lecture 5

Question 1

time lags

Answer 1

takes time to come to equilibrium after a forcing
- warming in the pipeline

Question 2

radiative forcing

Answer 2

how much a forcing will change earth’s energy balance
- calculated before temp of planet adjusts
- instant change between energy in and out

Question 3

climate sensitivity

Answer 3

sensitivity to a change in forcing, taking into account feedbacks

Question 4

Equilibrium climate sensitivity (ECS)

Answer 4

Global mean temp change expected after sufficient time has passed that the atmosphere and upper ocean come into equilibrium after a forcing
- warming expected due to doubling of pre-industrial CO2 levels

Question 5

Transient climate sensitivity (or response) (TCR)

Answer 5

Est amount of warming that will have occurred at the time that double CO2 is reached assuming CO2 increases by 1% a year
- not at equilibrium

by the time we meet double co2 what is our temp

Question 6

Earth system sensitivity

Answer 6

ECS but accounts for slow feedbacks
- higher than ECS bc positive feedbacks must play through to their completion and sensitivity is higher

Question 7

Proxies

Answer 7

Source of climate info from natural and human records that can be used to estimate past climate conditions

stand in for climate in the absence of direct measurement

Question 8

Natural variability of proxies

Answer 8

Different proxies measure differently and have different sensitivities to different aspects of the climate

Question 9

Historical proxy records

Answer 9

○ Agricultural/shipping records
○ Flood gauges
○ Pictures/sketches/paintings
○ Writings
- Personal letters

Question 10

natural proxies

archives

Answer 10

organic, inorganic, isotopes, dating

Question 11

inorganic examples

Answer 11

ice, carbonates, sediments

Question 12

organic natural proxy examples

Answer 12

tree rings, corals, leaf stomata, pollen

Question 13

isotopic proxy examples

Answer 13

stable and radiogenic extracted from
- irradiation
- temperature
- precipitation
- carbon source
- ice volume
- etc

Question 14

dating as a proxy examples

Answer 14

• radiogenic
• annual records (varves, corals, tree rings)
• tephra (time transgressive)
• pollen

Question 15

pollen as a proxy

Answer 15

• readily preserved/resists weathering
• based on very narrow climatic envelopes (indicator species)
• mean temp of warmest month (MTWA)

Question 16

oxygen isotopes

Answer 16

Raleigh fractination in
- marine and ice cores
- foraminifera

Question 17

raleigh fractination

Answer 17

16O evaporates more, 18O condenses and precipitates more
- as clouds move up latitudes, 18O rains out, clouds are now lighter and water for ice sheets is lighter
- so ocean is heavier/denser and ice during glaciation is lighter because less 18O rained into them