Transcript 5.2 Greenhouse Effect

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.
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1 of main elements of organic molecs
(carbs, ptns, lipids)
found in 1 of 4 “pools”
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Biosphere
Ocean
Atmosphere
Sediment
Moved b/w them by biolog., geochem.,
industrial processes
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Photosynthesis
◦ Terr./aquatic; CO2 (atmosph/dissolved) removed & fixed
into org cmpds
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Respiration
◦ Metabolize org molecs, release CO2
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Feeding
◦ C through trophic levels
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Fossilization
◦ C trapped in sediment as coal, gas, oil
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Combustion
◦ Burning of fossil fuels/biomass, release CO2
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Greenhouse effect:
◦ NATURAL process
◦ creates moderate temps on earth (life’s adapted)
◦ much less CO2 vs. Venus (200,000x more, sfc
temp = ~20x higher
◦ Without it... avg global temperature would be
-17 C
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a) Short wave solar radiation
(light)
b) light penetrates the
atmosphere and passes
through the molecules of the
atmosphere
c) Absorption by the ground
and conversion to long wave
infrared radiation (heat)
d)This warms the planet
e) Some infrared is lost to
space as heat
f) Atmospheric gases
particularly water vapor,
carbon dioxide, methane and
CFC's
g) Greenhouse gases absorb
infra-red radiation and scatter
this rather than letting it
escape to space. In effect this
traps the heat energy.
h) Some light reflects off the
outer surface of the
atmosphere and never enters
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Human activities may be increasing CO2
levels & other G. gases (methane, N oxides)
May lead to increased global temps and
climate change
Increased greenhouse gases will increase the
particles (f) in the diagram.
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more IR will be absorbed, scattered and retained as
heat
Avg global temps will rise.
◦ Some models: 40C in next 50 years
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predicted to cause global climate changes
“global warming” but while avg global temps rise,
local effects may vary
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Trends:
◦ indicators of potential climate change
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Mauna Loa, HI since 1958
Now worldwide database:
http://cdiac.ornl.gov/trends/co2/siokeel.htm Search “trace gas measurements”
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CO2’s released unevenly around world
Distribution of Vegetation
Lots of assumptions, factors affecting data
analysis
BASIC TREND: increase
Ancient ice core data—longer database,
variety of sources
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Temp
determined by O
isotopes (16:18)
Clear correlation
b/w atm CO2 &
temperature
DOESN’T mean
causation
Levels today
higher than ever
in past
Dashed blue =
extrapolation
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“If the effects of human-induced change
would be large, perhaps catastrophic, those
responsible for the change must prove that it
will not do harm before proceeding.”
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Obligation actually falls on accused causers
of climate change/enhanced greenhouse
effect to show their actions are NOT
damaging
If we wait til it’s proven....too late to reduce
impacts
Better to respond now, even if in long term
it turns out that case can’t be made!
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Skeptic approach:
◦ envtalists need to give conclusive evidence that
‘polluters’ are causing the harm
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PP:
◦ ‘polluters’ need to demonstrate that their actions
DO NOT cause harm—govts, industries,
communities, individuals!!
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Increased freq & intensity of droughts
Flooding
◦ higher rainfalls, more snowmelts, rising sea levels
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Declines in food production
Increased disease—
◦ (generally reduced by cold winters)...
◦ Malaria & Dengue fever CURRENTLY extending their
distribution! 
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More extreme weather
Loss of biodiversity
Sea level simulation
External Links to websites of climate change.
 Weathervane, Environet, Climateark, GCRIO, UCSUSA, NET
External Links to reducing your carbon foot print
 Climatecrisis: calculate your carbon footprint.
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Energy efficient appliances find out about reducing your energy demands in
the house hold.
Simply insulate further information on positive responses to reducing your
carbon foot print.
Cutting energy costs 10 ways to reduce your energy costs.
Energy Audit a self help guide to performing an energy audit on your home.
Standby energy leakage on those appliances that 'leak' power when left to
stand-by.
Alternative energy sources alternative power sources to fossil fuels.
maximize fuel efficiency from your car making the most of the fuel in your
driving.
Hybridcars how hybrids work and a comparison with other methods.
Alternative car fuels Biodiesel, ethanol and more to put in your tank.
Fuel cell vehicles Hydrogen power fuel cells
Vulnerability and Adaptation to Climate Change in Developing Countries
 article by Chris Ward (30th July 2007) for the World Resources Institute,
considers fact that some are working towards own methods of adapting to
climate change rather than how they will reduce climate change:
 'Current scientific evidence shows, however, that some human-induced
climate change is now inevitable and is in fact already occurring. which
regions and groups are most vulnerable to predicted climate flux, how they
might adapt to it
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Bill Heal, The Arctic is an Ecosystem Article
“Predicting changes over the next 50-100 yrs is
difficult!...Most recent model...mean annual temp
of Arctic will rise about 4 C this century...
...coniferous forest will expand –at expense of
tundra
Tundra will be ½-ed by 2100
Will continue to be C-sink b/c increased growth of
forest will exceed increased decomposition