Reservoirs, pools, and stocks
Definition (Encyclopedia of Global Warming)
Reservoirs, pools, and stocks are designations used in box models. A box model is a simplified version of a complex system, in which various parts of that system are reduced to boxes that are linked by fluxes. A reservoir is any box within that system that can accumulate, store, or release the substance of interest. In box models of the global carbon system, the oceans, terrestrial plants, soil, and rocks are examples of reservoirs. The atmosphere is typically not considered to be a reservoir. “Pool” is a term that is synonymous with “reservoir” but can include the atmosphere.
Stocks are the actual accumulations of the substance of interest. Thus, in a box model of the global carbon cycle, the stock is the mass or amount of carbon in various forms—including carbon dioxide (CO2) gas and dissolved species or solids, such as organic matter or inorganic minerals—in each reservoir. The stock in each reservoir is assumed to be well mixed, so that regardless of the size of the reservoir, the concentration of stock throughout the reservoir is uniform. The stock present in each reservoir can change over time, as the rate of input or output from each reservoir varies. In simple box models, reservoirs or pools are held to constant volumes. In more complicated models, the size of a reservoir can change. Numerical methods and computer programs are utilized with box models to solve equations to determine parameters such as the...
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Significance for Climate Change (Encyclopedia of Global Warming)
Box models, as simplified conceptual models of complex systems and processes, are of fundamental importance for predicting future climate conditions. Results from such models underlie the predictions that are published by the Intergovernmental Panel on Climate Change and other scientific and policy-making bodies. Such models can be applied to any complex system, regardless of scale, such as the global carbon cycle or the biochemical processes in a single cell. With regard to future global warming scenarios, variations in the global carbon cycle are among the fundamental drivers of climate change. Other topics of interest include the global cycles of water, nitrogen, oxygen, and sulfur.
In the development of a box model, the reservoirs and stocks of the species of interest are fundamental properties that must be defined in order to perform the necessary calculations. One of the largest sources of error in box models involves defining the size of reservoirs and pools and determining the amount of stock in each. For example, within the global carbon cycle, the stock of carbon present as gas hydrates in the seafloor is presently not well known. This value must be estimated from a relatively low number of measurements in specific regions and extrapolated to all other places on Earth where these compounds might be present. Gas hydrates have been a source of discussion in the scientific community as a trigger for...
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Further Reading (Encyclopedia of Global Warming)
Berner, Robert A. The Phanerozoic Carbon Cycle: CO2 and O2. New York: Oxford University Press, 2004. Berner is a pioneer in the field of biogeochemistry and is one of the creators of the BLAG numerical model, which was used to simulate the carbon cycle over geological timescales. In this book, he discusses that model, assuming a minimal background in mathematics and geochemistry. Illustrations, figures, tables, references, index.
Denman, Kenneth L., et al. “Couplings Between Changes in the Climate System and Biogeochemistry.” In Climate Change, 2007—The Physical Science Basis: Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by Susan Solomon et al. New York: Cambridge University Press, 2007. Provides an overview of the global carbon cycle and how variations in this cycle are used in climate change models. Illustrations, figures, tables, maps, references.
Kennett, James P., ed. Methane Hydrates in Quaternary Climate Change: The Clathrate Gun Hypothesis. Washington, D.C.: American Geophysical Union, 2003. Presents Kennett’s clathrate gun hypothesis, whereby rapid climate change is driven by the release of large amounts of methane from gas hydrates in a geological instant. Gas hydrates are one example of a reservoir in the global carbon cycle. Illustrations, figures, tables, references.
Roston, Eric. The...
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