Climate change

• Milankovitch's Cycles


  • Earth wobbles on its axis every 23,000 years
  • Earth's tilt changes every 41,000 years
  • Earth's orbit stretches from circular to elliptical every 97,000 years
• Earth is closer to the sun


  Receives more solar energy
• Earth's tilt changes


  Affects the amount of solar energy different parts of the Earth receive
• Earth's orbit stretches from circular to elliptical

  Earth is further away from the sun, resulting in less solar energy
• Sunspots


  Lots of sunspots send out more solar energy, causing a rise in temperatures. Low sunspot activity leads to a Little Ice Age.
• Volcanic eruptions


  Gas/sulphur dioxide and dust absorb/reflect solar energy, e.g. Mt Pinatubo in 1991 cooled the world's climate by 1°C
• Melting ice caps

  Meltwater affects ocean circulation of warm and cold currents. Less solar energy is reflected from ice caps (albedo effect) and more heat is absorbed by the exposed land, raising temperatures.
• Ocean currents change direction and strength

  Can change the climate of the places they flow past, e.g. the warm North Atlantic Drift suddenly stopped 11,000 years ago, triggering a short-term return of the Ice Age.
• Melting permafrost


  Releases carbon dioxide and methane, which are greenhouse gases that trap heat
• Burning of fossil fuels

  Releases carbon dioxide into the atmosphere, increasing the 'enhanced greenhouse effect' and trapping heat
• Deforestation


  Releases carbon dioxide when trees are chopped down/burned. Trees take in carbon dioxide and give out oxygen.
• Cattle ranching

  Cows release methane
• Rice growing in flooded paddy fields

  Produces methane from microbes in decaying organic matter
• Landfill waste decomposition

  Releases methane, which is more powerful at trapping heat than CO2 and remains in the atmosphere for longer
• Peatland decomposition


  Releases carbon dioxide when peat encounters oxygen. Peat is the largest and most efficient land-based store of carbon (carbon sink).
• Car emissions


  Release nitrous oxide, which is 200-300 times more effective than CO2 in trapping heat
• Fertilisers on crops


  React with oxygen in the air to produce nitrous oxide, a greenhouse gas
• Chlorofluorocarbons in old fridges and air conditioning units


  Release CFCs, contributing to the greenhouse effect
• July 2022 was the hottest day ever recorded in Scotland (34.8°C/94.6°F), England (40.3°C/104°F), and Wales (37.1°C)
• The extreme heat caused issues such as heat stroke, dehydration, railway lines buckling, tarmac melting, IT server problems, school closures, and grass fires
• Higher temperatures

  Lead to drought and falling crop yields, causing loss of income for farmers, extra irrigation costs, and increased risk of livestock diseases
• Crop failure

  Leads to malnutrition and famine, forcing people to migrate and increasing reliance on food aid
• Warmer temperatures

  Attract more mosquitoes, increasing the spread of malaria and putting pressure on hospitals
• Forest fires


  Destroy homes and cause more deaths in extreme heat (e.g. 50°C in British Columbia, Canada and Australia)
• Milder winters

  Threaten species such as snow leopards and mountain hares due to lack of snow
• Loss of food and water sources

  Endanger species such as koalas and pandas
• Milder winters


  Reduce snow for the Scottish ski industry, resulting in job and money losses
• Higher winter rainfall

  Increases floods, damaging roads, houses, historical landmarks, and farmland
• Extreme weather events

  Include hurricanes (e.g. Matthew) and blizzards (e.g. the Beast from the East in the UK in 2017)
• Melting ice caps in the Arctic

  Endanger polar bears
• Melting ice caps in Antarctica


  Cause penguin numbers to fall as they spend more time looking for food and less time breeding
• Rising sea temperatures


  Cause coral bleaching, killing 50% of the Great Barrier Reef, and leading to a loss of ocean habitats and warmer waters causing a loss of dolphins
• Sea level rise

  Floods farmland, businesses, power supplies, and housing in low-lying coastal countries like Bangladesh, and causes the loss of coastal golf courses in Scotland
• Sea level rise in the Maldives

  Forces climate change refugees to higher ground
• Reducing greenhouse emissions

  1. Increasing energy production from renewables like wind farms, tidal power, and solar panels

  2. Reducing, reusing, and recycling products to send less waste to landfill sites

  3. Insulating homes, using timer switches, new boilers, and energy-saving light bulbs

  4. Using smart meters to improve energy efficiency

  5. Transitioning to electric buses and cars
• COP26 in Glasgow resulted in the Glasgow Climate Pact, with world leaders agreeing to take action to limit global warming to 1.5 degrees
• The Carbon Credits Scheme allows the polluter to pay according to their pollution, with the money invested in environmental projects to further reduce emissions
• Planting trees and reducing deforestation

  Takes in CO2 and reduces the amount in the atmosphere
• Protecting peatland areas, which are natural carbon stores, is important
• Carbon capture technology, which stores carbon dioxide rather than releasing it into the atmosphere, is in early stages of development and has concerns over long-term security and potential leaks