Climate change and energy production
Domain 8 tests climate change evidence, impacts, mitigation and adaptation, and energy production choices. Expect calculations of emissions and evaluation of renewables, nuclear and fossil fuels.
Core rules
- Climate change mitigation reduces causes (emissions, deforestation); adaptation reduces vulnerability to impacts (sea walls, drought-resistant crops, early warning).
- Greenhouse gases differ in radiative forcing and residence time; CO₂ is long-lived, methane is potent but shorter-lived.
- Energy sources vary in carbon intensity, energy density, dispatchability and land use. Renewables are not impact-free.
- Capacity factor is actual output divided by maximum possible output; it affects the real cost and emissions of a plant.
- Feedbacks can amplify (permafrost thaw, ice-albedo) or damp (enhanced weathering) warming.
Worked example
A 1 GW coal plant runs at 50% capacity for 8,760 hours per year and emits 0.9 t CO₂ per MWh. Annual output = 1,000 MW × 0.50 × 8,760 h = 4,380,000 MWh. Emissions = 4,380,000 × 0.9 = 3,942,000 t CO₂ ≈ 3.94 Mt CO₂. Reasoning: capacity factor converts nameplate capacity into actual generation; emissions scale with MWh, not just MW. A 1 GW wind farm at 35% capacity would generate 3,066,000 MWh, avoiding emissions only when it displaces fossil generation.
Traps
- Mixing mitigation and adaptation.
- Assuming a renewable plant has zero emissions; manufacturing, land use and backup matter.
- Confusing MW (power) with MWh (energy).
- Treating climate and weather as the same; a cold spell does not disprove a warming trend.
- Ignoring that nuclear has low carbon emissions but waste and cost issues.