changes in the carbon cycle over time Flashcards
1
Q
what is the Milankovitch cycle?
A
natural change in the shape (circular to elliptical) of the earth’s orbit which influences the amount of sunlight reaching the earth which affects the temperature
2
Q
what happens during colder periods?
A
- restricted plant growth = less co2 absorption
- colder oceans absorb more co2 from atmosphere
- restricted marine biology growth = reduced co2 absorption
- increased sea ice cover = inhibits release of co2 brought to surface by physical mixing, also stops growth of algae which consume co2
3
Q
what happens during warmer periods?
A
- melting of permafrost = release of co2 and methane
- more plant growth
- more photosynthesis
- drier = slow plant growth = slowed uptake of co2
4
Q
how much of earth’s land surface is burned every year?
A
3-4km^2
5
Q
what % of carbon stored in forests is emitted during a fire?
A
10-20%
6
Q
what % of co2 emissions in the US are equivalent to anthropogenic emissions?
A
4-6%
7
Q
between 1997-98 what as the growth rate of co2 in the atmosphere? why?
A
it doubled
Indonesia - fires in deep peat bogs
8
Q
why is the fire and carbon equilibrium getting out of balance?
A
fire suppression, climate warming, increase in fuels and more frequent and severe fires.
