Human and natural processes on the carbon cycle. Flashcards
What two natural processes alter the magnitude of the carbon stores?
Wildfires and volcanic eruptions.
What human activity can impact the carbon cycle stores?
Due to rapid industrialisation, humans have exacerbated the process of carbon flows, by extracting huge amounts from the lithosphere and biosphere being transferred to the atmosphere; the main causes for this are, hydrocarbon extraction and use, deforestation, land use change and farming practices.
How do volcanoes change the carbon cycle?
Carbon is stored within the earth in Magma, released in eruptions, entering the atmosphere as co2.
Recent volcanic eruptions have released less co2 than humans; but there is potential for a huge eruption to significantly affect the carbon cycle; Yellowstone.
The Eyjafajallokull eruption in 2010 released 2.8 billion tonnes of carbon into the atmosphere.
How do wildfires change the carbon cycle?
Increase combustion of biomass and soil, which is transferred to the atmosphere. However, the loss of vegetation reduces photosynthesis; less carbon in atmosphere.
In the long term, wildfires increase vegetation through creating space and nutrients for new plants to grow, acting as carbon sinks. Fires can have a neutral affect on the carbon balance.
How does hydrocarbon extraction and use change the carbon cycle?
The mass combustion of fossil fuels flows carbon into the atmosphere. Without humans, the majority of this carbon would remain sequestered.
How does Deforestaion cause changes to the carbon cycle?
Forests may be cleared for commercial use, logging, agriculture or land use, reducing carbon sinks. Also, can cause slash and burn which increases flows to the atmosphere through combustion.
How do farming practices cause change to the carbon cycle?
Agricultural activities release carbon into the atmosphere.
Livestock – Enteric fermentation.
Ploughing can release co2 in soil
Growing rice in paddies releases a lot of methane
Increased world population increased demand for food, increased carbon emissions from farming, also increased mechanisation of farming.
How have land use changes altered the carbon cycle?
Urbanisation has caused not only deforestation, but also the removal of all vegetation. Less carbon sinks.
Concrete production, releases lots of C02, which is used in huge masses for urban growth.
What is the carbon budget? How might different flows in subsystems create balance and how does this determine if something is a carbon source or sink?
The carbon budget is the balance between carbon inputs and outputs - the difference in inputs and outputs to a subsystem.
For example, in the atmosphere, inputs of carbon come from volcanic eruptions, burning fossil fuels, respiration and ocean loss; but this is balanced by the outputs of carbon from the atmosphere into the ocean and photosynthesis, as well as sequestration, decomposition and chemical weathering.
-The balance of inputs and outputs of a subsystem determines if it acts as a carbon source (outputs outweigh inputs) or sink (inputs more than outputs).
