green house effect & climate chnage

8/10/2019 Green House Effect & Climate Chnage

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The Greenhouse Effect

and the

Enhanced Greenhouse

Effect


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Beforeyou watch

1. Answer these questions:

a) What do fossil fuels contain?

b) What happens when we burn fossil fuels?

c) What does a greenhouse gas do?

d) What happens when more and more greenhouse gases go into the

atmosphere?

e) What happens when the Earth gets warmer?


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Earths energy budget (averaged over the whole

globe and over a long time)

At the top of the atmosphere:Incoming shortwave = Reflected Shortwave + Emitted longwave

At the surface:

Incoming shortwave = Reflected shortwave + Net emitted longwave (emitted - incoming)+ Latent heat flux + sensible heat flux

Sensible

heat 7%

Latent heat

23%

Net Longwave 21%

Yellow:

shortwaveRed:

longwave


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Longwave radiation is

emitted from surface.

Some surface

radiation escapes

to space

Most outgoing

longwave is

absorbed inatmosphere (by

greenhouse

gases)

Greenhouse

gasesemit

longwave

upward and

downward

Some atmospheric

radiation escapes to

space

Some atmospheric

radiation is absorbed at

the surface


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Grain stacks at different

time of the day


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Greenhouse EffectSequence of steps:

1. Solar radiation absorbed by earths surface.

2. Earth gives off infrared radiation.

3. Greenhouse gases absorb some of the Earths infrared radiation.

4. Greenhouse gases (water and CO2) give off infrared radiation inall directions.

5. Earth absorbs downward directed infrared radiation

Result: warmer surface temperature


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How do greenhouse gases affect the environment?

Greenhouse gases, such as carbon dioxide and methane are

accumulating in the earths atmosphere, this causes the

atmosphere to warm up.

The gases allow the suns radiation to enter the earths atmosphere,

but prevent the radiation from escaping the atmosphere. The earth

must be able to release this radiant energy so as not to overheat.

The increase in temperature could produce changes in the worldsclimatic patterns.

The combustion of fossil fuels, such as coal and oil, is a large cause of

carbon dioxide in the atmosphere. These gases have increased as the

result of human activity.

Increases in world temperatures would cause the polar ice caps tomelt causing sea levels to rise. This would result in many coastal

areas to become under water.

Ocean currents could be diverted, if the Gulf Stream were to change,

Europe could become a cooler and drier place. Plant and animal life

could become extinct or be forced to move.


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Economic impacts

Agriculture, forestry, tourism and recreation

could be affected by changing weather

patterns.

Human health impacts are expected to placeadditional economic stress on health and

social support systems.

Damage to infrastructure (e.g., roads and

bridges) from extreme weather events is

expected to increase.

green house effect & climate chnage

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