Climate Change: Impacts & Mitigation (AQA GCSE Combined Science: Synergy: Life & Environmental Sciences): Revision Note

What are the effects of climate change?

• Increasing levels of greenhouse gases are causing the average temperature of the Earth to rise, leading to climate change

• Climate change is a long term shift in worldwide weather patterns and conditions

1. Rising sea levels

• The melting of polar ice caps and glaciers is causing sea levels to rise

• This leads to destructive coastal erosion, flooding of wetlands and the destruction of habitats for birds, fish and plants

• Low-lying cities face increased flooding and the permanent loss of usable land

• Rising sea levels also cause increased soil salinity, damaging agricultural land

2. Loss of habitats and biodiversity

• Flooding, temperature changes and shifting ecosystems destroy habitats for wildlife

• As habitats are lost, populations of plants and animals decline, reducing biodiversity

• Some species face local extinction as the conditions they depend on disappear

3. Changes in species distribution

• As temperatures rise, species are forced to move to cooler regions or higher altitudes

• Species that cannot adapt or migrate fast enough face population decline or extinction

• This can disrupt food chains and ecosystems as predator-prey relationships change

4. Changes to weather extremes

• The intensity of storms and hurricanes is increasing as warmer ocean surfaces put more moisture into the atmosphere

• Extreme heat waves are becoming more frequent, causing loss of life and damage to ecosystems and infrastructure

5. Changes in rainfall

• Climate change is altering the amount, timing and distribution of rainfall across the globe

• Some regions experience prolonged droughts leading to crop failure and water shortages

• Others face increasingly intense and unpredictable rainfall, causing flooding and erosion

• Lack of reliable freshwater supplies can lead to economic and political instability as regions compete for dwindling resources

6. Temperature and water stress

• Rising temperatures and changing rainfall patterns put both humans and wildlife under increasing stress

• Reduced freshwater availability affects drinking water, sanitation and agriculture in affected regions

7. Changes in food-producing capacity

• Some regions will see reduced agricultural output as drought, heat stress and changing seasons reduce crop yields

• Food production in these areas may be greatly compromised, leading to hardship and food insecurity

• Other regions may temporarily see increased food-producing capacity as temperatures rise

How can the effects of climate change be reduced?

• Mitigation means taking steps to slow climate change by reducing the rate at which greenhouse gases enter the atmosphere.

Using energy more efficiently

• Reducing overall energy demand means fewer fossil fuels need to be burned

• Energy-efficient appliances, insulation and transport all reduce the total amount of CO₂ released

Using renewable energy

• Replacing fossil fuels with renewable sources such as solar, wind, tidal and hydroelectric power reduces CO₂ emissions

• Renewable energy sources do not release greenhouse gases during electricity generation

Recycling

• Reducing waste by recycling decreases the energy needed to manufacture new products

• It also reduces the volume of waste sent to landfill, which reduces methane emissions from decomposing organic material

Protecting forests

• Forests act as carbon stores

  • Trees absorb CO₂ from the atmosphere during photosynthesis

• Stopping deforestation preserves these carbon stores and maintains the rate of CO₂ uptake

• Replanting and regenerating forests actively removes CO₂ from the atmosphere

Protecting other carbon sinks

• Habitats such as peat bogs store large amounts of carbon in organic matter

• If peat bogs are drained, burned or disturbed, the carbon they contain is released as CO₂

• Protecting these habitats prevents stored carbon from being released into the atmosphere

Carbon capture and storage

• Technologies can capture CO₂ produced at power stations before it reaches the atmosphere

• The captured CO₂ is then stored underground or in other long-term storage, reducing overall greenhouse gas emissions