Greenhouse Gases

• Greenhouse Gases

  . High energy, short wavelength infrared radiation from the Sun passes through the atmosphere and reaches the Earth's surface

  . Some of this radiation is absorbed by the Earth

  . However, lower energy, longer wavelength infrared radiation is reflected by the Earth's surface

  . Greenhouse gases in the Earth's atmosphere absorb this outgoing infrared radiation, which increases the Earth's temperature

  . Without some greenhouse gases, the Earth would be too cold for water to be a liquid and would not be able to support life

  . Greenhouse gases include carbon dioxide, water vapour and methane
• What do human activities increase in the atmosphere?

  Greenhouse gases
• How has the amount of carbon dioxide changed over the last 100 years?

  It has increased
• What correlates with the increase in carbon dioxide levels?

  Increase in fossil fuels being burned
• What do fossil fuels contain that has been locked up for millions of years?

  Carbon
• What happens when fossil fuels are burned?

  They release carbon dioxide into the atmosphere
• How does deforestation affect carbon dioxide levels?

  It increases carbon dioxide levels
• What process do trees perform that helps reduce carbon dioxide?

  Photosynthesis
• What activities increase methane levels in the atmosphere?

  • Decomposition of rubbish in landfills
  • Increase in animal farming
  • Methane produced during animal digestion
  • Decomposition of animal waste materials
• What do many scientists believe about greenhouse gases and Earth's temperature?

  They will increase Earth's surface temperature
• Why is it difficult to produce an accurate model of climate change?

  Many different factors are involved
• What may people use due to the complexity of climate systems?

  Simplified models
• What can result from using simplified models in climate discussions?

  Speculation and partial evidence opinions
• What type of bias might some people have regarding greenhouse gas issues?

  Financial bias from vested interests
• Key Point

  Climate change is a good example of the popular media reporting on scientific ideas in a way that may be oversimplified, inaccurate or biased.

  It is also a good example of an area where scientists can work to tackle problems caused by human impacts on the environment.
• Global Climate Change

  . If the average global temperature increases, this could cause global climate change. The impact of this could include:

  - a rise in sea level, which could cause devastating floods and more coastal erosion

  - more frequent and severe storm events

  - changes in the amount and timing of rainfall, with some areas receiving more rain and other areas receiving much less

  - an increased number of heatwave events, which can be harmful to people and wildfire

  - more droughts

  - changes to the distribution of plants and animals, as some areas become too hot for species to survive and other areas warm up enough to become habitable

  - food shortages in some areas, due to changes in the amount of food that countries can produce
• What is a carbon footprint?

  Total greenhouse gas emissions over life cycle
• What does the carbon footprint of a product include?

  Production, use, and disposal of the item
• How can the carbon footprint be reduced?

  • Use alternative energy supplies (e.g., solar power)
  • Waste less energy
  • Implement carbon capture and storage (CCS)
  • Introduce carbon taxes and licenses
  • Engage in carbon off-setting (e.g., tree planting)
  • Encourage carbon-neutral product choices
• Why is reducing the carbon footprint not straightforward?

  There are multiple complex problems involved
• What are some problems in reducing carbon footprints?

  • Disagreement among scientists on climate change
  • Lack of public information and knowledge
  • Reluctance to change lifestyles
  • High costs of alternative energy production
  • Disagreement between countries on actions
• Key Point

  Climate change is an area where governments and individuals need to make decisions about the best course of action by evaluating evidence and considering all arguments
• Key Point

  Trees use carbon dioxide for photosynthesis and, therefore, reduce the net amount of carbon dioxide reaching the atmosphere. The idea of carbon off-setting is to plant enough trees to balance out the carbon dioxide being produced by manufacturing processes/product use
• Key Point

  Carbon-neutral products lead to no overall increase in the amount of carbon dioxide in the atmosphere