In simple terms
A friendly intro before the formal notes — no formulas yet.
Our Planet's Energy Bill
Our global energy choices have put the Earth's climate system into 'overdraft'. We'll explore how our reliance on certain energy sources is raising the planet's temperature and what we can do to balance the books.
Imagine your personal health. Relying on fossil fuels is like a diet of only fast food and sugary drinks; it gives you a quick energy boost but leads to long-term health problems like a high fever (global warming). Switching to renewable energy is like adopting a balanced diet and exercise plan; it's a sustainable way to stay healthy and avoid a crisis.
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Connect our daily energy use (electricity, transport) to specific sources like coal, oil, gas, and renewables.
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Understand how burning fossil fuels releases greenhouse gases, trapping more heat in the atmosphere—the enhanced greenhouse effect.
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Examine the consequences: rising sea levels, more extreme weather, and threats to food and water security.
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Compare and evaluate solutions, from global agreements and carbon taxes (mitigation) to building sea walls (adaptation).
Explore the concept
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Full topic notes
Formal explanation with the rigour you need for the exam.
Energy Choices and Greenhouse Gas Emissions
The global energy system is dominated by three main fossil fuels: coal, oil, and natural gas. When these fuels are combusted to release energy, they also release greenhouse gases (GHGs) into the atmosphere. The most significant of these is carbon dioxide (), but methane () and nitrous oxide () are also major contributors. While the natural greenhouse effect is essential for life, the additional GHGs from human (anthropogenic) activities have intensified this effect, leading to global warming and climate change.
Fossil Fuels: Account for over 80% of global energy consumption and are the largest source of anthropogenic GHG emissions.
Electricity Generation: Coal-fired power plants are a major source of .
Transport: Cars, lorries, ships, and aeroplanes predominantly run on oil-based fuels like petrol and diesel.
Industry & Agriculture: Industrial processes and agricultural practices (e.g., livestock farming, rice paddies, fertiliser use) release significant amounts of and .
Deforestation: Clearing forests reduces the planet's capacity to absorb through photosynthesis.
Impacts of Climate Change
The consequences of a warming planet are far-reaching and interconnected, affecting both natural ecosystems and human societies. These impacts are not distributed evenly; low-income nations and vulnerable communities often bear the brunt of the effects, despite having contributed least to the problem. Key impacts include rising sea levels from thermal expansion of water and melting ice caps, increased frequency and intensity of extreme weather events like hurricanes and heatwaves, disruption to agriculture and food security, and threats to biodiversity as habitats change faster than species can adapt.
Responding to Climate Change: Mitigation and Adaptation
Human responses to climate change fall into two main categories. Mitigation focuses on tackling the causes of climate change by reducing or preventing GHG emissions. It is a global-scale problem requiring global-scale solutions. Adaptation involves adjusting our societies and ecosystems to cope with the unavoidable impacts of climate change that are already happening or are expected in the future. Adaptation is often more local or regional in its implementation. A comprehensive climate strategy requires both mitigation to prevent the unmanageable and adaptation to manage the unavoidable.
Mitigation Examples: Reducing energy consumption, switching to renewable energy sources (solar, wind), carbon capture and storage (CCS), afforestation, promoting public transport, and implementing carbon taxes or trading schemes.
Adaptation Examples: Building sea walls and flood defences, developing drought-resistant crops, managing water resources more effectively, creating early warning systems for extreme weather, and planned relocation of vulnerable communities.
Synergy: Some strategies can have both mitigation and adaptation benefits. For example, planting mangrove forests can sequester carbon (mitigation) and protect coastlines from storm surges (adaptation).
In Paper 2, when asked to 'evaluate' or 'discuss' climate change strategies, you must provide a balanced argument. This means outlining both the strengths and weaknesses or arguments for and against a particular approach. Use specific, named examples. For instance, instead of just 'renewable energy', discuss 'the Hornsea Wind Farm project in the UK' or 'the Noor Ouarzazate Solar Complex in Morocco'. A concluding statement that summarises your judgement is essential for top marks.
Worked examples
See the formulas applied — reveal one step at a time, like the exam.
A UK household consumes 3,500 kWh of electricity per year. The national grid has an emission factor of 0.233 kg e per kWh. If the household installs solar panels that generate 3,000 kWh per year (with a lifecycle emission factor of 0.045 kg e/kWh) and imports the remaining 500 kWh from the grid, calculate the annual reduction in carbon dioxide equivalent (e) emissions. [3 marks]
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Calculate initial emissions:
Evaluate the use of carbon taxes as a strategy for mitigating climate change. [9 marks]
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A carbon tax is a market-based mitigation strategy that puts a direct price on carbon dioxide emissions, aiming to reduce them by making polluting activities more expensive. Its effectiveness can be evaluated by considering its strengths and weaknesses.
How it all connects
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Tap a linked idea to see how it connects back to the main topic — that connection is what examiners reward.
Glossary
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Quick check
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Revision flashcards
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Mitigation (Climate Change)
Strategies that aim to reduce or prevent the emission of greenhouse gases, tackling the root cause of climate change. Examples: switching to renewable energy, improving energy efficiency, afforestation.
Key takeaways
Review these before you close the topic — retrieval beats re-reading.
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Fossil Fuels: Account for over 80% of global energy consumption and are the largest source of anthropogenic GHG emissions.
- ✓
Electricity Generation: Coal-fired power plants are a major source of .
- ✓
Transport: Cars, lorries, ships, and aeroplanes predominantly run on oil-based fuels like petrol and diesel.
- ✓
Industry & Agriculture: Industrial processes and agricultural practices (e.g., livestock farming, rice paddies, fertiliser use) release significant amounts of and .
- ✓
Deforestation: Clearing forests reduces the planet's capacity to absorb through photosynthesis.
Practice — then mark it
The whole point: a real Cambridge question, marked mark-by-mark.
Test Your Knowledge on Climate Change & Energy
Test Your Knowledge on Climate Change & Energy
Extra simulations & links
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Frequently asked
Checkpoint
One marked question is worth ten re-reads — close the loop before you move on.
Reading it isn’t knowing it — prove it.
Before you move on: do Test Your Knowledge on Climate Change & Energy on paper, snap a photo, and get examiner-style feedback on exactly where you win and lose marks.