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Earth Isn't a Black Body
Many climatologists misunderstand the theoretical physics concept of a black body model. They falsely believe that earth must radiate most of the energy it receives back into space.The black body model is a theoretical concept that can only be approximted in a lab by examining what is called "cavity radiation". It isn't a practical concept for climatology.A planetary black body, if one existed, would absorb all radiation received, become hotter and then convert the heat energy back into radiation.Substances are black if they absorb all radiation. White substances reflect all radiation. Transparent substances allow radiation to pass through. Substances that are transparent or reflective don't radiate well.A black body concept is a simple linear model that only looks at radiation and heat. A linear model can be represented by a relatively simple equation. Non-linear models require complicated equations that may be difficult to solve. Chaotic models may be difficult to represent with equations.For planetary objects the model can only apply to solids in a vacuum and to be fully applicable the solid cannot be reflective. The model cannot apply to planets with a transparent atmosphere because such planets are non-linear. Planets that also have liquid oceans especially a water ocean, are too chaotic to function as black bodies.For a planet with a transparent atmosphere the solid will still heat up after absorbing radiation, but a portion of the heat is transferred to the atmosphere through conduction. The heated air then rises drawing in colder air which is also heated. As the heated air rises the heat energy is converted to potential energy rather than radiation.Water is transparent to light which means it doesn't radiate very well. Water loses heat through conduction and evaporation instead. Conduction heats the air. Evaporation carries heat energy into the atmosphere as latent heat rather than by raising the temperature of the air or by converting heat to radiation.Earth's biosphere further prevents earth from being a black body. From a thermodynamics standpoint, plants are solar energy storage devices. They convert solar energy into the electron bonds that hold complex carbon molecules together. When animals eat plants they store part of the energy as body parts and convert some of the energy into heat part of which may be transferred to the atmosphere through evaporation of water on the skin or exhaling water vapor. Fossil fuels are believed to be plant parts that weren't eaten and continued to store solar energy.A planetary black body is a simple energy in energy out system. Earth's energy utilization system is far too complex for earth to function as a black body. The above discussion is an oversimplification of that energy utilization system.