1.4 - Climate Change

• The Quarternary period is the most recent geological time period, spanning from 2.6 million years ago to today
• In the period before the quarternary period, the Earth's climate was warmer and quite stable.
• Evidence of climate change:

  • Ice cores - Scientists analyse gases trapped in a long core of ice to determine the temperature changes overtime
  • Temperature Records - Using things like thermometers and historical weather reports and harvest dates can further date the change in climate
  • Pollen Analysis - Scientists identify and date preserved pollen to show which plant species were living at that time
  • Tree Rings - Scientists take cores and count rings to find the age of a tree, the ring thickness shows what the climate was like
• Natural Causes of Climate Change:

  • Orbital Changes - Variations in way earth orbits the sun (stretch, tilt, wobble) affect how much solar radiation we receive, and may have been the reason behind glacial periods
  • Volcanic Activity - Major eruptions eject large quantities of material into the atmosphere, some of these reflect the sun's rays causing the earth to cool causing short-term changes in climate
  • Solar Output - Changes in the sun's energy output may lead to some minor effects towards climate change, reduced solar output can cause the climate to be cooler in some areas
• Human Causes of Climate Change:

  • Burning fossil fuels - CO2 released into the atmosphere when fossil fuels are burnt
  • Cement Production - Since it is made of limestone which contains carbon, when it is produced it emits a lot of CO2
  • Farming - Livestock produces a lot of methane, and flooded rice paddies can emit methane
  • Deforestation - Plants which take in CO2 are destroyed which stops CO2 from being absorbed, as well as CO2 being released from burning wood
• Effects of Climate Change on the Natural World:

  • Glacial shrinkage due to rising temperatures
  • Sea Ice Shrinkage due to rising temperatures
  • Rising Sea Levels due to melting sea ice
  • Species decline (e.g. Coral)
  • Changing precipitation patterns
• Effects of Climate Change on the Human World:

  • Deaths due to heat have increased
  • Water shortages in many places
  • Many crops worldwide suffering due to rising temperatures
  • Lower Crop Yields worldwide
  • Increasingly extreme weather
• Mitigation Strategies to reduce Climate Change:

  • Alternative Energy Production - Using nuclear and renewable energy to reduce greenhouse gas emissions (e.g. UK using more offshore wind farms)
  • Carbon Capture - Capturing CO2 and transporting it to safe places where it can be stored (e.g. underground)
  • Planting Trees - Increases amount of CO2 which is absorbed from the atmosphere through photosynthesis
  • International Agreements - The 2015 Paris Agreement aims to reduce greenhouse gas emissions and to limit global warming.
• Adaptation Strategies for Climate Change:

  • Changing Agricultural Systems - Planting new crop types more suited to conditions, or using biotechnology to make more resistant crops
  • Managing Water Supply - Water meters, rainwater/waste water can be collected and recycled
  • Coping with Rising Sea Levels - Better flood warning systems, physical defences, building raised flood shelters