Climate Change

• What is climate change?

  Climate change refers to long-term shifts in temperature and weather patterns on Earth.
• Name 3 types of evidence for climate change.

  1. Ice cores
  2. Tree rings
  3. Historical records (e.g., harvest dates, paintings)
• How do ice cores provide reliable evidence for climate change?

  • Ice cores contain trapped air bubbles that preserve past atmospheric gases (e.g. CO₂, methane)
  • Scientists can analyse layers of ice, each representing a year, and compare current gas levels to those from hundreds of thousands of years ago.
  • This shows strong links between greenhouse gas concentration and global temperature
• How do tree rings show climate change?

  • Trees grow a new ring each year.
  • In warm, wet years the rings are wider; in colder, drier years they’re narrower.
  • By studying tree rings from living trees and preserved wood, scientists can reconstruct climate patterns over the past 10,000 years
• How do historical sources help identify climate change?

  • Written records (e.g., harvest times, river freeze dates, paintings) can give insight into past climates.
  • For example, “frost fairs” on the River Thames during the Little Ice Age (1300–1870) indicate colder periods.
  • While less scientific, they support instrumental and physical evidence.
• Explain how orbital changes (Milankovitch cycles) affect climate

  • Eccentricity: Earth’s orbit changes from circular to oval every 100,000 years, affecting distance from the sun.

  • Axial tilt: Earth tilts between 21.5°–24.5° every 41,000 years, changing the intensity of seasons.

  • Precession: A wobble in Earth’s rotation every 26,000 years alters seasonal contrasts.

  These cycles affect how much solar radiation Earth receives and can trigger glacial/interglacial periods
• How does solar output influence climate change?

  • The sun’s energy output varies in cycles (e.g., sunspots every 11 years). Periods of low solar output, have been linked to cooler temperatures.
  • However, recent warming cannot be explained by solar output alone
• How do volcanic eruptions cause short-term climate cooling?

  • Large eruptions release ash and sulphur dioxide into the stratosphere.
  • These particles reflect sunlight (global dimming), leading to temporary cooling
• Explain how burning fossil fuels leads to climate change

  •  Burning coal, oil, and gas releases CO₂, a greenhouse gas that traps heat in the atmosphere.
  • This enhances the natural greenhouse effect, leading to global warming. CO₂ emissions from power stations, transport, and industry are major contributors
• How does deforestation contribute to climate change?

  • Trees absorb CO₂ during photosynthesis.
  • When trees are cut down and burned or left to rot, the stored CO₂ is released, increasing atmospheric concentrations and enhancing the greenhouse effect
• How does agriculture increase greenhouse gas emissions?

  • Livestock, especially cattle, release methane through digestion.
  • Rice paddies also emit methane.
  • Fertilisers used in farming release nitrous oxide, a potent greenhouse gas.
  • As global food demand rises, so do emissions
• What are 3 environmental effects of climate change?

  1. Melting ice sheets and glaciers – leading to sea level rise.
  2. More frequent extreme weather – droughts, floods, hurricanes.
  3. Loss of habitats – coral bleaching, species extinction due to shifting climate zones
• What are 3 economic and social effects of climate change?

  1. Reduced crop yields – threatening food security in LICs.
  2. Increased cost of climate-related disasters – rebuilding after floods, fires, etc.
  3. Climate migration – people displaced by sea level rise or drought (e.g., Bangladesh, Tuvalu)
• What is climate change mitigation?

  Mitigation aims to tackle the causes of climate change by reducing or preventing greenhouse gas emissions
• Describe 4 climate change mitigation strategies

  1. Renewable energy – replacing fossil fuels with wind, solar, HEP
  2. Carbon capture – storing CO₂ underground to prevent atmospheric release
  3. Afforestation – planting trees to absorb CO₂.
  4. International agreements – e.g., the Paris Agreement (2015) aims to limit warming to below 2°C.
• What is climate change adaptation?

  Adaptation involves adjusting to the effects of climate change to reduce vulnerability.
•  Describe 3 adaptation strategies to cope with climate change

  1. Flood defences – e.g., Thames Barrier, raised houses
  2. Drought-resistant crops – help maintain food supply
  3. Water conservation – e.g., rainwater harvesting and irrigation efficiency in arid areas
• How is agriculture adapting to climate change?

  Use of drought-resistant and salt-tolerant crops, changing planting dates, and using more efficient irrigation systems
• How can water supply be adapted to climate change?

  Using rainwater harvesting, building reservoirs, recycling water, and desalination in dry areas
• What are examples of flood adaptation strategies?

  Building sea walls, storm surge barriers (e.g., Thames Barrier), raising buildings, and restoring mangroves for natural flood defence
• How do early warning systems help adaptation?

  They give communities time to evacuate or prepare for extreme weather events like floods or cyclones, reducing loss of life and damage.