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O-Level Climate Change (Topic 3.2)

natural variability, human causes, and impacts on natural and human systems

What the syllabus expects

• Past climates show episodes of cooling and warming across geological time, evidenced by oxygen-isotope readings and seafloor sediment data.
  Scope: The natural variability of climate
• Shifting climate zones are signalled by temperature and shown by the expansion and contraction of the main climatic belts.
  Scope: The natural variability of climate
• Natural processes drive climate variability, including changes in Earth's orbit and tilt angle and the occurrence of sunspots and large-scale volcanic eruptions.
  Scope: The natural variability of climate
• Population growth and industrialisation have changed the amount of greenhouse gases including carbon dioxide, methane and nitrous oxide, and recent data show each decade warmer than any before it since 1850.
  Scope: How human factors contribute to climate change
• The greenhouse effect is a natural process that keeps Earth habitable, working through the absorption of shortwave radiation and the emission of longwave radiation.
  Scope: How human factors contribute to climate change
• The enhanced greenhouse effect is driven by the burning of fossil fuels and by changes in land use.
  Scope: How human factors contribute to climate change
• Climate change affects natural systems by raising ocean surface temperatures and altering ocean circulations, and by raising atmospheric temperatures and changing precipitation over land.
  Scope: How climate change may affect natural systems
• In aquatic ecosystems it endangers coral reefs and disrupts marine food webs, and it drives ocean acidification.
  Scope: How climate change may affect natural systems
• In terrestrial ecosystems it threatens plant and animal life and brings more extreme weather such as droughts and excessive rainfall.
  Scope: How climate change may affect natural systems
• Its effect on human systems is geographically uneven because climate variables and local economic and social factors differ, and the impacts are interlinked, cascading from natural systems to people.
  Scope: How climate change may affect human systems
• Direct impacts on human systems come via extreme weather events such as heat waves, droughts, floods, cyclones and wildfires.
  Scope: How climate change may affect human systems
• Indirect impacts affect provisioning services like food production and regulating services like disease regulation, and alter cultural services through the melting of arctic ice and the degradation of natural landscapes.
  Scope: How climate change may affect human systems

How it's examined

About 5% of the past-paper style questions in Rae's bank for this subject sit in this topic.

More O-Level Geography topics

Thinking Geographically (Topic 1.1) · Sustainable Development (Topic 1.2) · Geographical Methods (Topic 1.3) · Tourism Activity (Topic 2.1) · Tourism Development (Topic 2.2) · Sustainable Tourism Development (Topic 2.3) · all of O-Level Geography