2.1.2 The global energy balance
Content
- Geographic inquiry and concept(s)
- How natural and human processes affect the global energy balance
- Geographic knowledge and understanding
- Changes in the global energy balance, and the role of feedback loops, resulting from: solar radiation variations, including global dimming due to volcanic eruptions
- Changes in the global energy balance, and the role of feedback loops, resulting from: terrestrial albedo changes and feedback loops
- Changes in the global energy balance, and the role of feedback loops, resulting from: methane gas release and feedback loops
- Case study or detailed examples
- Neither required by the syllabus
- Aims of this lesson
- To have knowledge of what a positive and negative feedback loop are.
- To understand how solar radiation and volcanic eruptions can change the global energy balance.
- To have knowledge of how the terrestrial albedo fluctuates and how this creates change to the feedback loops.
- To understand how methane gas is released into the atmosphere and how this impacts the global energy balance.
Base knowledge and understanding
News article
Climate ‘feedback loops’ could worsen global warming by 30%, study finds
Emissions of planet-heating methane and CO2 from natural sources are worsening the climate crisis, paper says
The Guardian · 10 September 2026
Key terms
- Energy balance
- The equilibrium between incoming (shortwave) solar radiation and outgoing (longwave) terrestrial radiation.
- Feedback loops
- Occur when the outputs of a system circulate back and become inputs in a series of cause-and-effect cycles.
- Global dimming
- The decrease in the amount of sunlight reaching the surface of the Earth due to pollution and other particles in the atmosphere. The phenomenon can also occur naturally because of volcanic emissions.
- Methane
- A potent greenhouse gas composed of one carbon atom and four hydrogen atoms. Methane's Global Warming Potential is 86 times greater than carbon dioxide over 20 years and 34 times greater over 100 years.
- Negative feedback
- When a system acts by lessening the effect of the original change and ultimately reversing it.
- Positive feedback
- Occurs within a system where a change causes a snowball effect, continuing or even accelerating the original change.
- Terrestrial albedo changes
- Refer to changes in the reflectivity of the Earth's surface. Albedo is the proportion of solar energy (insolation) that is reflected back into space by a surface. Light-coloured surfaces, such as ice and snow, have a high albedo, meaning they reflect a large proportion of insolation. Dark-coloured surfaces, such as forests and oceans, have a low albedo, meaning they absorb more insolation.
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Review
- Explain how a major volcanic eruption can lead to short-term global cooling. [2]
- Explain two natural factors that can cause variations in the amount of solar radiation reaching the Earth's surface. [4]
- “Variations in the sun's energy output are the most significant natural cause of global temperature fluctuations.” To what extent do you agree with this statement? [10]