Lecture 10: Greenhouse gases and climate change Flashcards
1
Q
Ice age
A
- Alternating glacial and interglacial periods
- Above line: warmer
- Below line: cooler
2
Q
Four pioneers of climate prediction
A
- John Tyndall
- Svante Arrhenius
- Vilhelm Bjerknes
- Lewis Fry Richardson
- Eunice Newton Foote
3
Q
Tyndall
A
- Measured how different gases absorbed radiation
4
Q
Foote
A
- Discussed greenhouse effect of H2O and CO2
- Suggested that changes in these could lead to climate change
- Published 3 years prior to Tyndall
5
Q
Arrhenius
A
- Calculated overall effects of CO2 as a greenhouse gas
- Doubling of atmospheric CO2 should cause global temperature to increase 4C
- Concluded that alternating glacial and interglacial periods due to this
- Felt that increased coal burning was fending off next ice age
- Contemporaries rejected his CO2 climate connection in favor of Milankovich cycles
6
Q
Bjerknes
A
- Wrote the primitive equations for a model of weather including air movements, temperature, and water content
7
Q
Richardson
A
- Used equations to calculate the first numerical weather prediction
- Predicted weather for 6 hours with calculations taking 6 weeks
8
Q
ENIAC’s breakthrough prediction, 1950
A
- Predicted 24 hours of weather in 24 hours
9
Q
From weather to climate
A
- Can’t predict local weather far in advance because of its chaotic nature
- Climate = statistics of weather, predictable
- How can predictive ability be assessed when future is unknown? Apply backward prediction, compare to past records
10
Q
IPCC
A
- Different groups working in various countries on model building, collecting data on past climates
- Designed to avert alarmist projections by independent scientists
- IPCC does not conduct research; provides protocols and reviews to assess which results are most robust, consistent, and best supported by data, neutral with respect to policy
11
Q
Greenhouse Effect
A
- Some of infrared radiation passes through atmosphere but most absorbed and re-emitted by greenhouse gas molecules and clouds. Effect of this is to warm Earth’s surface and lower atmosphere
12
Q
Charles Keeling measures CO2 at Mauna Loa, Hawaii
A
- Drops taken up by photosynthesis during northern summer
- Recovers during northern winter
- CO2 goes up because of decomposition, etc.
13
Q
Major Greenhouse Gases ranked by total effects and relative effects per molecule
A
- H2O, 0.5
- CO2, 1.0
- CH4 methane, 30
- N2O (denitrification, combustion), 200
- Chlorofluorocarbons (refrigerants, spray can propellants), 30,000
14
Q
Country that is biggest emitter of greenhouse gases
A
- China
15
Q
Countries that are biggest emitter per capita
A
- Canada and Australia
16
Q
Manifestations of climate change
A
- Decreased ice/snow
- Doubling of vegetation
- Quadrupling of wetlands
- Persistent rise in sea levels
- Rapid loss of artic sea ice (12.2% per decade)
