Ned and Karl often run into people on twitter who tell them that their ‘theory’ violates the 1st Law of thermodynamics. Firstly, as Ned points out, their empirical work is not a theory, but a discovery. But let’s allow Paul to develop his argument, and then we’ll pick it apart and see if it ‘holds water’.

Paul Alter@PAlterBoy1 writes: I wrote this up with the help of a physicist and a climate scientist. You have a gas in a cylinder with a piston. Kinetic energy is applied to the piston. The piston adds energy to the gas through its work: the work by a force is the force times the distance the force (work).

2/ point is moved into the direction of the force. The piston exerts a force on the gas and when it moves to compress the gas it “works” and hence adds energy. The energy that the moving piston adds to the gas is converted into heat, to the effect that total energy is conserved.

3/ This heats the gas. The ideal gas law (PV=nRT) together with conservation of energy determines how much goes into temperature and how much in pressure. So far so good. But now the gas is compressed. What keeps the temperature elevated? It is *not* because the gas is compressed

4/ The energy to compress the gas and raise the temp came from *outside* the system as kinetic energy. Therefore the system will now come to equilibrium; the warmed gas will cool/come to equilibrium with its surroundings. To keep the temp raised there must be continually applied

5/ energy from outside the system. That’s required by thermodynamics. The only possibility in Nikolov’s hypothesis is gravity. But for that to work the gas *must* continue to be compressed even more. If gravity holds it at the same pressure then the system is at equilibrium and

6/ must eventually go to a lesser energy state as energy is lost, as is required by thermodynamics, and cool. So for our atmosphere to stay warm, or get warmer, it must be compressed more and more. And that simply isn’t happening. Ned’s hypothesis doesn’t hold water.

OK, what we’ve got here is a common misunderstanding of Ned and Karl’s work, with a couple of errors in its formulation. Let’s start with the obvious errors and then move onto broader issues with this type of argument.

Firstly, the statement at 4/ that “The energy to compress the gas and raise the temp came from *outside* the system as kinetic energy” is true for the piston experiment but not for the planetary atmosphere, where it is the FORCE (not ‘energy’) of gravity, acting on atmospheric mass, that performs the compression.

Secondly, the statement that “the warmed gas will cool/come to equilibrium with its surroundings” is misconceived. The entire atmosphere wrapped around the whole planet is ‘the warmed gas’, so which ‘surroundings’ does Paul think it is going to cool to or equilibriate with? Not space, because that is “outside the system” so far as his thought experiment is concerned. Not the ground, because energy is actually escaping from the ground into the ‘the warmed gas’.

Paul states in 5-6/ that “If gravity holds it at the same pressure then the system is at equilibrium and must eventually go to a lesser energy state as energy is lost, as is required by thermodynamics, and cool.” but this runs into the same difficulty.

The problem with this type of argument is that the entire thought experiment is set up in the wrong way as an initial compression and subsequent equilibriation in a closed system which looks nothing like the situation the argument is applied to. Most of these type of thought experiments take place in a perfectly insulated vessel which wouldn’t cool. But in any case, it’s not a static system where we have compressed gas in a container. We should consider the real dynamics.

The Sun’s shortwave radiant energy is entering the system and long wave radiant energy is leaving it continuously. What we should be interested in is how warm the various surfaces in its layers get and why. To get a handle on that we need to be considering the impedance (emissivity) of the layers and surfaces, and why they are what they are.

The reasons atmospheric pressure of 1 bar raises Earth’s surface temperature to an average 289K rather than the ~213K of our airless moon at the same distance from the Sun are several.

Firstly, gravity acting on atmospheric mass sets up a gradient of pressure, which supports buoyant convection. Air leaving the surface and rising to altitude cools adiabatically at the wet lapse rate and air returning to the surface WARMS at the dry adiabatic lapse rate. That warmed air returning to surface reduces the temperature differential between the ground and air, IMPEDING the rate at which conduction of heat from the Sun warmed surface to the air takes place at.

Secondly, the higher the air pressure at the surface, the more the rate of evaporation is IMPEDED. This means the ocean has to rise in temperature until it is warm enough to lose energy at the same rate it receives it, back to the atmosphere and then to space via evaporation, conduction and radiation.

I modified the standard NASA energy balance diagram to try to illustrate and quantify these effects. I welcome comments, suggestions and criticisms to help me improve it.

In this scheme, the pressure gradient in the system is the cause of the higher surface temperature. This doesn’t conflict with the mainstream observations of the levels of radiation occurring at various altitude. In fact, it gives an explanation for them the standard greenhouse theory can’t. Those radiation levels are what they are because of the temperatures the various surfaces and layers of the system reach due to the atmospheric pressure. They are the EFFECT, not the CAUSE of the temperatures. As I was always taught in my physics classes; Everything radiates according to its temperature.

As Ned has previously pointed out, the standard radiative greenhouse theory has no way to explain how 240W/m^2 of incoming Sunlight can be converted into 340W/m^2 of ‘back radiation’ in a freely convecting atmosphere. It is the standard theory which is breaking the energy conservation law, not Ned and Karl.

via Tallbloke’s Talkshop

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September 2, 2019 at 03:15PM