Climate Change

Study Notes

Climate change involves understanding greenhouse gases, their sources, and the science behind global warming. Human activities have intensified the natural greenhouse effect, leading to climate change.

• Greenhouse Gases — gases in the atmosphere that absorb infrared radiation emitted from the Earth's surface.
  Example: Carbon dioxide (CO₂), methane (CH₄), and water vapour (H₂O) are key greenhouse gases.
• Fossil Fuel Combustion — the burning of coal, oil, and natural gas, releasing CO₂ and water vapour.
  Example: Used in electricity generation and transportation.
• Agricultural Sources of Methane — methane produced from rice cultivation and livestock digestion.
  Example: Rice paddies and cattle farming.
• Waste and Landfill Emissions — methane emissions from decomposing organic waste in landfills.
  Example: Anaerobic conditions in landfills lead to methane production.
• Natural Greenhouse Effect — the process by which greenhouse gases trap heat, keeping Earth warm enough to support life.
  Example: Without it, Earth would be 33°C cooler.
• Enhanced Greenhouse Effect — increased greenhouse gas concentrations trap more heat, causing global warming.
  Example: Human activities have increased CO₂ levels, enhancing this effect.
• Climate Models — computer simulations used to predict future climate changes.
  Example: Models consider variables like greenhouse gas concentrations and ocean currents.
• Climate Feedback Mechanisms — processes that can amplify or dampen climate change.
  Example: Ice-albedo feedback where melting ice reduces reflectivity, causing further warming.

Exam Tips

Key Definitions to Remember

• Greenhouse gases
• Fossil fuel combustion
• Enhanced greenhouse effect

Common Confusions

• Difference between natural and enhanced greenhouse effects
• Misunderstanding the role of water vapour as a greenhouse gas

Typical Exam Questions

• What are greenhouse gases?
  Gases that absorb infrared radiation, such as CO₂, CH₄, and H₂O.
• How does fossil fuel combustion contribute to climate change?
  It releases CO₂ and water vapour, increasing greenhouse gas concentrations.
• What is the enhanced greenhouse effect?
  The increase in Earth's temperature due to higher greenhouse gas levels from human activities.

What Examiners Usually Test

• Understanding of greenhouse gas sources and effects
• Ability to explain the natural vs. enhanced greenhouse effect
• Knowledge of climate feedback mechanisms and their impact