Tackling climate change (5.20, 5.21, 5.22)
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Conclusions about climate change can differ because evidence can be interpreted differently, or because different datasets, assumptions and climate models are used.
There is a broad scientific consensus that increasing greenhouse gas emissions from human activities are the main cause of recent global warming. However, some individuals disagree.
When assessing evidence, consider:
- Quality. Does it use sufficient, reliable data?
- Consensus. Is it supported by multiple independent, peer-reviewed studies?
- Statistics. Are the results statistically significant?
- Bias. Could financial, political or personal interests influence the conclusions?
Scientific conclusions should be based on peer-reviewed evidence, not opinion.
The carbon cycle describes the movement of carbon between the atmosphere, living organisms, oceans and rocks.
Carbon is removed from the atmosphere by photosynthesis, which fixes into organic molecules. Carbon returns to the atmosphere through respiration, decomposition and combustion of biomass and fossil fuels. Carbon is also exchanged between the atmosphere and oceans and can be stored long-term in fossil fuels and carbonate rocks.
Knowledge of the carbon cycle can be applied to reduce atmospheric carbon dioxide () by increasing carbon storage (carbon sequestration) or reducing carbon emissions.
Methods to reduce atmospheric include:
- Reforestation – trees remove by photosynthesis and store carbon in biomass and soils.
- Protecting forests and peatlands – this prevents stored carbon from being released through deforestation or decomposition.
- Carbon capture and storage – from power stations and industry is captured and stored underground rather than entering the atmosphere.
- Reducing fossil fuel use – this decreases the transfer of carbon from long-term geological stores to the atmosphere.
These methods help restore the balance between carbon released and carbon removed from the atmosphere.
Sustainable resources are managed so they can be used without being depleted, ensuring they remain available for future generations.
Sustainable management helps meet human demands for food, fuel and materials while conserving natural habitats.
Reforestation is the planting of trees to restore forests lost to deforestation.
Trees remove atmospheric by photosynthesis and store carbon in biomass, helping to reduce the enhanced greenhouse effect. Reforestation also restores habitats, increases biodiversity, reduces soil erosion and improves water retention.
Although land is required for agriculture and development, reforestation helps balance human needs with environmental conservation.
Biofuels are fuels produced from recently living biomass, such as crops or plant waste.
As plants grow, they remove from the atmosphere by photosynthesis. Burning biofuels releases this , so they can be nearly carbon-neutral if new crops are continually grown.
Advantages of biofuels:
- Renewable resource.
- Reduces dependence on fossil fuels.
Limitations of biofuels:
- Uses agricultural land.
- May compete with food production.
- Habitat destruction may reduce biodiversity.