Midterm Flashcards
What are the 4 key trends that provide clear evidence that the climate is changing?
Global surface temperature.
Sea level.
Arctic sea ice extent.
Ocean pH.
At steady-state, what balances the net incoming solar radiation at the top of the atmosphere?
Outgoing longwave radiation.
Define the greenhouse effect.
Downward longwave IR to the ground.
List 6 greenhouse gases found in the Earth’s atmosphere and their chemical names.
Water vapour (H2O)
Methane (CH4)
Ozone (O2)
Carbon dioxide (CO2)
Nitrous oxide (N2O)
Halocarbons (CF4)
What are the two main reasons the Earth’s climate response is being delayed?
Heat capacity of oceans.
Latent heat needed to melt ice sheets.
Two main sinks of atmospheric CO2?
Land plants; oceans.
What must happen to CO2 emissions to stabilize the atmosphere CO2 concentration?
Emissions need to be close to zero.
Why does the atmosphere CO2 concentration decrease during Northern Hemisphere summer?
Carbon sink by photosynthesis as plants grow.
Two ways atmospheric aerosols can cool climate?
Scatter radiation to space (direct effect).
Make clouds brighter (indirect effect).
How are we able to determine pre-industrial atmospheric CO2 concentration?
Analyze trapped air bubbles in ice cores.
Two factors that control residence time of a steady-state gas in the atmosphere?
Size/mass of reservoir.
Sink or source rate.
Three main positive feedback mechanisms in climate system?
Water vapour.
Ice albedo.
Clouds (also permafrost).
Where is surface temperature increase expected to be greatest this century?
Arctic.
Most commonly used definition for climate sensitivity?
Temperature increase after a doubling of CO2 from pre-industrial times.
Why does deep ocean water have a temperature close to 0 degrees C?
Source region is ocean surface near Greenland or Antarctica.
Why are subtropical latitudes so dry?
Descending branch of Hadley cell.
Why is the equivalent CO2 concentration always greater than actual CO2 concentration?
Accounts for radiative forcing from all other greenhouse gases.
Why is global warming potential of nitrous oxide much larger than that of methane?
N2O has much longer lifetime.
What type of cloud is best for warming climate?
Cirrus.
What variable is used to define the time varying Representative Concentration Pathway?
Radiative forcing.
Main source of scientific uncertainty in atmospheric climate models?
Cloud feedback.
Main sink and source of CO2 on geological time scales?
Sink: weathering.
Source: volcanism.
What happened during Younger Dryas?
Earth slipped back into ice age.
Why were the monsoons stronger 10,000 years ago?
Earth was closest to sun in July 10,000 years ago, which increased land-ocean temperature difference.
