global warming, which is why many countries limit logging and replant cleared areas.
Example 2. Switching to solar power. Replacing a coal power station with solar panels removes the carbon dioxide and sulfur dioxide that coal releases. Because sunlight will not run out, solar is a renewable source that reduces both pollution and the use of finite fossil fuels.
Try this
- Cue. State two harmful effects of deforestation. Any two of: habitat loss (lower biodiversity), more carbon dioxide, soil erosion, less oxygen.
- Cue. Define a renewable energy source and give an example. A source that will not run out, such as solar, wind or hydroelectric power.
- Cue. Explain why recycling helps the environment. It saves raw materials and energy and reduces the waste sent to landfill.
Exam-style practice questions
Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Original4 marks(a) State two harmful effects of cutting down large areas of forest (deforestation). (b) Suggest one way these effects could be reduced.Show worked answer →
(a) Any two of: loss of habitats so fewer species (lower biodiversity); more carbon dioxide in the air (fewer trees to remove it), adding to global warming; soil erosion as roots no longer hold the soil; less oxygen released.
(b) Replanting trees (reforestation), or protecting forests as reserves, or using wood from managed, sustainable forests.
What markers reward: two correct effects of deforestation, and a sensible way to reduce the harm such as replanting or protecting forests.
Original3 marks(a) Explain why recycling materials such as glass and metal helps the environment. (b) State what is meant by a renewable energy source and give one example.Show worked answer →
(a) Recycling means materials are used again instead of thrown away, which saves raw materials and energy and reduces waste sent to landfill.
(b) A renewable energy source is one that will not run out (it is naturally replaced). An example is solar (Sun), wind, or hydroelectric (water) energy.
What markers reward: recycling saving raw materials and reducing waste, and a correct definition of renewable energy with a valid example.
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