Decarbonization of the economy means reducing or ending the use of energy sources that produce carbon dioxide emissions and replacing them with low-carbon or renewable alternatives. In IB ESS subtopic 6.3, it is a climate change mitigation strategy studied at both SL and HL.
How Decarbonization Works
Fossil fuels such as coal, oil and natural gas supply energy to electricity generation, transport, industry and buildings. Their combustion transfers carbon from long-term geological stores into the atmosphere as carbon dioxide, enhancing the greenhouse effect.
Decarbonization changes these energy flows by reducing fossil-fuel demand and replacing high-carbon technologies. It therefore addresses a cause of climate change rather than merely managing its consequences.
| Decarbonization strategy | Mechanism and example |
|---|---|
| Renewable electricity | Replaces coal- or gas-fired generation with wind, solar or hydroelectric power. Denmark's expansion of wind power illustrates this approach. |
| Electrification | Replaces direct fossil-fuel use with electricity, for example electric vehicles and heat pumps. Its effectiveness depends on how the electricity is generated. |
| Energy efficiency | Reduces the energy required for the same service through insulation, efficient appliances and industrial improvements. |
| Low-carbon industry | Uses technologies such as green hydrogen, material recycling and carbon capture where direct electrification is difficult. |
| Reduced demand | Changes transport, consumption and urban planning to lower total energy use. |
A common misconception is that decarbonization means removing all carbon from the economy. Carbon remains essential in food, organisms and materials; the goal is primarily to reduce anthropogenic carbon dioxide emissions from energy and production systems.
Decarbonization also has social and economic consequences. Workers and regions dependent on fossil-fuel industries may require retraining and investment, so a just transition should distribute costs and benefits equitably.
Exam Technique
For an explain question, define decarbonization and show how replacing fossil fuels reduces emissions. For evaluate, consider effectiveness, cost, energy security, technological limitations and environmental justice, use a named example, and reach a supported conclusion. Do not confuse decarbonization with adaptation, which reduces the impacts of climate change rather than its causes.