CO2 holds onto the infrared radiation long enough to warm.

“Carbon dioxide () is one of the greenhouse gases. It consists of one carbon atom with an oxygen atom bonded to each side. When its atoms are bonded tightly together, the carbon dioxide molecule can absorb infrared radiation and the molecule starts to vibrate. Eventually, the vibrating molecule will emit the radiation again, and it will likely be absorbed by yet another greenhouse gas molecule. This absorption-emission-absorption cycle serves to keep the heat near the surface, effectively insulating the surface from the cold of space”-

The claim has been made that the CO2 molecule immediately reemits the photon so any warming is quite minor. I am of the opinion ucar has it correct above. CO2 holds onto the infrared radiation long enough on average to warm.

Animation of a CO2 molecule here:

“Molecules of carbon dioxide (CO2) can absorb energy from infrared (IR) radiation. This animation shows a molecule of CO2 absorbing an incoming infrared photon (yellow arrows). The energy from the photon causes the CO2 molecule to vibrate. Shortly thereafter, the molecule gives up this extra energy by emitting another infrared photon. Once the extra energy has been removed by the emitted photon, the carbon dioxide stops vibrating –

Ucar says some things above. It does keep the heat near the surface and the CO2 molecule holds the photon for a short time and also uses the phrase, “Eventually, the vibrating molecule will emit the radiation again”. What about water vapor? I think of water and water vapor as an ideal heat storage medium. It absorbs well enough and holds well enough to have many uses for us and the planet. Soil also absorbs, and stores heat. We don’t see instant re-emission with these.

Ira Glickstein writes:

“This frame and the next two illustrate another way Photons are emitted, namely due to collisions between energized GHG molecules and other air molecules.”

It is implied that they hang onto the photon long enough to interact with their neighbors, and that the collisions transfer heat.

I’d like some scientists who work in the area to clarify the situation for the rest of us, and I am still thinking the instant re-emission argument will not hold up.

There is also this:

The Random Walk Problem. Even at the speed of light there’s a delay.



Atmospheric CO2 insulates the atmosphere from ocean warmth

The below is part of some comments I made at Climate Etc to JCH and Jim D:

CO2 density is higher than before above the oceans. The ocean emits a photon that hits CO2 a higher percentage of the time. Half the time when the CO2 emits the same photon it ends up back on the surface of the ocean. If it misses the ocean it may later still end up back there after some more jumps. I suppose that assuming a random direction the photon migrate to places with less GHGs. Upwards I suppose. They can make longer jumps on average into less dense areas. So it seems that the additional CO2 can swat the photons more effectively back into the ocean. The more CO2, the more the oceans are slowed with their LW photon emissions. The oceans are a very important source of warmth. On the other hand since the surface is warmer it can emit more than before, perhaps canceling CO2s swat back enhancement. And on one more hand, I suppose the photons can travel downwards through the water. I am assuming photons on the ocean surface radiate in all directions.

I just checked out RealClimate on the question. It is now more difficult for photons to escape the ocean on average. The oceans are storing heat they receive as short and long wave. However shortwave has been pretty flat. So we are looking at primarily the change in longwave IR. Most of it attributed to GHGs. Assuming for long periods of time 90% of the warming is going into the oceans what is going to reverse that? We could assume in 1950 0% of the warming was going into the oceans, or if not, go back to 1850. This thing as explained at RealClimate, why would it stop? The CO2 will be around keeping more heat in the oceans. Yes it is possible and ocean circulations do change and that could change things. Jim D you said something about reaching a balance. So the oceans need to gain heat to restore the balance, and then we’ll be at equilibrium. In doing so they are going to have to save some heat for themselves. Which leaves me thinking they will do that. Taking the same watts as they did in 1950 and releasing less of them to the atmosphere.

Peter Minnett at RealClimate has an article that has a diagram that says more heat remains in the upper oceans. There is a new temperature gradient across the skin layer. So the balance needs to be restored by emitting less LW photons to the atmosphere. On average and all other things being equal, atmospheric CO2 insulates the atmosphere from ocean warmth. However, sea ice gains or losses are not considered.

Additional commet of mine added 2/09/17:

It occured to me that if we take the instant reemission of energy from the skin layer as a given which a do not, we have increased evaporation and increased salinity. A kind of instant evaporation suggested leaves behind salt which make the warmer water heavier which makes it sink more than before. Warmth moved further from the surface would make the oceans a bit warmer as there is less joules emitted to the atmosphere with that.

Spectrum of GHG Radiation


“Figure 5: Spectrum of the greenhouse radiation measured at the surface. Greenhouse effect from water vapor is filtered out, showing the contributions of other greenhouse gases (Evans 2006).” – from SkS

This is one of the fingerprints of global warming according to some. The above is IR returning to earth. Most of it from CO2 and methane is also significant. In a discussion of this being a fingerprint it occurred to me that water vapor would also be a very good fingerprint. Incredibly strong evidence of the expected increase in water vapor.


Figure 4: Change in spectrum from 1970 to 1996 due to trace gases. ‘Brightness temperature’ indicates the equivalent blackbody temperature (Harries 2001). – from SkS

Water vapor is missing from the above.


brandonrgates points out my mistakes here:

Week in review – science edition



The IPCC versus CPAs

Equilbrium Climate Sensistivity (ECS) is how much warming you get for a doubling of CO2.

“Likely – > 66% probability”

“the ECS is likely between 1.5°C and 4.5°C” – IPCC

What we have is  large error bars that are not useful for helping decision makers. Here is what a CPA says, We are 95% confident the net worth of the company is within 5% of what the balance sheet says it is. See how narrow that is? You can do something with that like make decisions with money. What if the CPA said, we are 66% confident the net worth of the company is from $1.5 billion to $4.5 billion. The CPA isn’t saying anything useful. And he should not be paid and you not should not make decisions based upon what they said. We can see in one case certainty. We see in the other case much less certainty.

Reconciling Sensitivity and Attribution

Looking at something else and finding myself here:

The 50-50 argument

I decided to try to reconcile two things from the IPCC.


“Likely > 66% probability”

“the ECS is likely between 1.5°C and 4.5°C” – IPCC


“Extremely likely > 95% probability”

“It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together.” – IPCC

With sensitivity we have X to 3X with 66% certainty.

With attribution we have roughly Y to 2Y with 95% certainty.

The question is, does sensitivity drive attribution? As you can see the range seems to tighten as we move to attribution. 66% says to me we could be wrong. 95% says we’re right. It’s at the financial audit level of confidence.

What if we do this? Take their attribution as a given. Now work backwards to determine sensitivity. The Sensitivity numbers might tighten up.

I will try to do this using simple math.

1950 assumed to be CO2 310 ppm.

2010 pretty close CO2 385 ppm.

A 24% increase.

From an IPCC chart, the increase in C was about 0.5 C.

From the attribution statement, we caused from 0.25 C to 0.50 C temperature rise. I rounded away from 51% and 99%.

So we may have, half of what happened, 0.25 C to all of it, 0.50 C from a 24% increase. Rounding to a doubling of a 100% increase, we just multiply by 4. So we may have 1.0 C to 2.0 C for a doubling of CO2.

I have attempted to use the attribution of the IPCC to drive the sensitivity value. I decided to use what they are more certain about to shed light on what they are less certain about. I’ve used simple math. 4 times 24% may not equal 96% or 100%. I have some concerns about a log scale.