The greenhouse effect
Topic 5.2
Assessment Statements
5.2.1 Draw and label a diagram of the carbon cycle to show
the processes involved.
5.2.2 Analyse the changes in concentration of atmospheric
carbon dioxide using historical records.
5.2.3 Explain the relationship between rises in concentrations
of atmospheric carbon dioxide, methane and oxides of
nitrogen and the enhanced greenhouse effect.
5.2.4 Outline the precautionary principle.
5.2.5 Evaluate the precautionary principle as a justification
for strong action in response to the threats posed by the
enhanced greenhouse effect.
5.2.6 Outline the consequences of a global temperature rise
on arctic ecosystems.
Draw and label a diagram of the
carbon cycle to show the
processes involved.
Analyze the changes in concentration
of atmospheric carbon dioxide using
historical records.
Explain the relationship between rises in
concentrations of atmospheric carbon dioxide,
methane and oxides of nitrogen and the
enhanced greenhouse effect.
 How the greenhouse effect works
1. Sunlight enters Earth’s atmosphere b/c the
gases of the atmosphere are transparent to
light
2. Most is reflected off surface
3. Some is transferred into heat energy and
warms the planet which in turn radiates much
back to the atmosphere
4. Greenhouse gases trap heat in atmosphere
 Earth is undergoing
global warming b/c
human-generated
greenhouse gases are
causing the
atmosphere to retain
more and more heat
 Carbon, methane, and
oxides of nitrogen are
main culprits
 Oxides of nitrogen:
– Burning fossil fuels
– Organic and
commercial fertilizers
– Industrial processes
 Methane:
– Cattle ranching
– Waste disposal in
landfills
– Production and
distribution of natural
gas
Outline the precautionary
principle.
 An ethical theory which says that action
should be take to prevent harm even if there
is not sufficient data to prove that the
activity will have severe negative
consequences
Evaluate the precautionary principle as a
justification for strong action in response
to the threats posed by the enhanced
greenhouse effect.
 Preventative action should be taken now to reduce
carbon emissions and greenhouse gases before it’s
too late
 Those who wish to continue producing excess
greenhouse gases should prove that there are no
harmful effects before continuing
 Concerned scientists say that money spend now on
preventative measures is not money wasted
 Prevention is better than cure
Outline the consequences of a global
temperature rise on arctic
ecosystems.
 More and more ice is melting every year
 Less snow and more frozen rain in the winter
 Some regions which never had them before are
now populated with mosquitoes
 Certain woody shrubs are proliferating on warmer
soils where once there were only mosses and
lichens on tundra
 Bird species such as robins have moved into areas
where they are so foreign to the local people that a
name for them does not exist in their language
 Ecosystems are changing
 Intact ice has capacity to harbor algae on its
underside; less ice, less algae, less
photosynthesis, less food
 Less ice, more open water for seals to come
up for air and thus polar bears make fewer
kills
 Detritus frozen in tundra will thaw and
begin to decompose, releasing more carbon
dioxide and methane