4.4 Climate change Flashcards
What are the 2 most significant (largest effect on the Earth) greenhouse gases?
Carbon dioxide and water vapour
What are the 2 most significant greenhouse gases?
Carbon dioxide and water vapour
What does gases do in the atmosphere?
They retain heat
How is carbon dioxide released in the atmosphere and how is it removed from the atmosphere?
- Released by cell respiration in living organisms and also by combustion of biomass and fossil fuels
- Removed by photosynthesis and by dissolving in the oceans
How is water vapour formed and how is it removed?
- Formed by evaporation from the oceans and also transpiration in plants
- Removed from the atmosphere by rainfall and snow
In what form does water continue to retain heat after it condenses?
After it condenses to form droplets of liquid water in clouds
Why does temperature drop so much more quickly at night in areas with clear skies than in areas with cloud cover?
- Water continues to retain heat after it condenses to form droplets of liquid water in clouds
- The water absorbs heat energy and radiates it back to the Earth’s surface and also reflects the heat energy back
What are the 2 greenhouse gases that have less impact than CO2 and water vapour?
Methane and nitrogen oxides
What are the two most significant greenhouse gases?
CO2 and water vapour
How is methane and nitrogen oxides compared to CO2 and water vapour?
CO2 and water vapour - most abundant
Methane and nitrogen oxides - have smaller but nontheless significant effect
What is methane emitted from?
- the 3rd most significant greenhouse gas
- emitted from marshes and other waterlogged habitats and from landfill sites where organic wastes have been dumped
- release during extraction of fossil fuels and from melting ice in polar regions
Where is nitrous oxide released from?
- released naturally by bacteria in some habitats and also by agriculture and vehicle exhausts
Why is oxygen and nitrogen, the two most abundant gases in the Earth’s atmosphere not greenhouse gases?
They do not absorb longer-wave radiation
How much does all the greenhouse gases together make up in the atmosphere?
Less than 1%
What does the impact of a gas depend on?
Its ability to absorb long-wave radiation as well as on its concentration in the atmosphere
Why is methane’s impact on global warming less than CO2?
Because it has a lower concentration than CO2
What does the concentration of a gas depend on?
- Rate at which it is released into the atmosphere
- How long on average it remains in the atmosphere
How quickly does water vapour enter the atmosphere and how long on average does it remain there?
It enters the atmosphere immensely rapid, but it remains there only 9 days on average, whereas methan remains in the atmosphere for 12 years and carbon dioxide even longer
What length wave does the Earth absorb?
The warmed surface of the Earth absorbs short-wave energy from the sun