W&C - Carbon Cycle Flashcards
what are the transfers in the carbon cycle? (explain them)
- photosynthesis - plants take in carbon dioxide and water, and release oxygen and glucose (reduces stores in the atmosphere, increases stores in the biosphere)
- respiration - animals and plants respire, which releases carbon dioxide into the atmosphere
- decomposition - decomposers break down dead organisms, which releases carbon dioxide into the atmosphere or into the soil
- combustion - burning of fossil fuels release carbon dioxide into the atmosphere
- weathering and erosion - carbonation (when air mixes with rainwater to create an acid that erodes rocks) increases carbon dioxide in the atmosphere when that acid evaporates, after entering the oceans
- burial and compaction - dead organisms fall to the ocean floor and become compacted over time - form fossil fuel deposits
- carbon sequestration - capturing carbon from the atmosphere and storing it in the ground
give 2 advantages of carbon sequestration
- potential to capture 1/2 of the world co2 emissions
- can easily be added to existing coal power stations
gives 2 issues with carbon sequestration
- high costs
- increases the energy demand of power stations
what is a sere?
the carbon cycle occurring on a local scale
what are the main global stores of carbon (in order of magnitude)?
- marine sediments and sedimentary rocks
- oceans
- fossil fuel deposits
- soil organic matter
- atmosphere
- terrestrial plants
what are the physical factors affecting the carbon cycle over time? (explain them)
- wildfires - transfers co2 from the biosphere to the atmosphere (impacted by climate change or human induced ones)
- volcanic eruptions - released stored carbon, also create gases that can block solar radiation and lower global temperatures
what are the human factors affecting the carbon cycle over time? (explain them)
- fossil fuel use - transfers co2 from long term stores into the atmosphere
- deforestation - releases carbon stores in the biosphere into the atmosphere
- farming practices - cow manure releases methane, which contains carbon
what is a carbon source?
a store that emits more carbon than it absorbs
what is a carbon sink?
a store that absorbs more carbon than it emits
explain the process of the enhanced greenhouse effect
- increased burning of fossil fuels means there is an abundance of greenhouse gases in the atmosphere
- these trap even more solar radiation and prevent it from being reflected
- causes global warming and is leading to climate change
what are the causes of the enhanced greenhouse effect? (explain them)
- deforestation - releases large amounts of CO2 from the biosphere into the atmosphere
- land use change -farming practices such as cattle farming releases methane into the atmosphere, which contributes to global warming
- urbanisation - occupy 2% of the lands mass, but account for 97% of co2 emissions
explain the Milankovitch cycle
- changes in the earths orbit
- impacts how much sunlight it receives
- results in accumulation or ablation
how does the Milankovitch cycle impact changes in stores of carbon?
- melting glaciers or ice sheets release stored carbon
give an example of a positive feedback loop
- rising temperatures melt ice sheets
- sea has a high albedo (absorbs more sunlight)
- increase in sea levels means even more sunlight is absorbs
- leads to a further rise in temperatures
- melts even more ice sheets
give an example of negative feedback
- warmer temperatures allow plants to grow in new areas
- increase in vegetation absorbs more co2 from the atmosphere
- reduces the warming effect
