Year 8 Geography – Full Revision Notes

Exam Overview

Year 8 final exam
- Worth $50\%$ of overall grade
- Total of $66$ marks
- Questions arranged chronologically (Terms 1 ➜ 4)
- Mix of skills: definition, explanation, application, and evaluation

Term 1 – Weather & Climate

1. Difference Between Weather & Climate

Weather
- State of the atmosphere at a specific time/place
- Highly local; changes hourly/daily
- Elements: temperature, precipitation, wind, cloud cover, humidity
Climate
- Average weather over a long period (≈ $30$ yrs)
- Describes “usual” conditions

2. Air Pressure & Its Influence

Air pressure = force exerted by the weight of air above
- Rising air ⇒ pressure falls (low pressure)
- Sinking air ⇒ pressure rises (high pressure)
Keywords
- High pressure = sinking air toward ground
- Low pressure = rising air from surface

3. High-Pressure Weather Patterns

Summer anticyclones
- Clear skies ➜ warm, sunny days
- Nighttime heat loss ➜ rapid temperature drop, dew/mist, thunderstorm risk in heat waves
Winter anticyclones
- Clear, cold, bright days; no cloud “blanket”
- Rapid night cooling ➜ frost on surfaces, fog (condensation on dust)
- Hazardous driving due to reduced visibility

4. Elements of Weather (5)

Temperature, Precipitation, Wind, Cloud cover, Humidity

5. Types of Rainfall

Convectional
- Stage 1 – Sun heats ground; warm air rises
- Stage 2 – Rising air cools; water vapour condenses
- Stage 3 – Large cumulonimbus clouds form
- Stage 4 – Heavy thunderstorms (lightning from electrical charge)
Frontal
- Warm air meets cold front; forced to rise
- Cooling/condensation at boundary ➜ cloud & rain along front
Relief (Orographic)
- Moist air forced over high land
- Cools/condenses on windward slope ➜ precipitation
- Descending air on leeward side warms/drys (rain-shadow)

6. Tropical Storms

Form over oceans >27^{\circ}\text{C}, between $5^{\circ}$ – $15^{\circ}$ N/S
General tracks : westward due to trade winds, then pole-ward curve
Absent within $5^{\circ}$ of equator (insufficient Coriolis force)

Formation Sequence

Strong surface evaporation; warm, moist air rises
Cooling ➜ condensation ➜ towering cumulonimbus; latent heat release fuels uplift
Multiple storms merge; system begins to rotate (Coriolis)
Eye forms (subsiding dry air); average wind $\ge 120\text{ km h}^{-1}$ ⇒ officially a tropical storm
Landfall ➜ energy source cut; storm weakens

Typhoon Haiyan (Philippines 2013) – Effects

Primary (P)
- $\approx6{,}300$ deaths (mainly storm surge)
- >60{,}0000 displaced; $40{,}000$ homes damaged; $90\%$ of Tacloban destroyed
- $30{,}000$ fishing boats lost; airport terminal damaged; crops & power lines destroyed
Secondary (S)
- $6$ million lost income; jobs, schools, hospitals lost
- Water/food shortages ➜ disease outbreaks
- Landslides, blocked roads hindered aid; ferry/air services disrupted for weeks

Term 2 – Climate Change

1. Greenhouse Gases (GHGs)

Natural & anthropogenic: $\text{H}2\text{O}$ , $\text{CO}2$ , $\text{CH}4$ , $\text{N}2\text{O}$ , halogenated gases (CFCs/HFCs)

2. The Greenhouse Effect (Natural)

Solar radiation passes atmosphere ⇒ Earth surface warms
Surface emits long-wave radiation
GHG layer traps part of this heat, maintaining habitable temperatures

3. Enhanced Greenhouse Effect (Human)

Human activity thickens GHG layer ⇒ more heat retained ⇒ global warming

4. Evidence For Climate Change

Phenology: earlier tree flowering & bird nesting
Glacier Retreat: Arctic ice thickness ↓ $65\%$ since $1975$
Sea-level Rise: $10$ – $20\text{ cm}$ in last century (thermal expansion + meltwater)
Tree Rings: wide rings = warm/wet; narrow = cool/dry; show past variability
Ice Cores: trapped gas bubbles reveal historic $\text{CO}2$ / $\text{CH}4$ ⇒ higher GHG ↔ warmer temp

