The Carbon cycle: changes over time Flashcards
(22 cards)
Natural processes
How do wildfires and volcanic activity contribute to the carbon cycle?
Wildfires transfer carbon from the biosphere to the atmosphere as CO2 is released through burning = encourages growth of plants in the long term.
Volcanic activity; carbon stored within earth is released during volcanic eruptions. Volcanic winters = reduce photosynthesis which can affect tThe water cycle.
Human impacts
How does fossil fuel use contribute to the carbon cycle?
Combustion transfers CO2 to the atmosphere from a long-term carbon sink.
Human impacts
How does deforistation contribute to the carbon cycle?
Often used to clear land for farming/housing, rapidly releases carbon stored in plants using slash and burn techniques and interrupting the forest carbon cycle.
Human impacts
How do farming practices contribute to the carbon cycle?
Pastoral farming releases CO2 as animals respire, affecting the carbon cycle.
Ploughing can release CO2 stored in the soil as well as farming machinery (tractors).
Human impacts
How do changes to the magnitude of carbon stores contribute to the carbon cycle?
Overtime they are called fluxes and may happen quickly or over thousands of years. Human activity causes an unprecedented flux in the levels of CO2 in the atmosphere as a direct result of fossil fuel combustion.
What is the carbon budget?
The balance between carbon inputs and outputs to a store at any scale or the balance exchanges between the 4 major stores of carbon.
What is the enhanced grrenhouse effect?
Green houses gases which are produced by humans trapped radiation from the sun = global warming and leading to climate change.
What is radiactive forcing?
The difference between incoming solar radiation absorbed by the Earth and the energy radiated back out into space. This has increased in recent years, leading to more heat being trapped. Increased global temps due to alteration of the carbon cycle will have significant impacts on the water cycle = greater levels of evapotranspiration.
Causes of the greenhouse effect
Land use change: farming practices in the Amazon, approx 70% of deforestation is for cattle ranching- produces loads of methane = contributing to global warming.
Fertilisers: source of greenhouse gases.
Deforestation: accounts for approx 20% of all global greenhouse emissions.
Urbanisation: replacing countryside with buildings and other similiar infastructure- affects local and global carbon cycles.
What is the impact of the carbon cycle on tropical rainforests?
Regional climates
High rates of photosynthesis & repiration = humidity, clound cover and precipitation.
What is the impact of the carbon cycle on oceans?
Regional climates
Warmer oceans store less CO2 = higher temps = lessen effects of ocean being a carbon sink = positive feedback look, hightens the greenhouse effect.
What is a negative feedback loop?
The process that occurs is counteracted by an opposing process, causing effect to cancel eachother out and nothing to change.
What is a positive feedback loop?
A process occurs which causes another process to occur, starts a chain reaction that heightens the first process.
Examples of postive feedback:
Wildfires, produce loads of CO2
Ice reflects radiation from the sun- as sea temps rise = ice melts= less ice to reflect radiation
Thawing of permafrost due to higher temps
Melting of permafrost.
Land drainage
What is a Moorland?
Also known as peatland
Expanse of waterlogged, acidic soil and peat
Whats the impact of moorland?
Waterlogged ground stops oxygen from permeating = reduces plant growth.
Major store of CO2.
How do Moorlands impact the carbon cycle?
Moor/peatland drained
Water table is lowered = affects flows of water cycle
Dry peat degrades easily
As the water table lowers, air is able to aid decomposition of the peat, releasing carbon dioxide.
Tropical rainforests: interrelationships between the cycles
Natural rainforest water cycle: precipitation falls.
75% intercpeted by trees
35% reaches ground and infiltrates soil, 35% used by plants
25% evaporates
Tropical rainforests: interrelationships between the cycles
Deforested rainforest water cycle:
Precipation falls
Most reaches ground immediately with little veg to intercept rainfall = high surface runoff = flood risk
Less evapotranspiration = less humid = rainfall decreases
Tropical rainforests: interrelationships between the cycles
Natural rainforest carbon cycle:
Trees suited to humid and warm conditiions = promptes photosynthesis
Trees absorb oxgyen = carbon sink
Decompostion and respiration releases CO2 back into atmoshpere and soil, carbon stored
Tropical rainforests: interrelationships between the cycles
Deforested rainforest carbon cycle:
Lack of trees so photosynethsis is reduced
Fires to clear land = CO2 released; forests become a crbon source instead of sink
Lack of life until new plants grow
Low rates of decomposition
