Fluxes occur naturally in all functioning ecosystems, including forests. ConclusionĪ carbon flux represents the transfer of carbon between carbon stocks, also known as carbon pools. The Net Land-use Change component in the central red section (1.1 PgC yr -1) reflects the stored carbon lost from deforestation and other land use changes. These numbers illustrate the importance of the land sector as a centrally important carbon sink, with forests and trees being a major contributor. Moreover, forest carbon loss can occur in response to climate-induced disturbances– including fire, pests, and invasive species– which could outweigh the greenhouse gas (GHG) mitigation benefits of existing carbon stocks. ![]() As a result, the net (or total) land carbon flux results in an loss atmospheric carbon and increase in vegetative carbon at approximately 2.6 ± 1.2 PgC yr -1. Vegetation also releases 119 PgC yr -1 back into the atmosphere from respiration, decomposition, and other disturbance events like wildfires. Despite significant net carbon fluxes out of the atmosphere and into land and sea stocks, fossil fuels and net land-use change, which together release roughly 9 PgC yr -1, contribute a far greater amount of carbon into the atmosphere, thus negating any previously positive effects.Īs shown in the figure, vegetation absorbs 123 PgC yr -1 and they do this through photosynthesis, where carbon is sequestered and metabolized and stored as sugars. Oceans absorb more carbon out of the atmosphere than they release back into it each year, lending to a net ocean flux of 2.3 ± 0.7 PgC yr -1. The annual carbon exchange flux is represented numerically in PgC yr -1 units, in which 1 PgC is equal to 1 billion metric tons of carbon. Boxes represent carbon stocks, while arrows demonstrate fluxes. The figure presented here shows global carbon stocks and fluxes. In this section, we outline each element of the figure to paint a comprehensive understanding of the mechanisms involved. Global Carbon Movementįigure 1 outlines fluxes of carbon between several stocks, including the atmosphere, vegetation, belowground biomass, fossil fuels, and the ocean. 2 This overview describes the mechanics behind carbon stocks and fluxes and highlight their impact on forest carbon. 1 In simple terms, it is the movement of carbon between land, oceans, atmosphere, and living things. A carbon flux refers to the amount of carbon exchanged between carbon stocks over a specified time. In the first scenario where there is a smaller tube opening, the flux density is bigger, while when the area of the opening is increased, the flux density becomes less because each flux line is further from each other or from the radiating object, while the quantity remains constant.Carbon Stocks, Fluxes and the Land Sectorīy Graham Diedrich, Michigan State University Forest Carbon and Climate ProgramĪ carbon stock, or carbon pool, is a system that has the capacity to store or release carbon. ![]() ![]() The flux density is simply how close flux lines are to each other. In order to maintain the air speed and increase the amount of air flowing through, then the opening must be enlarged. If the wind speed is high and the tube opening (the area) remains constant, the amount of air that flows through is greater. In this case, the simplest way to think of flux is the amount of air moving through a tube. In electromagnetism, force fields and like phenomena, flux is considered as a surface integral and is the energy that flows around or through an electrically charged object. Energy flux – The rate of transfer of energy through a unit area. ![]() Mass flux – The rate of mass flow across a unit area.Momentum flux – The rate of momentum transfer per unit area.Heat flux – The rate of flow of heat in a specific area.For example, the amount of water flowing per square area of a river and the amount of light that hits an area per second are considered types of flux. In transport phenomena such as heat transfer and fluid dynamics, flux is considered the “rate of flow of a property per unit area,” which has the dimension of quantity and time. The word comes from the Latin word “fluxus,” which means flow and was first introduced by Isaac Newton into differential calculus as “fluxion.” Flux is a general term which refers to the flow of a physical quantity through space such as electromagnetic waves.
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