1. What Gases make up the Atmosphere?
Watch:
label the pie-chart shown above
stating the %
say why each gas is important (Digby P. 32)

2. Activities
Now watch
Define - Greenhouse Effect.
Define - Atmosphere
On your diagram of the Greenhouse Effect, quickly add labels from Digby P. 32.
Write a brief explanation of how the Greenhouse Effect works – make sure you explain that it is a natural process – and what the Earth would be like without it e.g. without it Earth would be up to 30˚C cooler – too cold for humans to exist

3. Greenhouse Gases 1 Look at the table below or in Digby P. 32
Which of the Greenhouse Gases is most common?
How is this produced naturally?
Why are plants and trees called a carbon store?
What happens when deforestation takes place?
What other human activities have boosted carbon dioxide levels?
Greenhouse gas
% of greenhouse gas produced
Sources
Warming power compared to carbon dioxide
% increase since 1850
Carbon dioxide
89%
Burning fossil fuels (coal, oil, gas), deforestation which produces carbon dioxide 1
+ 30%
Methane 7%
Gas pipeline leaks, rice in paddy fields, cattle farming.
21 times more powerful
+ 250%
Nitrous oxide 3%
Jet aircraft engines, cars and lorries, fertilisers and sewage farms.
250 times more powerful
+ 16%
Halocarbons 1%
Used in industry, solvents and cooling equipment.
3000 times more powerful
Not natural

4. Greenhouse Gases 2 Year ppm 1800 1820 1840 1860 1880 1900 1920 1940
Looking back at the previous table we can see that there are other greenhouse gases.
Copy out:
Methane emissions result from:
The raising of livestock – recent estimates by scientists suggest that wind given off by cattle makes up 11% of Australia’s carbon footprint.
The production and transport of coal, natural gas and oil
The decomposition of organic wastes (such as uneaten food) in landfill sites
Nitrous oxide emissions result from:
Agricultural and industrial activities
Combustion of solid waste and fossil fuels.
Look at the table below
Draw 3 line graphs to show the rise in the 3 main greenhouse gases (you will need a different scale on the left for carbon dioxide and nitrous oxide than you will on the right for methane) (ppm stands for parts per million).
Year
ppm
1800
1820
1840
1860
1880
1900
1920
1940
1960
1980
2000
CO2
280
282
283
287
291
295
299
310
323
347
386
Methane
700
713
727
756
796
835
871
980
1430
1656
Nitrous oxide
270
271
275
276
286
290
294
304
311
318

5. Facts about the growth of greenhouse gases over time
Copy out and choose correct number:
The world current level of CO2 is the highest reached for
[650,000/ 20 million years].
Even worse it is increasing now at a rate [100/200 ] times faster than at any time in the last [1000/ million years].
Since the 1800s, CO2 concentration has increased beyond its natural amount by about [1/3 or 1/6].
Methane concentration has more than [halved/doubled] since 1800s.
Nitrous oxide concentration has grown less, but has still risen by [16%/60%].

6. The Enhanced Greenhouse Effect
Normally the Greenhouse Effect is like a blanket – you wouldn’t want to take it off because you would be too cold – however putting another blanket on would make you too hot.
The human-produced greenhouse gases are like this extra blanket, resulting in what is called the Enhanced Greenhouse Effect.
… and if more people around the world do not change their lifestyles, the greenhouse effect will be enhanced further, with more ‘blankets’ being added to the atmosphere – a sure recipe for sleepless nights!
Use the information above and Digby P. 34 to help you answer the EXAM STYLE QUESTION:
What is the enhanced greenhouse effect? (3 marks)