Carbon cycling

A schematic representation of the FeliX model carbon cycle is shown below. Emissions from the energy and LULUCF sectors cycle through the atmosphere into the land sink (biosphere and pedosphere) and ocean.

The formulas for calculating gross flux are shown at left in the diagram below and discussed in the most recent FeliX publication, "Pathways for balancing CO2 emissions and sinks."

The parameterization of the carbon cycle is validated against the Coupled Climate Carbon Cycle Model Intercomparison Project (C4MIP), as shown in the table below.

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Gross Carbon Emissions

FeliX calculates associated gross emissions for each energy source directly from model predictions of primary energy demand and consumption. The plot below illustrates the contribution of each to total annual emissions, listing for convenience the specific values for 2010 and 2100. Overall, gross annual emissions are predicted to rise 66% between 2010 and 2100 in the BAU scenario.

Gross annual emissions in Pg C from land use and land use change; and combustion of coal, oil, gas, and renewable energies (biomass).

Gross annual emissions in Pg C from land use and land use change; and combustion of coal, oil, gas, and renewable energies (biomass).

Historical data from the Carbon Dioxide Information Analysis Center (CDIAC) is shown for land use change, coal, oil, and gas in bold for the period [1900,2005]. This data is used to validate model projections, not for calibration.

The table at right lists emissions intensities for each of the carbon-emitting fuels represented in the model. These are consensus figures, and are not tuned to achieve agreement between IEA energy data and CDIAC emissions figures.

Gross emissions from renewable energies are equivalent to 107% of the carbon stored in harvested biomass (50% carbon by mass plus a penalty per unit weight for agricultural input, harvesting, and transport). Net emissions are significantly reduced due to prior uptake of atmospheric carbon in biomass increments.