Archives par mot-clé : GHG

climate-debate

New Study: A ‘Thought Model’ Saying There’s A 33 K ‘Natural Greenhouse Effect’ Is ‘Meritless’ Assumption

by K. Richard, Dec 26, 2022 in NoTricksZone

The conceptualization of a 33 K warmer Earth due to the presence of water vapor and CO2 (greenhouse gases) in the atmosphere is wholly based on the unobserved and unknown, or assumptions about what an imaginary world with no atmosphere would be like.

It is widely believed that we can determine the effective radiating temperature, a uniformly global temperature, the globally uniform albedo…of a rocky planets simply by conjuring up thought experiments about what a made-up world would be like if it did not have an atmosphere (e.g., no N2, O2, atmospheric pressure, clouds, water vapor…).

This “thought model” has been subjected to critical analysis in a new paperpublished by four atmospheric physicists.

…

 

Image Source: Kramm et al., 2022

The authors use observational measurements from 24 datasets for the moon — which actually is the closest real-world proximity to a rocky planet without an atmosphere — as their testbed. They conclude that the globally averaged surface temperature is necessarily “about 60 K” lower than the effective radiation temperature, rendering the “thought model” presumptions about a 33 K “greenhouse effect” differential for the effective radiating vs. global average temperature (255 vs. 288 K) “meritless.”

Other instances of a disqualifying contrast between observations and modeled assumptions include:

…

better to know...?, climate-debate

What If Real-World Physics Do Not Support The Claim Top-Of-Atmosphere CO2 Forcing Exists?

by K. Richard, Dec 22, 2022 in NoTricksZone

…

 Schneider et al., 2020, NASA, UCAR, CGA

TOA greenhouse gas forcing is a fundamental tenet of the CO2-drives-climate-change belief system. And yet the “global-mean longwave radiative forcing of CO2 at TOA” (Schneider et al., 2020) may not even exist.

It is easily recognized that water vapor (greenhouse gas) forcing cannot occur above a certain temperature threshold because water freezes out the farther away from the surface’s warmth H2O goes.

According to NASA, the TOA is recognized as approximately 100 km above the surface. The temperature near that atmospheric height is about -90°C.

CO2 is in its solid (dry ice) form at -78°C and below.

Therefore, TOA CO2 radiative forcing cannot exist if CO2 cannot be a greenhouse gas at the TOA.

climate-debate

The Greenhouse Effect In A Water World

by B. Irvine, May 17, 2021 in WUWT

A knowledge of Greenhouse gases is fundamental to any understanding of global surface temperatures. The presence of GHGs in our atmosphere has increased the global surface temperature by about 33C.

There are multiple lines of evidence, however, that challenge the strong water vapour feedback to a small initial CO2 forcing.  These strong positive feedbacks are central to the IPCC narrative.

These lines of evidence include.

  • The failure of all models and catastrophic warming projections.
  • The stubborn refusal of atmospheric Precipitable Water Vapour (PWV) concentration to rise in recent years.
  • The strength of convection cells in the tropics that have kept tropical temperatures approximately the same for many millions of years.
  • Irrigation and extra humidity generally coincide with cooler temperatures.
  • The hot spot as a signature of the positive Water Vapour (WV) feedback and its opposite, the negative lapse rate feedback, has not occurred.

INTRODUCTION

…

climate-debate

The IR absorptive characteristics of “greenhouse” gases–David Coe

by P. Homewood, Jan 17, 2021 in NotaLotofPeopleKnowThat

SUMMARY

Using well documented data on the infra-red absorption spectra of atmospheric gases it is a straight-forward process to infer the overall atmospheric IR absorption and from that the effective global average temperature. The simplest of atmospheric models has been used: the atmosphere is considered to be a uniform thin absorbing layer of gas. The results demonstrate clearly that the warming effect of the atmosphere is almost entirely due to the spectral absorption characteristics of CO2 and H2O. They are both exceptionally strong absorbers of infra-red radiation. It is however this strength which determines the characteristics of the earth’s temperature, and in particular its stability.

70% of the energy radiated from the earth is removed by a mixture of 0.1% H2O and 200ppm of CO2. This alone is sufficient to raise global temperatures from the chilly 255K of the estimated zero atmosphere condition to 284.3K, less than 4deg below current average temperatures. An estimation of the current atmospheric mixture of gases is calculated to deliver a global mean temperature of 286.8K close to the best estimate of 288K for that temperature. Further increases in both H2O and CO2 have relatively small impacts on temperatures. This is due simply to the fact that at current concentrations the spectra of both H2O and CO2 have effectively extracted most of the energy at wavebands corresponding to their molecular absorption spectra. There is little further energy to be extracted by adding more H2O and CO2. This results in climate sensitivity values of less than 0.5degC, in comparison to the 1.5 to 5 degC range quoted by the IPCC.

CO2 levels of 3000ppm will only raise temperatures by a further 1.5K. These temperature increases are in fact well within natural variations seen in the past, including the medieval warm period and the little ice age of some 300 years ago.

The possibility of positive feedback from water vapour is discounted by the simple fact that the H2O spectrum is incapable of absorbing significant further amounts of radiated energy and the modest increase in temperature due to increasing CO2 levels is unable to deliver any significant increase in H2O concentration due to the specific relationship of H2O saturation vapour pressure and temperature. It would take an increase in temperature of 10degC to double the mean H2O atmospheric concentration, and that doubling would only result in a temperature increase of 2degC.

The impact of other known “greenhouse’ gases, CH4 and N2O are also calculated from known IR spectra data. Their absorption spectra are swamped by H2O and CO2. The combined warming caused by current atmospheric concentrations will elevate temperature by only 0.2K and increasing concentrations by a factor of 10 will only result in a further temperature increase of 0.5K.

The “greenhouse effect” is dominated by the absorption spectrum of H2O with a little help from CO2. At current concentrations of both gases it is inconceivable that further increases in concentrations will lead to any significant warming. Increasing CO2 concentration to 3000ppm and doubling the mean H2O level to 2% would result in a global temperature increase of 3.4K.

In short, there is no climate emergency, at least due to “greenhouse gases”.

 The full paper can be read here:

co2-the-miracle-molecule-22637

…

See this Addendum