Greenhouse effect may be self adjusting due to water vapour and relative humidity adjustment.
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hysicist Miklos Zagoni says, "It is nonsense to think that a system ‘waits’ for our CO2-emissions to elevate its temperature if otherwise the energetic conditions make possible to rise and the necessary resort (a practically infinite reservoir of greenhouse gases in the form of water vapor in the oceans) is at its hands."
Adding some greenhouse gases (CO2) to a near infinite supply of greenhouse gases in the form of water vapour available to the atmosphere has negligible effect.
The new theory implies that adding CO2 to the atmosphere would reduce the relative humidity, contrary to climate model assumptions. So, has relative humidity been falling with increasing CO2 concentrations?
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The paper,Greenhouse Effect in Semi-Transparent Planetary Atmospheres by Ferenc M. Miskolczi shows that the current greenhouse effect equations are incomplete because they do not include the correct boundary conditions. The new theory presented in Miskolczi's paper shows that the atmosphere maintains a “saturated” greenhouse effect, controlled by water vapor content.
Considering that we are told "the science is settled", one would think that the strength of the greenhouse effect (GHE) on Earth would be calculated based on atmospheric physics. That is, the computer models of the atmosphere would incorporate the physics of how the greenhouse effect works, so that by inputing some measured physical properties, the atmospheric gases, the models would determine the strength of the greenhouse effect and the surface temperatures. Unfortunately, this is not the case.
There are no physics, no equations in the models that determines the strength of the GHE. Parameters are just set to obtain the observed temperature.
The GHE is dominated by water vapour, so how it changes with increasing CO2 is critical.
All the General Circulation Models (GCM) or more commonly called Global Climate Models just set
various evaporation and precipitation parameters to achieve approximately the result:
Relative humidity = constant.
This result is based on short term observations of temperature changes while CO2 concentrations were approximately constant, so they only hold true over periods when CO2 does not change much. It is invalid to extrapolate these observations to long term periods with increasing CO2. The modellers just assume relative humidity is also constant while CO2 concentrations change.
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A NASA study from here says:
A NASA-funded study found some climate models might be overestimating the amount of water vapor entering the atmosphere as the Earth warms. They found the increases in water vapor were not as high as many climate-forecasting computer models have assumed. In most computer models relative humidity tends to remain fixed at current levels. "The increases in water vapor with warmer temperatures are not large enough to maintain a constant relative humidity," Minschwaner said.
Dr. Roy Spencer’s article Global Warming and Nature’s Thermostat here , describes the role of precipitation systems in controlling the greenhouse effect. It is an extension of Richard Lindzen’s “Infrared Iris” hypothesis. Dr. Spencer says we don’t know why the greenhouse effect is limited to its current value.
Miskolczi provides the detailed explanation of why the greenhouse effect is limited to its current value for a constant external Sun forcing. Adding CO2 to the atmosphere just replaces an equivalent amount of water vapour to maintain a constant greenhouse effect. This would have negligible effect on global temperatures.
The global warming the Earth has experienced over the twentieth century is mostly due to the Sun, including the Sun’s effects on clouds via cosmic rays. Increasing Sun activity adds to the greenhouse effect by increasing the specific humidity; increasing CO2 concentration in the atmosphere does not. The actual 20th century warming results may be considered the sum of two processes:
1.
Solar forcing increase with constant CO2; plus,
2.
Increasing CO2 concentration with constant solar forcing
1. An increase of the Sun's radiation input net of albedo with no change in CO2 concentrations would cause no change to relative humidity. Global temperatures would increase causing an increase in specific humidity with the greenhouse effect (in W/m2) increasing by one-half of the solar input change (also in W/m2).
2. An increase of CO2 with constant net solar radiation causes relative humidity to fall, especially at the 400 mb and 300 mb level, as this is at the characteristic emission level. Changes of humidity near the surface has little effect on the strength of the greenhouse effect as the high water vapor content already captures most of the long wave-length radiation, so relative humidity would not change much near the surface. The CO2 replaces water vapour to maintain a constant greenhouse effect, so global temperature changes would be negligible.
The sum of these two process describe the 20th century warming results. Specific humidity has increased at lower altitudes, but has decreased at high altitudes. The decreasing relative humidity (especially at 300 and 400 mb levels) almost totally offsets the GHE of increasing CO2 content. The warming was caused by the increased solar forcing amplified by a positive water vapour feedback.
The Sun has recently become quiet resulting in declining global temperatures since 2002 despite increasing CO2 content in the atmosphere.
A summary of the Miskolczi theory by Miklos Zagoni is here.
A four part critique by David Stockwell is here.
Reference:
Ferenc M. Miskolczi, "Greenhouse Effect in Semi-Transparent Planetary Atmospheres", Quarterly Journal of the Hungarian Meteorological Journal, Vol. 111, No. 1, January - March 2007. [Alternate link here.]
Ken Gregory, P.Eng.
Director
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