Form 5 · Common mistakes

Environmental Sustainability, common mistakes

The mistakes SPM students make on Environmental Sustainability, why each one loses marks, and the correct version.

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The mistakes, why they lose marks, and the fix

Common mistake	Why it loses marks	What earns the mark
Believing carbon dioxide and CFCs damage the environment through the same mechanism.	Carbon dioxide contributes to global warming by trapping heat as a greenhouse gas, while CFCs mainly damage the ozone layer through a separate chemical reaction with ozone molecules; some CFCs also act as greenhouse gases, but their most tested effect is ozone depletion, not warming.	Explain carbon dioxide's role in trapping heat and CFCs' role in breaking down ozone as two separate mechanisms.
Treating the 3R principle (reduce, reuse, recycle) as identical to green technology.	The 3R principle describes everyday practices that lower the amount of waste generated or resource extracted, while green technology refers to engineered solutions such as solar panels or wastewater treatment systems; both support sustainability but are not the same category of solution.	Name the 3R principle as a sustainable practice and green technology as an engineered solution when a question asks for one specifically.
Assuming eutrophication only affects lakes.	Eutrophication can occur in any body of slow-moving or enclosed water that receives excess nutrients, including rivers with little current, ponds, and shallow coastal waters near river mouths, not lakes alone.	State that eutrophication can affect lakes, slow-moving rivers and coastal waters wherever nutrient runoff accumulates.
Describing acid rain as a cause of global warming.	Acid rain results from sulfur dioxide and nitrogen oxides dissolving in atmospheric moisture and is a separate effect from the greenhouse effect, which is caused mainly by carbon dioxide, methane and other gases trapping heat.	Keep acid rain and the greenhouse effect as two distinct pollution effects with different causal gases.
Assuming landfill waste becomes harmless once buried.	Biodegradable waste in a landfill still produces methane, a potent greenhouse gas, as it decomposes without oxygen, and non-biodegradable waste such as plastic can persist for centuries, while leachate from both types can seep into and contaminate groundwater.	Explain that landfill waste continues to cause pollution through methane release and leachate, even after burial.
Believing an Environmental Impact Assessment is the same as an operating licence.	An EIA is a scientific study of a project's likely environmental effects carried out at the planning stage, while an operating licence is a separate administrative approval; a project can hold a licence and still be required to complete an EIA before certain approvals are granted.	Describe an EIA specifically as a study of environmental impact conducted before approval, not as a general permit.
Claiming solar and wind energy produce zero environmental impact.	While solar panels and wind turbines produce no emissions while generating electricity, manufacturing, transporting and eventually disposing of the panels or turbines does have some environmental impact, so green technology reduces impact relative to fossil fuels rather than eliminating impact entirely.	State that green technology reduces environmental harm compared with fossil fuel alternatives, rather than claiming it has no impact at all.
Assuming an entire national park is an example of preservation.	A national park often contains different zones: a strictly protected core zone matches preservation, while a buffer zone that allows regulated ecotourism or research matches conservation, so the whole park cannot always be labelled with a single term.	Identify which specific zone or activity within a protected area matches preservation and which matches conservation.
Treating global warming and a single unusually hot day as the same evidence.	Global warming refers to a long-term rise in the average global temperature measured over decades, not the weather on any one day, which can vary for short-term reasons unrelated to climate change.	Refer to long-term average temperature trends as evidence of global warming, not individual weather events.
Assuming restoration always returns an ecosystem completely to its original state.	Restoration actively repairs a damaged ecosystem, such as replanting a cleared mangrove area, but the restored ecosystem may take years to recover and may not regain exactly the same species diversity it had before damage occurred.	Describe restoration as repairing and improving a damaged ecosystem, without claiming it a full return to the original state.
Believing only the burning of fossil fuels increases atmospheric greenhouse gases.	Deforestation also increases atmospheric carbon dioxide by removing trees that would otherwise absorb it through photosynthesis, and livestock farming and decomposing waste release methane, so other activities beyond fossil fuel combustion also add to the greenhouse gas total.	List deforestation, livestock farming and waste decomposition alongside fossil fuel combustion as separate sources of greenhouse gases.
Assuming BOD is measured by directly counting the microorganisms in a water sample.	BOD is measured by finding how much dissolved oxygen is used by microorganisms decomposing organic matter over a set incubation period, not by counting the microorganisms present.	Describe BOD as a measure of oxygen consumed during decomposition, not a count of microorganisms.

How to avoid these mistakes

List the main threats to the environment with a specific cause and effect for each.
Distinguish preservation, conservation and restoration with one example each.
Practise reading BOD values to judge water quality and compare two samples.
Learn the cause-and-effect chain for ozone layer depletion and for eutrophication so you can explain, not just name, each process.
List two renewable energy sources and one other green technology example, with one advantage of each.
Explain the purpose of an Environmental Impact Assessment at the planning stage of a development project.

Frequently asked questions

What is the difference between preservation and conservation?

Preservation means protecting a natural area and keeping it untouched by human use, for example a strict nature reserve. Conservation means using and managing natural resources carefully and sustainably so they are not used up, for example controlled fishing or selective logging. Preservation avoids use; conservation allows wise use.

What does biochemical oxygen demand (BOD) tell us?

Biochemical oxygen demand is the amount of oxygen that microorganisms use to break down the organic matter in a sample of water over a set time. A high BOD means there is a lot of organic pollution, because the microorganisms use a lot of oxygen, which can leave too little for fish and other aquatic life. Cleaner water has a low BOD.

How does the greenhouse effect cause global warming?

Greenhouse gases such as carbon dioxide and methane in the atmosphere trap some of the heat that would otherwise escape to space, keeping the Earth warm enough for life. When human activities release extra greenhouse gases, more heat is trapped, and the average global temperature rises. This is global warming, which changes climates and sea levels.