Midterm 1 Carbon Cycle

Question 1

Anthropogenic carbon input is relatively small, but imbalancing cycle…. ___ has been taken up by
land/ocean, but other half building up in atmosphere (bathtub model)

Answer 1

half

Question 2

CO2 concentrations will continue rising until emissions drop down to ____

Answer 2

near zero

Question 3

Climate change will further change the carbon cycle

(land plant
growth/fires/permafrost thaw, ocean acidity/temperature/circulation/photosynthesis)

Question 4

Our CO2 will take centuries to millennia to be absorbed into the oceans, and the final 20% or so will take
_______ years to be fully removed from the atmosphere by rock weathering

Answer 4

100,000

Question 5

Long-term geological carbon cycle –

weathering of rocks with slightly ____ rain (H2O+CO2) pulls CO2
sourced from volcanoes out of atmosphere; the rate of weathering depends on the temperature
though, and this sets up a negative feedback loop that provides a long-term thermostat for Earth’s
climate

Answer 5

acidic

Question 6

Rock weathering happens faster when it is ____

Answer 6

warmer

Question 7

Methane is a more potent warmer than CO2, but only stays in the air for ______, so we can quickly
decrease its warming effect if we reduce methane emissions

Answer 7

decades

Question 8

Methane has a big short-term warming effect, but if we decrease emissions, methane levels will quickly drop and reduce warming