Why the greenhouse gas effect is never disasterous

All matter, above absolute zero temperature, emits photons of energy as electromagnetic radiation, EMR. Colder the matter - the longer the wavelength and less energetic its EMR

The greenhouse gas effect, GHGE relies on idea that only greenhouse gases such as: CO₂, and H₂O absorb and emit EMR. It's true that CO₂ and H₂O absorb more (than non-GHG such as N₂) at specific frequencies. It's untrue that O₂ and N₂ do not emit.

We're often shown a diagram which reveals the EMR absorption spectra of the greenhouse gases seen form space. They say these gases 'trap heat'.

What actually happens is: after photons are absorbed by CO₂, an electron is excited to a higher energy orbital. Now comes thermalization: long before the electron will naturally decay, the molecule will collide with another air molecule such as O₂, or N₂. The excited CO₂ orbital decays and the energy transferred as kinetic energy (to O₂, or N₂) which means N₂ or O₂ speed up slightly. They gain kinetic energy, which can be measured as a temperature increase

. So the energy is shared among all air molecules.

In the 'classical' GHGE hypothesis O₂ and N₂ do not emit. In reality, all matter emits EMR : so the characteristic spectrum is seen from space (see diagrams above). Some energy bands are in deficit (due to GHG), but other bands compensate and are in excess (of EMR emission) compared to what they'd otherwise give (due to extra emission by air). The more CO₂ - the more thermalization - the more O₂ and N₂ will emit. It's important to remember that emission happens according to the 4th power of temperature. Even a small rise in temperature causes a much larger rise in photon energy emission. In short. The claim for a GHGE 'trapping heat' is based on an assumption that this GHGE makes the atmosphere more opaque to infra-red. That does not happen. It has never been observed. There is no evidence for many fundamental assumptions of the GHGE.

The only way a GHGE can warm the surface (in practice) is by ocean heating (which is 90%+ of climate warming). Because the heat capacity of water is 4 times greater than air and there is 270 times more ocean by mass than air. Ocean heating has happened at about 0.001 °C per year. Only 0.1 °C per century at most. But is not continuous. Oceans warm and cool. I'm nor ruling out faster warming than this. But faster warming is more likely in a colder earth. Earth is now in a mid-glacial called the holocene. When it's already warm, the maximum rate of warming will be slower than when earth is cooler. This is why the D-O events are ice age phenomena.

Note:

• The main CO₂ band is 14992 nm = 667 cm^–1
  N₂ emission band is 557.7 nm = 1793 cm^–1
  So the N₂ emission band radiates more energetic radiation than CO₂. It is on the borderline of the red light spectrum sitting in the same infrared area as radiation emitted from the sun. That may explain why this N₂ emission band is often missing from diagrams of the IR. It is too far to the right in the diagram above and was truncated.
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