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1

Earth entered __th major ice age 2.58 million years ago

5

2

Ice age has alternating ___ and ___ periods

glacial & interglacial
- sinusoidal temperature changes

3

We are exiting the interglacial period in the next...

10-50 thousand years

4

long-term prediction of climate? short-term?

long-term: entering glacial period
short-term:

5

4 pioneers of climate prediction

- Tyndall
- Arrhenius
- Bjerknes
- Richardson

6

Tyndall's contribution

How different gasses absorb radiation
- greenhouse effect of water vapour (how water holds heat)
- diff gasses store diff amounts of heat

7

Arrhenius's contribution

Overall effect of CO2 as a greenhouse gas
- double CO2 = 4*C increase in global temperature
- alternating glacial & interglacial periods due to fluctuations in CO2 concentration
- coal burning will fend off next ice age

8

Milankovich cycles

interglacial & glacial cycles based on wobbling of earth's axis and our position in the universe

9

Why do we have alternating glacial & interglacial periods?

- Arrhenius: CO2 concentration
- Milankovich: wobbling of earth's axis
^ both contribute

10

Bjerknes's contribution

Primitive equations for modelling weather

11

Richardson's contribution

Calculate first numerical weather prediction

12

ENIAC's breakthrough prediction in 1950

predicted 24h of weather in 24h

13

What can we predict far in advance: weather or climate?

climate

14

why can't we predict weather far in advance?

- chaotic nature
- estimation & computation limitations

15

CLIMATE

statistics of weather

16

How to predict future climate?

Look at mean weather for current month + standard deviations -> project forward.
e.g. April 2014 is 10*C +- 5*C, so April 2020 will probably be about the same

17

IPCC

intergovernmental panel on climate change

18

Backward prediction (climate)

Use method of predicting future climate for data in 1990, and see if predicted result match real result of 2000
- allow us to see if our method of prediction is good

19

Different groups are studying climate around the world. What do they do?

- model building
- collect data on past climates
- validation & approve causes

20

IPCC was established by __ in __

UN;
1988

21

What does the IPCC do?

Review all available research and get a central central opinion -> core findings on climate that everyone can agree
- does not do its own research

22

Why was IPCC established?

avoid "alarmist" projections by independent scientists

23

Albedo effect

Cools earth; reflection of solar radiation back into space

24

Greenhouse effect

Heats earth; traps infrared radiation emitted by the Earth

25

__ of the solar radiation is absorbed by the Earth's surface

1/2

26

___ radiation is emitted from Earth's surface

infrared

27

Past climate cooling is associated with... (Albedo effect)

uplift of mountain ranges -> snowy regions

28

What reflects the most light? What problem does this cause?

Snow > crops > forest > water;
When snow (75%) melts to water (5%) due to heat, Earth with heat even MORE

29

Keeling's annual measurement of CO2 in Hawaii showed...

sinusoidal fluctuations
- drop due to northern summer (photosynthesis)
- rises due to northern winter

30

Keeling's measurement of CO2 in Hawaii showed...

upward trend if you put many years together