BIO220 Lecture 22 Flashcards

Greenhouse gasses & climate change

1
Q

Earth entered __th major ice age 2.58 million years ago

A

5

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2
Q

Ice age has alternating ___ and ___ periods

A

glacial & interglacial

- sinusoidal temperature changes

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3
Q

We are exiting the interglacial period in the next…

A

10-50 thousand years

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4
Q

long-term prediction of climate? short-term?

A

long-term: entering glacial period

short-term:

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5
Q

4 pioneers of climate prediction

A
  • Tyndall
  • Arrhenius
  • Bjerknes
  • Richardson
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6
Q

Tyndall’s contribution

A

How different gasses absorb radiation

  • greenhouse effect of water vapour (how water holds heat)
  • diff gasses store diff amounts of heat
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7
Q

Arrhenius’s contribution

A

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
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8
Q

Milankovich cycles

A

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

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9
Q

Why do we have alternating glacial & interglacial periods?

A
  • Arrhenius: CO2 concentration
  • Milankovich: wobbling of earth’s axis
    ^ both contribute
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10
Q

Bjerknes’s contribution

A

Primitive equations for modelling weather

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11
Q

Richardson’s contribution

A

Calculate first numerical weather prediction

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12
Q

ENIAC’s breakthrough prediction in 1950

A

predicted 24h of weather in 24h

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13
Q

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

A

climate

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14
Q

why can’t we predict weather far in advance?

A
  • chaotic nature

- estimation & computation limitations

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15
Q

CLIMATE

A

statistics of weather

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16
Q

How to predict future climate?

A

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

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17
Q

IPCC

A

intergovernmental panel on climate change

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18
Q

Backward prediction (climate)

A

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

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19
Q

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

A
  • model building
  • collect data on past climates
  • validation & approve causes
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20
Q

IPCC was established by __ in __

A

UN;

1988

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21
Q

What does the IPCC do?

A

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

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22
Q

Why was IPCC established?

A

avoid “alarmist” projections by independent scientists

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23
Q

Albedo effect

A

Cools earth; reflection of solar radiation back into space

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24
Q

Greenhouse effect

A

Heats earth; traps infrared radiation emitted by the Earth

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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
31
Major greenhouse gasses ranked by the relative effect per molecule (least -> most). Also list their sources.
1. H2O 2. CO2 (respiration, combustion) 3. CH4 (anaerobic organic decomposition, grazing) 4. N2O (denitrification, combustion) 5. CFC (refrigerants, spray can)
32
Removing which greenhouse gas would have the biggest impact on improving Earth? Why?
CO2; | Even though it does not have as much of an effect as the other greenhouse gasses, there are many more molecules of it
33
Which counties are the biggest emitters of CO2?
- China (overall) | - Canada & Australia (emission/capita)
34
Why are Canada & Australia such big emitters of CO2?
- mining - oil extraction - forestry?
35
Trend: global avg temp
increase
36
trend: global avg sea level
increase
37
trend: northern hemisphere snow cover
decrease
38
Trend: temp changes by region
- overall: increase | - each reach increase slightly differently
39
What is mostly likely the driving factor of temp increase?
CO2
40
Trend: current CO2 levels
exponential increase - before: sinusoidal - higher than ever before
41
Manifestations of current climate change
1. exponential increase of CO2 2. costal areas of Greenland & Antarctica loosing ice 3. sea-level rise 4. loss of Arctic sea ice
42
Rising sea level ___ previous estimate. Data from...
matches; | IPCC & Merrifield (independent group)
43
According to current predictions, we will be ice-free in the Arctic by...
2050
44
Sakura flowering time data shows...
Spring was getting here later and later, but suddenly started getting here earlier
45
Why is the cause of warming not due to increased solar activity? (which data does not match)
- nighttime temp rising faster than daytime ones | - troposphere heating & stratosphere cooling
46
Warming trends that we see
- poles warm faster than mid-latitudes - winter warm faster than summer - nighttime temp rising faster than daytime ones - troposphere heating & stratosphere cooling
47
Why is the cause of warming not just due to solar & volcanic activity?
Models: 1. solar & volcanic activity 2. greenhouse gas activity 3. all of the above Impose model on real data: 3 matches the best
48
Research from Berkley on climate heating results
- graph temperature of earth - put best-fit line - best fit line = activity from CO2 and volcanic eruptions
49
Effect of volcanic eruptions
- release lots of soot - reflect solar radiation back to atm - cools earth dramatically (set global warming back 10 years) - "year summer never came" -> bad for farming
50
Who were the Berkley scientists funded by?
Koch Brothers (skeptics, oil industry) & Gates Foundation
51
post-____rise in temperature is due to ___, says IPCC
1956; | humans
52
most of the globe (2000-2010) warmed up by __C compared to 1900-1910
2
53
80 years from now, Earth's temp will increase about __C
4-6
54
Rising temp effects on human health
- some disease will die because too hot for vectors to survive (malaria) - malnutrition - deaths from extreme weather - cardio-diseases due to bad air quality - reduce cold-related deaths - more diarrheal diseases
55
Weather events will become more extreme because...
atmospheric heat engine will be more powerful
56
limitations of global climate model
- hard to model clouds - coupling of land-ocean atmospheres weak - can't make small-region predictions
57
GCM
global climate model
58
What was the highest temp in the past? When?
Paleocene-Eocene Thermal Max (PETM), 56 MYA - 6C increase in 20 000 years - much higher temp than now - spiked in both temp and CO2
59
PETM was most likely due to...
- some positive feedback mechanism | - melting of frozen methane from ocean (clathrate gun hypothesis)
60
PETM events
- mass extinction of oceanic organisms - oceans acidified from CO2 -> animals can't make carbonate shells - migration of species & biomes - dwarfing of mammals - leaf sizes shrink, increased insect - wet tropical forest -> dry savannah - arctic -> swamps
61
Bergmann's rule
- larger organisms in colder climates | - smaller organisms in hotter climates