12 ATAR Geography Climate Change Stats + factors

General spatial pattern of global temperature

Temperature decreases from the equator towards the poles

Equatorial and tropical mean annual temperatures (0–20° N/S)

25–30°C

Reason equatorial regions are hottest

High solar angle and year-round concentration of insolation

Example tropical locations with high temperatures

Singapore (27°C) and Abuja (26°C)

Average temperatures in subtropical regions (20–35° N/S)

20–25°C

Examples of subtropical locations

Cairo (22°C) and Perth (19°C)

Temperature range in mid-latitudes (35–60° N/S)

5–20°C

Examples of mid-latitude cities

London (11°C) and New York City (13°C)

Temperature range in polar regions (above 60° N/S)

−5°C to −50°C

Examples of polar temperatures

North Pole (−18°C) and South Pole (−49°C)

Three factors modifying global temperature patterns

Ocean currents, altitude, distance from the ocean

Main controls of global rainfall patterns

Latitude and global circulation of air masses

Rainfall in equatorial regions

1500–2500 mm per year

Cause of heavy equatorial rainfall

Intense convectional uplift along the ITCZ

Examples of high rainfall tropical cities

Singapore (2160 mm) and Mumbai (2200 mm)

Latitude of subtropical desert zones

20–35° N/S

Reason subtropical regions are dry

Descending dry air from the Hadley Cell

Example of extremely dry subtropical city

Cairo (20 mm annually)

Rainfall pattern of Perth

Mediterranean climate with 600–700 mm mainly in winter

Rainfall in mid-latitudes

500–1200 mm annually

Examples of mid-latitude rainfall

London (620 mm) and Vancouver (1200 mm)

Rainfall in polar regions

Less than 250 mm annually

Example polar rainfall

South Pole receives about 25 mm

Factors modifying rainfall distribution

Mountain barriers, proximity to oceans, ocean currents

Heat budget definition

Balance between incoming solar radiation and outgoing heat energy

Process that traps heat in the atmosphere

Greenhouse effect

Carbon cycle definition

Movement of carbon between atmosphere, oceans, land and living organisms

Another name for the water cycle

Hydrological cycle

Hydrological cycle describes

The movement of water around Earth systems

Atmospheric circulation definition

Global movement of air redistributing heat around Earth

Three gases released by volcanic eruptions

Carbon dioxide, sulphur dioxide, water vapour

Effect of volcanic aerosols on climate

Scatter solar radiation causing cooling

Particles from volcanoes reflecting sunlight

Ash and dust

Volcanic eruption example influencing climate

Mt Tambora (1815)

Sulphur dioxide released by Tambora

60–80 megatons

Temperature drop caused by Tambora

Up to 3°C

Solar activity cycle length

11 years

Solar activity measured by

Number of sunspots

Solar variability influence on global temperature

Up to 10%

Approximate temperature change from solar variation

About 0.1°C

Transport share of global greenhouse emissions

About 20%

Transport energy from fossil fuels

95%

Aviation share of global CO₂ emissions

About 2%

Shipping share of global greenhouse emissions

About 2%

CO₂ produced by a round-trip flight New York–Europe

About 1.5 tonnes per passenger

Land use and land cover change contribution to emissions

About 10% of global greenhouse emissions

Global warming attributed to LULCC since pre-industrial times

About 0.1°C

Scientific field studying ice cores

Cryology

Where ice cores are drilled

Greenland and Antarctica

What air bubbles in ice cores reveal

Past atmospheric greenhouse gas concentrations

Length of longest ice core (Vostok)

Over 3 km

Climate record length from ice cores

Over 1,200,000 years

Key relationship shown in ice cores

Strong correlation between CO₂ and temperature

Instrumental temperature record definition

Global temperature measurements since 1880

Sources of instrumental temperature data

Weather stations, ships, balloons, satellites

Global temperature rise since 1850–1900 baseline

About 1.2°C

Number of hottest years since 2000

24 of the 25 hottest years

Temperature anomaly in 2024

1.47°C above mid-19th century baseline

Temperature increase in Australia since 1910

About 1.5°C

Natural carbon sequestration definition

Vegetation absorbing and storing carbon dioxide

Effect of land clearing on carbon sinks

Loss of carbon sequestration

Surface property affecting heat absorption

Albedo

Examples of ecosystems cleared for agriculture

Amazon rainforest and Australian temperate grasslands

Greenhouse gas released from thawing permafrost

Methane

Global warming potential of methane

About 30 times stronger than CO₂

Albedo of sea ice

About 60%

Albedo of sea water

About 10%

Two main causes of sea level rise

Glacial melting and thermal expansion

Current global rate of sea level rise

4.5 mm per year

WA coastal erosion example

Seabird

UK coastline eroding about 2 m per year

Holderness Coast

Deltas affected by sea level rise

Nile Delta and Ganges-Brahmaputra Delta

Coral reef experiencing mass bleaching

Great Barrier Reef

Decrease in rainfall in southwest WA

About 20%

Reduction in Perth dam streamflow

About 80%

Main solution used in Perth to address water shortage

Desalination plants

Projected global sea level rise by 2100

0.29–1.1 m

Projected sea level rise for Pacific Islands under RCP 8.5

Up to 1.1 m by 2100

Projected increase in coastal flooding by 2100

Up to 50 times

Projected decline in mangrove forests by 2100

Up to 30%

Projected loss of Great Barrier Reef if temperatures exceed 2°C

About 99%

Climate factor increasing drought risk

Changing rainfall patterns

Process threatening freshwater supplies in coastal cities

Saltwater intrusion

Share of Jakarta’s water from groundwater

About 60%

Projected population of Lagos by 2035

30 million