1. The Atmosphere: Earths big blanket
Climate Change
The Atmosphere: Earths big blanket

2. 4.4 Understandings:
Carbon dioxide and water vapour are the most significant greenhouse gases.
Other gases including methane and nitrogen oxides have less impact.
The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere.
The warmed Earth emits longer wavelength radiation (heat).
Longer wave radiation is absorbed by greenhouse gases that retain the heat in the atmosphere.
Global temperatures and climate patterns are influenced by concentrations of greenhouse gases.
There is a correlation between rising atmospheric concentrations of carbon dioxide since the start of the industrial revolution 200 years ago and average global temperatures.
Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter.

3. Topic 4.4 – Climate Change Applications and Skills
Application: Threats to coral reefs from increasing concentrations of dissolved carbon dioxide.
Application: Correlations between global temperatures and carbon dioxide concentrations on Earth.
Application: Evaluating claims that human activities are not causing climate change.

4. Sunlight = short and infrared = long

6. The atmosphere: Earths big blanket?

7. The atmosphere: Earths big blanket
-Vital in regulating temperature: Though temperatures vary between -80◦C to +50 ◦C, mean temp is around 14◦C and remains relatively constant in most places from day to night. In contrast, the moon, which is about the same distance from the sun has temperatures that fluctuate from -150 ◦C to +120 ◦C It is estimated that without the atmosphere earth would be 32◦C colder or -18 ◦C How does the earth regulate itself?

8. Using a “greenhouse” to illustrate the greenhouse effect

9. Sunlight passes through glass
Sunlight is made of short wavelengths, which are not warm
It’s only when sunlight hits objects (plants, soils etc) and its energy is transformed into heat (long wavelength infrared = IR)

10. Now the heat (IR) that has been absorbed by the objects in the greenhouse is radiated out and shared
The hear as IR stays in the greenhouse because the glass is not as transparent to IR heat as it is to sunlight
Reason temperature can be higher than the outside
The glass is acting like an atmosphere

11. CHG’s act in a similar manner to the glass (natural!)
C02 and H20 vapour have the ability to absorb and radiate IR
These act to help maintain the earth surface temperature by radiating the heat back down
NOx and CH4 as well but to less extent

12. Different gas different impact CO2, NOx and CH4?
Different gases have a different impact on the greenhouse effect
Ability of the gas to absorb the longwave radiation IR
Concentration of the gas in the atmosphere

13. Different gas different impact CO2, NOx and CH4?
CH4 has more potential to warm the planet than CO2 but only lasts 12 years versus C02, years.
Since 1750
C02 concentration has increased by 40%
CH4 has increased by greater than 150%
However, atmosphere today:
CH4 concentration is 1700ppb
C02 concentration is 400 ppm
C02 is 200 time greater!

14. Different gas different impact CO2, NOx and CH4?
Same story for NOx
Although N0x has more than 100 times the global warming power than C02 its concentration is only:
320ppb a fifth of CH4
1000 times less that of C02
Concern yes, but not the priority

15. Albedo: ability of a surface to reflect light

16. So how do GHG’s help warm the earth?
Ask if there was no atmosphere (glass) what would happen?
Earth would have no way to retain heat
The GHG’s absorb and re-radiate the IR from low albedo object on earths surface
-Some heat (IR) passes though the atmosphere. Reason it cools at night but when the sun rises it begins to warm again
- also the reason why it feels warmest at 4 when the sun is not at its strongest, the low albedo objects have been absorbing and radiating all day
Winter?

17. And if we alter the blanket?

18. Global climate change is being affected by GHG emissions
Climate refers to the temperature and precipitation patterns over time. Change in these patterns is natural over extended periods of time
Climatologists and paleoclimatologists study climate patters
Use of proxies to understand past climate conditions,
NOS 207

19. Proxy data show 15000 years ago we were in an ice age
10000 years ago it came to an end and we are now in an interglacial period
Last ice age was the result of a 5 degree drop in temperature

20. What causes natural temperature fluctuation?

21. What causes natural temperature fluctuation?
Volcanic activity and particles in the atmosphere
Quantity of radiation from the sun
Position of the continents
Oscillations in ocean currents

22. Positive C02 Feedback loop
As oceans warm up they are less able to absorb C02
Increase in temp  ocean can absorb less  increased C02 in the atmosphere  increased temp  less ability to absorb  increase C02

23. The industrial revolution and GHG’s
Since the 1800’s C02 emissions have been on the rise, increase of 35% in atmosphere
Mainly result of:
fossil fuel based travel
Planes, trains, automobiles
Product manufacturing and transport
Diet high in meat

24. N0x in the atmosphere
Using organic and commercial fertilizers in agrictulure
Burning coal to produce electricity
Cars
Manufacturing products

25. Threats to coral reef How is a reef formed? Very sensitive to pH
temperature
depth

26. Is it us? Are we sure? Are you sure?

28. Arguments:

29. Words to live by: The Precautionary Principle
The precautionary principle denotes a duty to prevent harm or damage, when it is within our power to do so, even when all the evidence is not in.