Radiated Energy and the Second Law of Thermodynamics
13 Pages Posted: 12 Dec 2016
Date Written: March 12, 2012
The transfer of thermal energy by radiation is discussed in the context of the Earth's surface and its atmosphere. When considering what happens as the Sun is warming the surface each morning, it is noted that its radiation is being directed onto the land surfaces and some distance below the surface of the oceans. So, additional radiation supposedly transferring further thermal energy from the cooler atmosphere to the warmer surface would violate the Second Law of Thermodynamics. This law must apply (on a macro scale) between any two points at any particular time. An apparent violation cannot be excused on the basis of "net" radiation, because "net" radiation has no corresponding physical entity and is meaningless and useless for determining heat flow in situations when other processes are also involved.
It may be deduced that none of the radiation from a cooler body (and only a portion of the radiation from a warmer body) has any thermodynamic effect on the other body. All such radiation from a cooler source is rejected in some way, and it can be deduced that resonance and scattering occurs without any conversion to thermal energy. The radiation continues in another direction until it strikes a cooler target, which could be in space.
Furthermore, the stability of sub-surface temperatures will tend to maintain the observed close thermal equilibrium at the interface between the surface and the atmosphere. Hence other heat loss mechanisms are likely to adjust, in order to compensate for any reduced radiation.
Some commonly raised questions are answered in the Appendix, where there is also discussion of temperature trends and climate cycles, as well as counter arguments for several possible objections to matters raised herein.
Keywords: Climate Change, Global Warming, Carbon Dioxide, Greenhouse Effect, Radiative Heat Transfer, Back Radiation, Planck Function, Second Law of Thermodynamics, Stefan-Boltzmann Law, Wien's Displacement Law, Greenhouse Gas, Climate Cycles
JEL Classification: Q54
Suggested Citation: Suggested Citation