Houghton Ch 3 (The greenhouse gases)

Question 1

What are the greenhouse gases?

Answer 1

Gases in the atmosphere which, by absorbing thermal radiation emitted by the Earth’s surface, have a blanketing effect upon it.

Question 2

What are the important greenhouse gases that are directly influenced by human activities?

Answer 2

Carbon dioxide, methane, nitrous oxide, CFCs and ozone.

Question 3

What characteristics determine a greenhouse gases ‘importance’?

Answer 3

There concentration in the atmosphere and on the strength of their absorption of infrared radiation.

Question 4

Where does the majority of fossil fuel burning occur?

Answer 4

About 95% of fossil fuel burning occurs in the northern hemisphere, so there is more carbon dioxide there than in the southern hemisphere.

Question 5

What does the fact that CFCs are so chemically unreactive mean?

Answer 5

Once they are released into the atmosphere they remain for a long time before being destroyed.

Question 6

What serious environmental problems can CFCs cause?

Answer 6

They destroy ozone- The Ozone layer protects all life on Earth from the harmful effects of the Sun’s rays.

Question 7

Why do small particles suspended in the atmosphere (known as aerosols) affect the energy balance?

Answer 7

Because they both absorb radiation from the Sun and scatter it back to space.

Question 8

What are some sources of atmospheric particles?

Answer 8

Natural causes:

• blown of land surface
• forest fires
• volcano ejecta

Human causes:
- chemical action on sulphur dioxide (power stations etc)

Question 9

Define radiative forcing

Answer 9

The radiative imbalance at the top of the troposphere rather than at the top of the whole atmosphere.