Natural Resources: Revision Notes

Condensed for the final weeks. For the full explanation, use the Natural Resources study guide.

Classification

• Renewable — replenishes naturally within a human timescale: biofuels (bioethanol, biomass, biogas, wood), geothermal, HEP, tidal, wave, solar, wind.
• Non-renewable — fixed stock, consumed faster than formed: coal, oil, gas, mineral ores.
• Sustainable ≠ renewable. A renewable resource used faster than it regenerates is being used unsustainably — a forest felled faster than it regrows still collapses.

Sustainable use = meeting present needs without preventing future generations from meeting theirs. This definition applies equally to a renewable resource, a non-renewable one, and to water — the concept is about the rate and manner of use, not the type of resource itself.

Fossil fuels — balance sheet

Advantages	Disadvantages
High energy density	CO₂ → enhanced greenhouse effect
Reliable, continuous output	SO₂ and NOₓ → acid rain
Existing infrastructure	Particulates harm health
Relatively cheap now	Finite and unevenly distributed
	Land damage from extraction; oil spills

Renewable sources compared

Source	Strength	Limitation
Solar	No fuel cost, no emissions in use	Intermittent, needs storage, large area
Wind	Land below still usable	Intermittent, visual and noise objections
HEP	Reliable, long-lived, flood control	Dam displaces people/habitat, silting, high cost
Geothermal	Continuous, small footprint	Electricity generation only viable in tectonically active areas – heat pumps for heating work anywhere
Biofuels (bioethanol, biomass, biogas, wood)	Uses waste, can be carbon-neutral	Combustion pollutants, competes with food for land

Rocks, ores and minerals (1.1–1.3)

Formation: igneous (granite, basalt) — cooling/solidifying magma or lava. Sedimentary (limestone, sandstone, shale) — eroded particles compacted/cemented in layers; commonly contain fossils. Metamorphic (marble from limestone, slate from shale) — existing rock altered by heat/pressure; fossils don’t usually survive this, though slate can rarely preserve distorted ones. Rock cycle (weathering, erosion, transportation, sedimentation, compaction, cementation, crystallisation, deposition) branches — it isn’t one fixed loop through all three types. Permeability: most sedimentary rocks (limestone, sandstone) are permeable; igneous, metamorphic and shale are impermeable.

Extraction: an ore is rock containing minerals and metals. Three methods — surface (opencast, open-pit, open-cut, strip), subsurface (deep/shaft), biological (phytomining, bioleaching). Factors in the decision: exploration, geology, accessibility/terrain, ore grade, climate, environmental impact assessment, supply/demand, cost/profit.

Sustainable management: a finite resource is used up faster than it’s replaced. Strategies: reduce and reuse; recycling; increased extraction efficiency; avoiding depletion; legislation/enforcement; alternative materials.

Water supply, demand and scarcity are Topic 3 (Water) content, not this topic — see the Water revision notes.

The management framework

Use less (efficiency, conservation) · Use again (reuse, recycle) · Substitute (renewables) · Restore (replanting, rehabilitation, protected areas)

Enabled by legislation, international agreements, education and pricing.

Why fossil fuel dependence persists

A question asking why a country continues to rely on fossil fuels despite known environmental costs is really asking for economic and political, not just technical, reasons:

• Sunk infrastructure — power stations, refineries and distribution networks represent an enormous existing investment, costly to abandon before the end of their working life.
• Cost and reliability — fossil fuels remain cheaper and more reliable for baseload generation in many countries; cheap energy supports industrial competitiveness and keeps consumer bills low.
• Employment and government revenue — mining and oil regions depend on the industry, so closure carries a heavy political and social cost.
• Build-out limits — renewable capacity and storage technology cannot be built quickly enough to fully replace demand, making a transition period unavoidable regardless of intent.

Exam traps

• Renewable and sustainable are not synonyms — the single most examined distinction here.
• Solar and wind produce no emissions in use — manufacturing still has an impact.
• HEP is not impact-free; dams displace communities and ecosystems.
• Fresh water is renewable yet can still be depleted.
• 0680’s own command-word table has no “evaluate” entry — the syllabus’s own stem for this is “discuss the benefits and limitations,” so answer that, not a generic “evaluate.”
• Explaining fossil fuel dependence only in technical terms (reliability, energy density) without the economic and political reasons — sunk infrastructure, employment, and the pace at which renewable capacity can realistically be built.
• Defining a mineral by whether it is mined, rather than by its composition and crystalline structure.
• Drawing the rock cycle as one single loop through the three rock types instead of a branching process.

Self-test

1. Give an example of a renewable resource being used unsustainably.
2. Why might a sunny country still rely on fossil fuels?
3. Name the three rock/ore extraction methods, including both biological-extraction processes.
4. State two disadvantages of hydroelectric power.
5. Define sustainable use.
6. Define an ore, and explain why it differs from a mineral.
7. Give two economic or political reasons a country might continue relying on fossil fuels.

Answers: 1. A forest felled faster than it regrows, or fish stocks caught faster than they breed. 2. Solar is intermittent and needs storage or back-up; capital costs are high; existing grid infrastructure is built for fossil fuels; large land area is required. 3. Surface extraction (opencast/open-pit/open-cut/strip mining), subsurface extraction (deep/shaft mining), and biological extraction (phytomining and bioleaching). 4. Displacement of people and habitats by the reservoir; high capital cost; silting reducing capacity; disruption to fish migration. 5. Meeting the needs of the present without compromising the ability of future generations to meet their own needs. 6. An ore is rock containing minerals and metals; a mineral is a naturally occurring solid with a definite chemical composition and crystalline structure, whether or not it is mined — an ore is a rock category defined by extractable content, a mineral is a substance defined by its physical/chemical structure. 7. Any two: sunk investment in existing infrastructure, cheaper and more reliable baseload generation, employment and government revenue from the industry, or renewable capacity being unable to be built quickly enough to replace demand.

For the full worked explanation with additional detail, see the Natural Resources study guide; for exam-style questions with full mark schemes, see the Natural Resources practice questions.