4.4 Climate change Flashcards
What are the most significant greenhouse gases?
Carbon dioxide and water vapour are the most significant greenhouse gases.
How is carbon dioxide released into the atmosphere?
Cell respiration and also by combustion of biomass and fossil fuels. It is removed from atmosphere by photosynthesis and dissolving in oceans.
How is water vapour released?
Water vapour is formed by evaporation from the oceans and also transpiration in plants. It is removed from atmosphere by rainfall and snow.
Water continues to retain heat after it condenses and thus absorbs heat energy and radiates it back to the earth’s surface and reflects heat energy back.
What are other greenhouse gases that have less impact?
Other gases including methane and nitrogen oxides have less impact.
How is methane emitted and released?
methane is emitted from marshes and other waterlogged habitats and landfill sites where organic waste have been dumped, and released during extraction of fossil fuel.
How is nitrous oxide released?
It is released naturally by bacteria in some habitats, and agriculture and vehicle exhausts.
How is the impact of greenhouse gases assessed?
The impact depends on its ability to absorb long-wave radiation as well as on its concentration in the atmosphere.
What kind of wave energy does earth absorb and emit?
The surface of earth absorbs short wave energy and re-emits it as longer wave radiation which is reabsorbed by the greenhouse gases if they are too long to retain heat in the atmosphere
What is the relationship between global temperatures and carbon dioxide concentrations?
There is a strong correlation between global temperatures and carbon dioxide concentrations on earth.
Global temperatures and climate patterns are influenced by concentrations of greenhouse gases. (Does not mean it is directly proportional
How is industrialization and climate change related?
There is a correlation between rising atmospheric concentrations of carbon dioxide since the start of the industrial revolution and average global temperatures.
What would be the consequences of global temperature rise on Arctic ecosystem?
CREDIBLE:
- Changes in arctic conditions (reduced permafrost, diminished sea ice cover, loss of tundra to coniferous forests)
- Rising sea levels
- Expansion of temperate species increasing competition with native species (e.g. red fox vs arctic fox)
- Decomposition of detritus previously trapped in ice will significantly increase greenhouse gas levels (potentially exacerbating temperature changes)
- Increased spread of pest species and pathogens (threatening local wildlife)
- Behavioural changes in native species (e.g. hibernation patterns of polar bears, migration of birds and fish, seasonal blooms of oceanic algae)
- Loss of habitat (e.g. early spring rains may wash away seal dens)
- Extinction and resultant loss of biodiversity as food chains are disrupted
Outline one example of how human activity has caused environmental change.
1 mark for human activity 1 mark for name of impact 1 mark for mechanism of impact 1 markfor environmental change
An example might be:
electric power production causing
air pollution through
sulphur dioxide emmision from coal burning power plants leading to acid rain
which can acidify freshwater lakes killing aquatic organisms
Explain why increasing concentrations of dissolved carbon dioxide in the ocean has negative effect on coral reef.
• The increased concentration of carbon dioxide acidifies the ocean / reduce the pH of the ocean;
This acidification makes it difficult / dissolve the skeleton of the coral reef;
• Global warming which causes higher sea temperatures cause major bleaching events to coral reefs. Bleaching occurs when coral respond to stress of warmer water. Some can recover, but many die.
• Coral reefs need to absorb carbonate ions to deposit calcium carbonate / to make their skeleton;
CO2 dissolve in water to form carbonic acid, which becomes hydrogen and hydrogen carbonate ions;
Hydrogen ions reduce the amount of carbonate ions;
