Carbon Cycle Flashcards
how do volcanic eruptions change the carbon cycle
carbon can be naturally cycled from the lithosphere into the atmosphere during a volcanic eruption, with volcanic activity emitting between 130 to 380 million metric tonnes of carbon dioxide per year. during the collision of two tectonic plates, the oceanic plate submerges beneath the continental plate causing the rock it carries to melt under the extreme heat and pressure. subsequently, the heated rock recombines into silicate minerals contributing to the outgassing of carbon dioxide. However, this contributes to only 0.1 petagrams of carbon emitted annually: a significantly smaller carbon transfer than other factors.
how do wildfires change the carbon cycle?
- Natural wildfires occur in ecosystems which experience hot and arid climates due to increased evaporation rates drawing moisture from the soils and leaving leaf litter which is susceptible to ignition.
- For example, wildfires occur frequently along the coastal US state of California where an average of over 8,000 wildfires are experienced annually subsequent to their climatic conditions which have been exacerbated through anthropogenic activities.
- Wildfires transfer carbon from the biosphere into the atmosphere with 11.6 petagrams of CO2 being released during their combustion. wildfires further influence the biogeochemical cycle through leading to a long term reduction of biomass which act as carbon reservoirs through natural sequestration of carbon dioxide during photosynthesis. subsequently, as the biomass combusts it releases the carbon previously stored within it promoting a positive feedback loop as the increased levels of carbon dioxide contribute to the higher temperatures and drier conditions that make environments more susceptible to wildfire risk.
how is urbanisation impacting the carbon cycle?
urban areas occupy 2 percent of the earths land mass yet is accountable for 97 percent of anthropogenic carbon dioxide emissions . as development has proceeded over recent decades due to global population growth there is subsequently greater demand for construction and therefore requires greater production of cement. it is estimated that this production process contributes to 2.4 percent of global carbon emission.
how is agriculture impacting the carbon cycle?
world demand for food is predicted to increased by 60 to 100 percent by 2030 due to growing global populations. alongside this, recent decades have seen an increase in stock densities of livestock due to a higher dependence on meat and dairy products. these animals release high quantities of methane during their digestive processes with up to 60 percent of all agricultural emissions of carbon dioxide attributed to pastoral farming . Methane is also a bi-product of rice cultivation, emitted from microbes in the waterlogged rice paddies.
how does the milankovitch cycle (eccentricity) impact the carbon cycle ?
The Milankovitch cycles cause regular changes of orbital eccentricity, which varies the amount of solar radiation that heats up the earth as a result of the distance changing between the Earth and the sun. During periods of eccentricity when the orbit of the sun is undergoing circular rotation, the earth would experience a hotter and more arid climate due to a 20 to 30 percent greater amount of insolation than during a highly elliptical orbit.
describe carbon capture systems in mitigation of climate change.
CCS uses technology that is able to capture up to 90 percent of carbon emissions generated by fossil fuel powered industrial processes. the technology captures atmospheric carbon before transporting it by pipes to underground sites such as geographical rock formation. AN example of this is the boundary dam in canada which is the first plant to successfully employ ccs. through the construction of CCS, it is projected to cut global carbon dioxide emissions by 10 to 55 percent until 2100. despite this it is viewed with suspicion as it remains unclear the long term effects of the carbon capture and storage as it is an emerging technology.
describe international agreements in mitigation of climate change.
International policies and protocols can be established to ensure global action occurs in response to climate change.The COP 26 summit brought parties together to accelerate action towards achieving the global net zero by the mid century and to keep global temperature increase to below 1.5 degrees in comparison to pre-industrial levels. the agreement successfully gained 140 signatories yet three of the largest greenhouse gas emitters USA, China and India are the more reluctant signatories. In particular, China emits 10 billion tonnes of carbon yet have claimed that they will continue to burn coal up until 2050, meaning they will continue to be accountable for 28 percent of the global C02.
describe using afforestation in mitigation of climate change
biological sequestration involves the net removal of carbon dioxide from the atmosphere to be stored in vegetative biomass and soils. typically terrestrial plants sequester 560 petagram of carbon dioxide through photosynthesis, creating a carbon sink. Encouraging afforestation will expand the size of the carbon sink to promote larger volumes of carbon to be absorbed into the biosphere. The charity Plant Your Future works alongside smallholder farmers to engage in agroforestry in the Amazon situated in Peru. The charity encourages the planting of native timber tree species alongside native fruit tree species which can be harvested for their profit. Subsequently, during the ten years of activity the charity has planted an excess of 80,000 trees.
describe a positive feedback loop between the water and the carbon cycle
- slightly increased surface temperatures are caused due to increased greenhouse gas levels
- this causes increased thawing of artic tundra and permafrost
- this release methyl clathrates and carbon which were previously locked up in frozen organic matter
- this increases the amount of carbon in the atmosphere which has a further heating effect
describe a negative feedback loop between the carbon and water cycles
- slightly increased surface temepratures due to increased carbon dioxide levels in the atmosphere
- increased atmospheric carbon levels causes the growth of plants as carbon is absorbed by photosysnthesis
- this reduces the atmospheric carbon levels which slightly reduces surface temperatures
describe the location of the amazon rainforest
The amazon rainforest is the largest tropical rainforest globally and is situated in the Amazon river basin which is located in south america. The rainforest includes parts of eight south american countries including bolivia and brazil.
impacts of deforestation on the carbon cycle in the amazon rainforest
- Typically, the amazon rainforest is responsible for the absorption of 2.4 billion tonnes of carbon from the atmosphere annually. This demonstrates that the forest acts as long-term net carbon sink. through deforestation, the forest becomes a carbon source, releasing carbon into the atmosphere in the absence of photosynthesis uptaking carbon for synthesis of glucose in plant growth. this is typically an uptake of 21 kg of carbon dioxide by a single tree annually. with the levels of atmospheric carbon rising this can enhance the greenhouse gas effect and contributes to further global warming with reduced reflection of solar radiation from the earth’s surface due to the layer of gases.
mitigation strategies for the amazon rainforest
- selective logging has been implemented which ensures that only a few trees were felled whilst others remain. this enables the forest structure to remain intact and allows the forest to regenerate naturally. this ensures a sustainable way of producing commodities that supply the newly emerging economy in Brazil.
- international agreements were proposed which stated that illegal logging was reduced and timber came from a sustainable source.The forestry Stewardship council allows the use of its logo by companies that operate sustainably to notify consumers they are purchasing sustainable timber
how does the slash and burn technique impact the carbon cycle?
- the process of deforestation is attributed to 20 percent of the total global carbon dioxide emissions however despite it occuring on a global scale deforestation is particularly concentrated within tropical regions. In the developing regions, deforestation occurs through the slash and burn technique due to its cost-effectiveness, which promotes a positive feedback loop to ensue. the combustion of fires contributes to the degradation of soils which converts the soil from a carbon sink to source as the future carbon storage in the soil is decreased.
