VCE Geography Unit 3 focuses on two processes of land cover change: melting glaciers and ice sheets and deforestation. Understanding where each process is occurring globally is essential for mapping, case study selection and exam responses.
Glacier and ice sheet loss is occurring across all glaciated regions, but at different rates:
Polar ice sheets
- Greenland: losing an average of 280 billion tonnes of ice per year (2002–2019 GRACE data). Losses are concentrated in outlet glaciers on the west and south coasts (Jakobshavn, Helheim, Kangerlussuaq glaciers)
- Antarctica: overall loss of ~150 billion tonnes/year, but with strong regional variation. The West Antarctic Ice Sheet (WAIS) — particularly the Amundsen Sea sector (Thwaites, Pine Island glaciers) — is the most vulnerable. East Antarctica has shown net gains in some areas due to increased snowfall
Mountain glaciers (by region)
| Region | Key Examples | Status |
|---|---|---|
| European Alps | Mer de Glace (France), Aletsch (Switzerland) | Lost ~50% of volume since 1900 |
| Himalayas/Hindu Kush | Gangotri, Siachen | Retreating at 22 m/year average |
| Andes | Chacaltaya (Bolivia), Quelccaya (Peru) | Chacaltaya disappeared 2009 |
| Alaska/Yukon | Columbia Glacier, Malaspina | Among fastest-retreating globally |
| New Zealand | Franz Josef, Fox | Significant retreat in 20th century |
| Arctic (Svalbard, Iceland) | Vatnajökull, Langjökull | Iceland losing ~11 billion tonnes/year |
| Caucasus | Mt Elbrus glaciers | ~50% area loss since 1960 |
| Africa | Rwenzori, Mt Kilimanjaro | Kilimanjaro ~85% ice loss since 1912 |
The greatest total ice loss by volume is from the Greenland Ice Sheet and the Alaskan/Canadian mountain glaciers.
Deforestation — the permanent removal of forest cover — is concentrated in tropical regions, though temperate deforestation continues in some areas.
Tropical deforestation hotspots
| Region | Primary Drivers | Annual Loss Estimate |
|---|---|---|
| Amazon Basin (Brazil, Peru, Bolivia) | Cattle ranching, soy, infrastructure | ~1.5–2 million ha/year (2020s) |
| Congo Basin (DRC, Cameroon, Gabon) | Subsistence agriculture, logging, charcoal | ~450,000 ha/year |
| Southeast Asia (Indonesia, Malaysia, Myanmar) | Palm oil, pulp/paper, smallholder farming | ~700,000 ha/year (declining post-2015 moratoriums) |
| Central America | Cattle, coffee, urban expansion | Significant but declining |
| Cerrado (Brazil) | Soy expansion, agribusiness | Now exceeds Amazon loss in some years |
Why tropical regions?
- Population pressure and poverty drive subsistence clearing
- Commercial agriculture finds fertile (if fragile) soils
- Weak governance and corruption reduce enforcement
- Road construction opens previously inaccessible forest
- Global commodity demand (soy, palm oil, beef, timber) provides economic incentive
Temperate deforestation: Less common today; most temperate forests were cleared historically (e.g., 80% of Europe’s forests cleared pre-industrial). Contemporary loss occurs in parts of Russia (illegal logging), parts of the US Pacific Northwest, and some South American temperate zones.
Both processes show clear spatial clustering:
- Glacier loss is concentrated at high latitudes and high altitudes — the poles, the world’s major mountain ranges, and the Arctic rim
- Deforestation is concentrated in the equatorial tropics, particularly where forest meets agricultural frontier
KEY TAKEAWAY: Glacier retreat is a global phenomenon but is most severe in the Arctic, Greenland, and mountain glaciers of South Asia and the Americas. Deforestation is overwhelmingly concentrated in the tropical belt, led by Brazil, Indonesia and the Democratic Republic of Congo.
VCAA FOCUS: Be able to describe and explain the global distribution of both processes, using correct geographic vocabulary (latitude, altitude, biome, region) and linking distribution to causes such as temperature rise or agricultural expansion.
EXAM TIP: VCAA may show you a map and ask you to describe the distribution. Structure your answer: global pattern first (“concentrated in…”), then regional specifics, then an explanatory link.
