The natural and human causes of climate change, its global and local effects, and the strategies used to manage it (AO1, AO2).

What this dot point is asking

CCEA wants you to explain the causes of climate change, distinguishing natural causes from the human activities that are driving recent warming, then to describe its effects on the environment and people, and finally to evaluate the strategies used to respond. The highest marks come from the extended evaluation question, so you need balance: mitigation (reducing the causes) versus adaptation (coping with the effects), and a supported judgement.

The natural causes of climate change

These natural causes explain past ice ages and warm periods, but they are too slow or too small to explain the rapid warming of the last century.

The human causes and the greenhouse effect

The effects of climate change

Group the effects into environmental and human, and use specifics.

• Rising sea levels. Melting ice and the expansion of warming seawater raise sea levels, flooding low-lying coasts and small islands and increasing coastal erosion.
• Melting ice and changing ecosystems. Glaciers and Arctic sea ice shrink; habitats shift or disappear, threatening species such as polar bears, and some plants and animals move to new areas.
• More extreme weather. More frequent and intense droughts, floods, heatwaves and storms damage homes, crops and infrastructure.
• Pressure on water and food. Changing rainfall patterns cause water shortages in some regions and crop failures, threatening food security and forcing migration.

Responding: mitigation and adaptation

The two strategies attack different parts of the problem, and a good evaluation weighs them.

• Mitigation (reducing the causes). Switch to renewable energy (wind, solar, hydro, tidal), improve energy efficiency, plant trees (afforestation), and agree international cuts to emissions, such as the Paris Agreement. Mitigation tackles the root cause but is slow and needs global cooperation.
• Adaptation (coping with the effects). Build sea and flood defences, develop drought-resistant crops, improve water storage and management, and plan cities for heat. Adaptation protects people now but does not stop the warming.

Worked example: the extended evaluation

Common mistakes

Examples in context

Example 1. Why small island nations fear sea-level rise most. Low-lying island states such as the Maldives sit barely above sea level, so even a small rise floods homes, contaminates fresh water with salt, and could make the islands uninhabitable. They contribute almost nothing to global emissions yet face the worst effects, which is why they push hardest for mitigation at climate talks. This unfairness is a strong point in an evaluation answer.

Example 2. The Paris Agreement and its limits. Under the Paris Agreement, countries pledged to limit global warming to well below 2 degrees Celsius by cutting emissions. It shows the value of international cooperation, but progress depends on every country keeping its promise, and some emit far more than they pledge. Using a named agreement, and noting its limits, demonstrates the balanced understanding examiners reward at the top level.

Try this

Q1. Name two greenhouse gases produced by human activity. [2 marks]

• Cue. Carbon dioxide (from burning fossil fuels) and methane (from farming and landfill).

Q2. Give one natural cause of climate change. [1 mark]

• Cue. Changes in solar output, the Earth's orbit, or volcanic eruptions.

Q3. What is the difference between mitigation and adaptation? [2 marks]

• Cue. Mitigation reduces the causes (cutting emissions); adaptation copes with the effects (such as sea defences).