NetLogo User Community Models
by Systems&Cycles (Submitted: 06/06/2013)
WHAT IS IT?
Carbon Cycle models the fast carbon cycle. The model is intended to examine the effect of human activities on the amount of Carbon in the atmosphere and the upper ocean. Carbon is reported in gigatons. Upper ocean pH is shown.
The model can be initialized to two settings: One represents conditions in 2010; the other represents pre-industrial conditions. The 2010 setting allows for growth of terrestrial biomass. Terrestrial biomass decreases in the 1710 scenario to simulate deforestation for fuel and agriculture.
HOW IT WORKS
Carbon reservoirs and fluxes, especially for the 2010 scenario, are based on the diagram at http://earthobservatory.nasa.gov/Features/CarbonCycle/ (except that I used a terrrestrial plant biomss of 600). The size of the reservoirs are roughly proportionate to the values given in the diagram, although the Deep ocean is somewhat smaller than it should be.
The pools of Carbon monitored are the atmosphere, the upper ocean, and the deposition of calcium-shelled organisms. The sources of Carbon are: emissions, ocean photosynthesis, and land plant (forest) photosynthesis. Land plant photosynthesis and respiration are proprtional to land plant biomas.
The absorption of Carbon by the ocean is affected by the ratio of Carbon in the ocean surface over the ratio of Carbon in the atmsophere. Carbon can go in either direction depending on this ratio. I used 8/10 as a base ratio.
HOW TO USE IT
Use the diagram at http://earthobservatory.nasa.gov/Features/CarbonCycle/ as a reference.
THINGS TO NOTICE
You can make the model crash by adjusting the value of a variable higher or lower. What happens to cause the crash?
THINGS TO TRY
Try to determine what average yearly emissions are necessary to transform the 1710 world to the 2010 world. Also try to develop various scenarios to mitigate the current Carbon problem. Calcification and terrestrial biomass growth can be manipulated for this purpose
EXTENDING THE MODEL
A problem to overcome: under low emissions and high absorption, the ocean becomes depauperate of Carbon. I neede a feedback to return Carbon sequested in biomass and sedimentation.
Watercycle; Global Carbon Cycle; Greenhouse Effect
CREDITS AND REFERENCES
Holian, Gary, Andrei P. Sokolov and Ronald G. PrinnUncertainty in Atmospheric CO2 Predictions from a Parametric Uncertainty Analysis of a Global Ocean Carbon Cycle Model
Keith, H., Mackey, B. G. & Lindenmayer, D. B. 2010 Re-evaluation of forest biomass carbon
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