Carbon dioxide and methane as greenhouse gases

• What do greenhouse gases maintain on Earth?

  Temperatures high enough to support life
• Which gases are considered greenhouse gases?

  Water vapour, CO₂, and CH₄
• What is the greenhouse gas effect?

  • Electromagnetic radiation from the sun passes through the Earth's atmosphere
  • The Earth absorbs some radiation and warms up
  • Some heat is radiated as infrared radiation
  • Greenhouse gases absorb some of this infrared radiation
  • The atmosphere warms up, leading to the greenhouse effect and global warming
• What human activities contribute to an increase in greenhouse gases?

  Driving, consuming electricity, raising livestock, and decay of organic waste
• How do human activities increase levels of CO₂ and CH₄?

  Through activities like driving and raising livestock
• What do many scientists believe about human activities and Earth's temperature?

  They believe human activities will cause an increase in Earth's atmospheric temperature
• Why is it difficult to model global climate change?

  Because it involves complex systems
• What can result from simplified models of climate change presented in the media?

  They may be based on only parts of the evidence and may be biased
• What is a major cause of climate change?

  An increase in average global temperature
• What are the potential effects of global climate change?

  • Extinction of species
  • Raising sea levels due to melting polar ice caps
  • Migration of people from drought/flooding areas
  • Decrease in crop yield for all major world crops
• What is the carbon footprint?

  The total amount of CO₂ and other greenhouse gases emitted over the life cycle of a product
• How can the carbon footprint be reduced?

  By reducing emissions of carbon dioxide and methane
• What are some methods to reduce carbon emissions?

  Using less electricity, reducing travel, and planting more trees
• What challenges exist in reducing carbon emissions?

  It can be more difficult, expensive, and land for crops may be lost