4. Global Warming and the Greenhouse Effect Flashcards Preview

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Flashcards in 4. Global Warming and the Greenhouse Effect Deck (17):
1

What does the sun emit?

radiation

2

What is radiation?

predominantly short wavelength

3

How much is absorbed by the atmosphere? How much, therefore, reaches the earth?

- 25%
- ozone absorbs much of the ultraviolet
- 75%

4

What happens to solar radiation when it reaches the earth?

it is absorbed and converted to heat

5

What re-emits radiation? At what wavelength is radiation re-emitted?

- the surface of the earth
- much longer wavelength, usually infrared (heat)

6

The earth re-emits radiation. What percentage of this is absorbed by the atmosphere, before passing on out into space? How is it absorbed? What happens next? What is this process called?

- 70-85%
- trapped by gases in the atmosphere
- gases re-emit the radiation, some of it back to the surface of the earth, causing warming
- greenhouse effect; gases that trap the radiation = greenhouse gases

7

Can all gases be greenhouse gases?

no - only certain gases have the ability to trap long-wave radiation

8

What does the impact of a gas depend on?

- its ability to absorb long-wave radiation
- its concentration in the atmosphere

9

What are the most significant greenhouse gases?

carbon dioxide and water vapour

10

What other gases, other than carbon dioxide and water vapour, produce the greenhouse effect?

methane and nitrogen oxides

11

What is the difference between methane and carbon dioxide in their impact on the greenhouse effect?

methane causes more warming per molecule than carbon dioxide (but it is present in lower concentrations)

12

Which level of the ozone does not affect greenhouse gases?

stratospheric ozone is not a significant greenhouse gas - it intercepts more incoming short-wave radiation than outgoing long-wave radiation

13

Name 4 gases that have a significant impact in the greenhouse effect.

1 carbon dioxide
2 methane
3 nitrous oxide
4 halocarbons

*water vapour not included

14

Compare the warming effects of these gases (%)
1 carbon dioxide
2 methane
3 nitrous oxide
4 halocarbons

1 - 63.4%
2 - 18.3%
3 - 6.1%
4 - 12.2%

*water vapour not included because its effects are hard to measure

15

What would the mean temperature of the Earth's surface be without the greenhouse effect? What is the actual mean temperature of the Earth's surface?

-18°C

12°C ; that's 30°C higher

16

What 3 claims linking greenhouse gases, global temperatures, and human activities are indisputable?

- global temperatures and climate patterns are influence by concentrations of greenhouse gases
- human activities cause increases in concentrations of greenhouse gases in atmosphere
- empirical data shows the earth has warmed over the past 200 years

17

What is claim linking greenhouse gases, global temperatures, and human activities is 'strongly' disputed?

whether global warming is due to greenhouse gas emissions from human activity

- most believe human activity to be influencing global temperatures and climate patterns

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