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SCIPAD - BIG IDEAS - BOOK 2
FUELS AND CLIMATE CHANGE
The Greenhouse Effect
Earth’s atmosphere acts like a blanket around the Earth. In 1896 the chemist Svante Arrhenius
suggested that carbon dioxide acts like the glass in a greenhouse, trapping heat in the atmosphere.
If the Earth had no atmosphere, the average surface temperature would be -18 °C, much colder
than our actual average temperature of 15 °C. At night the situation would be much worse. The
surface would cool down to around -160 °C soon after the sun went down because the surface
would lose heat to space very quickly.
The atmosphere’s ability to keep the Earth warm is called the ‘Greenhouse Effect’. About 80-90%
of the Earth’s natural greenhouse effect is due to water vapour, a strong greenhouse gas. The
remainder is due to carbon dioxide, methane, and a few other minor gases.
A T M O S P H E R E
G R E E N H O U S E G A S E S
G R E E N H O U S E G A S E S
G R E E N H O U S E G A S E S
G R E E N H O U S E G A S E S
Solar radiation passes through the
atmosphere.
Some solar radiation is reflected by the
atmosphere and the Earth’s surface.
Solar radiation is absorbed by the
surface, warming it. The warm surface
radiates heat as infrared radiation.
Greenhouse gases reflect some of the
infrared radiation back to the Earth,
making the Earth warmer.
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1. Name the scientist who first proposed that carbon dioxide played a role in keeping the Earth
warm.
2. (a) State the current average surface temperature of the Earth.
(b) State the average surface temperature of the Earth if it had no atmosphere:
(i) During the day. 			 (ii) During the night.
3. Do greenhouse gases trap (a) Solar radiation?
				 (b) Infrared radiation?
4. Name the three major greenhouse gases.
5. The planet Venus’s atmosphere is 96.5% carbon dioxide, compared to 0.039% carbon
dioxide in Earth’s atmosphere.
(a) Would you expect Venus to have a higher or lower average surface temperature
than Earth?
(b) Explain your answer to (a). 


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