C9

• The Earth's atmosphere has evolved to be composed of about eighty percent nitrogen, 20% oxygen, and other gases like carbon dioxide, water vapor, and noble gases making up less than one percent
• Role of volcanic activity in the early atmosphere


  Produced loads of carbon dioxide, water vapor, and nitrogen along with smaller amounts of methane and ammonia
• Formation of oceans

  Condensation of water vapor into liquid water allowed carbon dioxide from the atmosphere to dissolve in them, forming carbon precipitates and sediments in the seabed
• Reduction of carbon dioxide and increase of oxygen in the atmosphere

  Algae and plants photosynthesize, taking in carbon dioxide and producing oxygen
• The Earth's early atmosphere was mostly carbon dioxide due to intense volcanic activity
• Algae and green plants evolved over the past couple of billion years, leading to a decline in atmospheric carbon dioxide levels and an increase in oxygen levels
• Complex life like animals evolved as oxygen levels increased
• Formation of sedimentary rock, oil, and gas


  Dead algae and plants buried in layers of sediment over millions of years, forming sedimentary rock, oil, and gas which trapped carbon
• Substances formed from buried organisms

  • Crude oil and natural gas from dead plankton
  • Coal from dead plant material
  • Limestone mostly made of calcium carbonate from marine organisms
• Atmosphere today is mostly oxygen and nitrogen due to the decrease in carbon dioxide levels and increase in oxygen levels over time
• Large quantities of sedimentary rock and fossil fuels are found in the ground due to the burial of dead organisms
• first billion years

  lots of volcanic activity

  lots of CO2, H2O, CH4, NOx etc was released

  
• cooling of the earth

  Around a billion years after it formed, the earth began to cool. This allowed water vapour to condense into liquid water and form the oceans.

  When the oceans formed, carbon dioxide dissolved in the water, and carbonates were precipitated, producing sediments.

  this reduced the water vapour and carbon dioxide in the atmosphere
• Atmosphere


  A protective layer of gases around the Earth that acts like an insulating blanket or a greenhouse
• Greenhouse effect

  Gases in the atmosphere absorb and re-emit heat energy, keeping the Earth at a stable temperature
• Greenhouse gases

  • Carbon dioxide
  • Methane
  • Water vapor
• Human activities are increasing the concentrations of greenhouse gases in the atmosphere, leading to global warming
• Reasons for rising carbon dioxide levels

  • Burning fossil fuels
  • Deforestation
• Reasons for rising methane levels

  • Farm animals producing methane during digestion
  • Waste decomposition releasing methane
• Records show a steady increase in Earth's temperature over hundreds of years
• Consequences of global warming are harder to predict due to many variables
• Climate change


  Refers to all effects of global warming on the climate
• Climate

  Long-term weather patterns across the entire planet
• Rare weather events like droughts, hurricanes, and floods


  Become more common and severe due to global warming
• Sea level rise

  Caused by melting ice and expanding warm water in the oceans
• Sea level rise


  May lead to seasonal flooding and submersion of islands and coastal towns
• Climate change impact on wild organisms

  Species may struggle to adapt or migrate fast enough, leading to a potential fall in biodiversity
• greenhouse effect

  • Solar radiation from the sun passes through the atmosphere and hits the earth.
  • Some of this energy is reflected straight back towards space, and some of it is absorbed by the earth and then re-emitted towards space.
  • Some of the energy makes it all the way to space, but much of it is absorbed by small molecules called greenhouse gases.
  • These molecules then re-emit the energy and the whole process of absorption and emission happens over and over again.
  • This trapped energy keeps the atmosphere warmer and more stable than it otherwise would be.
• Global warming refers to the overall increase in the Earth's temperature
• One effect of global warming is the melting of ice caps. This will increase the volume of water in the ocean and could lead to seasonal flooding, or the submersion of entire islands. This is made worse by the fact that water expands when it is heated, so it will also increase in volume.
• weather

  Weather refers to short term atmospheric conditions, like whether it's raining or sunny on a particular day
• Carbon footprints


  Refers to the total amount of carbon dioxide and other greenhouse gases emitted over something's entire life cycle, which could be a product, service, or event
• Benefit of working out carbon footprints

  • Provides a better idea of how environmentally damaging things are, helps in deciding their worth, identifies the most polluting activities to reduce emissions
• Measuring carbon footprints is hard and sometimes impossible due to various factors like sourcing raw materials, manufacturing processes, power usage, disposal methods, and transportation emissions
• A rough calculation of carbon footprints can still give a good idea of the worst emitters and allow for comparison
• Reducing emissions

  Using renewable energy sources like wind, solar, or nuclear energy, implementing more efficient manufacturing processes, reducing waste to prevent methane release, introducing laws or taxes on greenhouse gas emissions, utilizing carbon capture technology to store carbon dioxide underground
• Reducing emissions is challenging due to factors like cost, economy reliance on fossil fuels, government concerns about economic impact, and difficulty in international agreements
• Renewable energy

  Often more expensive than fossil fuels
• Economy reliance on fossil fuels

  Makes it hard to transition to cleaner energy sources
• Government concerns about economy vs. environment

  Make international agreements on emissions reduction difficult