3. The carbon cycle

Question 1

what is carbon sequestration

Answer 1

the long term storage of carbon in plants, soils, geologic formations and the ocean
it occurs both naturally and because of anthropogenic activities
refers to the storage of carbon that has the immediate potential to become carbon dioxide gas

Question 1

what is sedimentation

Answer 1

when shelled marine organisms die their shell fragments fall to the ocean floor and become compacted over time to form limestone
organic matter from vegetation and decaying marine organisms is compacted over time, whether on land or in the sea, to form fossil fuel deposits

Question 2

differentiate inorganic, organic ad gaseous carbon

Answer 2

inorganic - found in rocks as bicarbonates and carbonates
organic - found in a plant material and living organisms
gaseous - found as CO2 and CH4

Question 3

where do we find carbon

Answer 3

Lithosphere - both organic (humic substances and living organic matter) and inorganic carbon (fossil fuels and rocks
carbon in the lithosphere is stable
it forms over long timescales
Hydrosphere - 40000 GtC, organic carbon and dissolved CO2 in the oceans
long carbon cycle when organisms die and sink, forms layers of carbon rich sediments
ocean helps to reduce the amount of CO2 in the atmosphere (dissolving and buffering)
Biosphere - 317 GtC, found in living vegetation, plant litter, soil humus, peat and humus - important in taking in carbon through photosynthesis
soil carbon pool is larger than the atmospheric pool
Atmosphere - carbon dioxide and methane makes up about 0.04% of the atmosphere, at the highest level in the last 2 mil years
attributed to human derived sources like burning fossil fuels and deforestation

Question 4

why do carbon dioxide levels change seasonally

Answer 4

The seasonal cycle of highs and lows (small peaks and valleys) is driven by Northern Hemisphere summer vegetation growth, which reduces atmospheric carbon dioxide, and winter decay, which increases it. The long-term trend of rising carbon dioxide levels is driven by human activities

Question 4

how does tilt affect carbon cycle

Answer 4

Variations in Earth’s orbit alter the amount of energy Earth receives from the Sun and leads to a cycle of ice ages and warm periods like Earth’s current climate. Ice ages developed when Northern Hemisphere summers cooled and ice built up on land, which in turn slowed the carbon cycle.

Question 5

define carbon budget

Answer 5

the amount of CO2 that can be emitted over a period of time that does not lead to an increase in global temperatures

Question 6

why did carbon emissions drop in 2008

Answer 6

the financial crisis meant that there was no disposable income, therefore there was less production of goods as demand decreased

Question 7

define the greenhouse effect

Answer 7

the natural process by which the earth’s infrared radiation is re-reflected and temporarily stored by a layer of greenhouse gasses