Gases in the atmosphere absorb outgoing longwave radiation and warm the Earth.
Enhanced greenhouse effect
Extra warming caused by human greenhouse gas emissions.
Albedo
The proportion of incoming solar radiation a surface reflects.
Positive feedback
A change that amplifies the original change (e.g. melting ice lowers albedo).
Carbon sink
A store that absorbs more carbon than it releases (oceans, forests).
Energy balance: incoming shortwave solar radiation; outgoing longwave radiation. Greenhouse gases (CO₂, CH₄, N₂O, water vapour) trap part of the outgoing energy.
The full notes, worked example, interactive diagram and check questions for this subtopic are in the app.
Exam tip: Draw a quick feedback loop diagram in essays: examiners reward clear process explanations.
2.2Consequences of global climate change
Key terms
Vulnerability
How likely people or places are to be harmed, depending on exposure, sensitivity and capacity to cope.
Resilience
The ability to absorb a shock and recover.
Sea-level rise
Caused by thermal expansion of water and melting land ice.
Climate refugee
A person displaced by climate impacts (not a legal refugee category).
Physical impacts: sea-level rise, more intense heatwaves and heavy rainfall, droughts, glacier retreat, coral bleaching, shifting biomes.
The full notes, worked example and check questions for this subtopic are in the app.
Exam tip: Structure vulnerability answers with exposure / sensitivity / capacity: it shows conceptual understanding.
2.3Responding to global climate change
Key terms
Mitigation
Reducing emissions or increasing sinks to limit climate change.
Adaptation
Adjusting to actual or expected impacts.
Nationally determined contribution (NDC)
Each country's own pledge under the Paris Agreement.
Carbon trading
A cap on emissions with tradable permits (e.g. EU ETS, 2005).
Geoengineering
Large-scale deliberate intervention in the climate system.
Global: UNFCCC (1992), Kyoto Protocol (1997, binding targets for richer countries), Paris Agreement (2015): keep warming well below 2 °C and pursue 1.5 °C; countries set NDCs, reviewed every five years.
The full notes, worked example and check questions for this subtopic are in the app.
Exam tip: In essays, compare responses at different scales (global, national, local) and judge their effectiveness.