Global climate change: discuss the scale, risk and environmental implications of global climate change.

The idea

Discussing global climate change means considering how large its effects are, how likely and serious the risks are, and what the consequences are for the environment. Scale refers to the size and reach of change: it is global, long-term and affects atmosphere, oceans, ice, land and living things. Risk combines the probability of a harmful outcome with its severity; for example, a small rise in sea level may be manageable in some places but catastrophic for low-lying islands. Environmental implications include loss of biodiversity, altered habitats, ocean acidification, disrupted food chains and changes to water and nutrient cycles. A good discussion weighs evidence, recognises uncertainty in future projections, and considers both environmental and human consequences.

What earns the marks

• Scale: climate change is global and long-term, affecting the atmosphere, oceans, ice sheets, land and ecosystems worldwide.
• Risk: risk depends on both the likelihood of a hazard and the seriousness of its consequences, so the same change can pose different risks in different places.
• Environmental implications: loss of biodiversity, habitat change, ocean acidification, disrupted food chains and altered water and nutrient cycles.
• Human and economic implications: threats to food security, water supply, coastal settlements, health and infrastructure.
• Uncertainty and evidence: projections vary with future emission scenarios, so discussion should acknowledge ranges and confidence rather than treating all outcomes as certain.
• Mitigation and adaptation: reducing emissions lowers future risk, while adaptation manages effects that are already unavoidable.

Common mistakes and how to put them right

• Treating 'scale' as only geographical size and ignoring timescale.

  Put it right: Scale includes both spatial extent and the long duration of change.

• Confusing risk with hazard.

  Put it right: Risk is the chance of harm combined with how serious that harm would be, not simply the existence of a hazard.

• Assuming all environmental effects are reversible.

  Put it right: Some effects, such as species extinction, are permanent on human timescales.

Exam tips

• Use the command word 'discuss' to present balanced points, including both evidence and uncertainty.
• Structure your answer around the three prompts: scale, risk and environmental implications, so every part is addressed.
• Support points with specific examples, such as low-lying islands for sea-level risk or coral reefs for ocean acidification.
• Use comparative language such as 'greater risk', 'more severe' and 'less certain' to show judgement rather than listing facts.