5. Human Drivers

Fossil Fuels – burning coal, oil, gas for transport/industry/power
- Renewable alternative e.g. solar, wind, hydro (challenge)
Deforestation – releases stored carbon; reduces carbon sink capacity
- Carbon store = reservoir of carbon (vegetation, soil, ocean, atmosphere)
Agriculture – cattle produce $\text{CH}4$ ; fertilisers release $\text{N}2\text{O}$
- Farming sector ≈ $14\%$ of global GHG (exceeds transport)

6. Impacts of Climate Change

Hotter summers & heatwaves; increased drought frequency
Polar ice melt ⇒ sea-level rise; flooding of low-lying states (e.g. Bangladesh)
More intense storms, floods, wildfires
Agricultural stress: crop failure from heat/drought/flood
Ecosystem losses: polar bears (ice), coral bleaching
Climate migration; health risks; disease range expansion (e.g. malaria)

Term 3 – Population Studies

1. Key Demographic Terms

Birth rate = live births per $1000$ people per year
Death rate = deaths per $1000$ people per year
Natural increase
- $\text{Natural increase}=\text{birth rate} - \text{death rate}$
Population distribution = spatial pattern of where people live
Density
- Densely populated = many people per area
- Sparsely populated = few people per area

2. Describing Population Graphs

World population grew slowly to $~1800$ , then exponential rise (Industrial Revolution, medical advances)
By $2020$ , population ≈ $7.8$ billion

3. China’s One-Child Policy

Introduced after 1970s “Later, Longer, Fewer” campaign failed to curb rapid growth
Aims: prevent famine, unemployment, resource shortages

Successes

Estimated $400$ million births averted
Slowed population growth → sufficient jobs & food
Families saved childcare costs; stronger grandparent–grandchild bonds

Failures/Issues

Forced abortions (up to 9 months); state control of reproduction
Gender imbalance: son preference ⇒ female infanticide/orphanages
Ageing population: $4\text{–}2\text{–}1$ problem (one child supports 4 elders)
“Little Emperors” stereotype – spoilt only children
Pressure from “Granny Police” enforcing policy

Term 4 – Biomes & Rainforests

1. Definitions

Ecosystem = interaction of living (biotic) & non-living (abiotic) components
Biome = large-scale ecosystem, e.g. desert, polar, tropical rainforest

2. Vertical Structure of a Tropical Rainforest

Emergent Layer (≈ $40\text{–}50\text{ m}$ )
- Tallest trees; ample sunlight; exposed to wind/rain
- Fauna: eagles, hornbills, bats, butterflies, monkeys
Canopy (main roof)
- Dense continuous layer; leaves with drip tips
- Food-rich ⇒ orangutans, proboscis monkeys, snakes
Under-canopy
- Limited light; large-leaf plants; trunk flowers/fruits
- Animals: red-eyed tree frogs, parakeets, clouded leopards
Ground/Shrub Layer
- Very dark; rapid decay; leaf litter; termites, fungi, centipedes

3. Plant Adaptations

Lianas: woody vines using tree trunks to reach light
Buttress roots: wide surface roots for tall-tree support & nutrient uptake
Drip-tip leaves: channel heavy rain away, preventing leaf damage & directing water to roots

4. Causes of Deforestation

Commercial logging (furniture)
Palm-oil plantations
Mineral extraction (mining)
Road building & population expansion

5. Impacts of Deforestation

Loss of “lungs of the world” ⇒ reduced $\text{O}2$ and $\text{CO}2$ cycling
Broken nutrient cycle ⇒ soil degradation
Biodiversity loss; species extinction (undiscovered species too)
Loss of medicinal plants (potential cancer cures)
Increased hardship for locals (longer wood-collecting journeys)
Economic impacts: ecotourism, sustainable harvesting decline

Final Exam Technique Tips

Use full range of revision resources: Geog 2 textbook, purple exercise book, revision booklet, VLE, PowerPoint
Allocate time effectively; revisit answers for checking/improvement
Note the mark value to gauge answer depth (ideas/points needed)
Avoid bullet points in long-mark questions; write developed paragraphs
Always reference provided maps, graphs, quotes using data/figures
Show compass directions & latitudes when describing distributions (e.g. tropical storms)