Part Three Carbon Dioxide and Water sensitivity

In looking at climate change one must look at the greenhouse effect which brings one to water H₂O and carbon dioxide CO₂; although there are other factors they are minimal and can be ignored since H₂O and CO₂ are the main contributors. We know from the previous post in this series that the total Greenhouse effect is 33.4 degrees Celsius and that requires only one assumption and that is that the global temperature is 14.6 degrees Celsius today. We are ignoring the current NASA January 2015 publication for Global temperatures since they are obviously false and the purpose of this series of technical papers is to show why. For the record, NASA states that the Global temperature for January 2015 was 14.94 degrees Celsius (an anomaly of 94). I believe that it is closer to 14.59 degrees Celsius (an anomaly of 59).

The makeup of the 33.4 degrees C of the Greenhouse effect is extremely important in understand climate; therefore the Global temperature. In the previous post where we established the 33.4 degree value for the Greenhouse effect we left the discussion with the problem of how much of that 33.4 degrees C is water and how much is CO₂. To make that determination we need to know both the sensitivity value of water and CO₂.so let’s get into that issue now.

The next Chart shows a plot of some of the debated CO₂ values starting with .65 degrees C the cyan plot and moving up to 1.0 degrees C the light green plot, to 1.5 degrees c the yellow plot, to 2.0 degrees C the orange plot, to 2.5 degrees C the red plot to 3.0 degrees C the dark red plot. The X axis shows CO₂ in ppm and the Y axis is in degrees Celsius. There is a black vertical line at 400 ppm the present level of CO₂ in the atmosphere and another at 500 ppm in purple for what might be expect by 2050. The cyan rectangle is placed on the plot for .65 degrees C value and shows the area of current concern which is between the vertical Back line, where we are now, and where we could be in 35 years. It’s clear the remaining effect of CO₂ with a sensitivity value from .65 degrees C will contribute very little to any future climate change.

The dark red rectangle in the Chart is placed on the plot for a sensitivity value of 3.0 degrees C which what the IPCC uses in their GCM’s. Because of the shape of the curve you can see that there could be a significant additional warming to the planet if the 3.0 degrees C value is correct. According to the IPCC in their Fifth Assessment Report (AR5) issued in 2014 this value (climate sensitivity or CO₂ forcing) is likely to be in the range 1.5 to 4.5 degrees C with a best estimate of about 3.0 degrees C, and is very unlikely to be less than 1.5 degrees nor greater 4.5 degrees C. However there are scientists that think that the CO₂ climate forcing values maybe as low as .4 degrees C. Since the GCM models are very, very sensitive to this number the admitted range of uncertainty is a major problem that sheds doubt to the validity of the GCM models.

But since we already know that the values the IPCC uses were developed in 1979 by the NAS what has happens since then? The next chart shows 28 studies and the range of values that each author believes is the correct value for CO₂ sensitivity that is expected. The older values are on the right and the newer ones on the left except for the NAS 3.0 degree C value which is shown twice once as the NAS in 1979 and the other as the IPCC’s AR5 from 2014 which is shown to the far left since it is still what the IPCC uses; one can see how far off it is from the more current studies.

The range in these studies is from about .02 degree C to 10.0 degree C with an estimated average of around 1.9 degrees C. It’s clear from Chart that 3.0 degrees C is higher than what much of the peer reviewed studies support and in reality values closer to MIT’s Lindzen of .65 degrees C work much better in practice. However whichever it is its surly not certain or there would not be such a wide range of estimates. Also it is very interesting that the trend is down which is significant since with time we normally get closer to the truth rather than further away.

Much of the very wide range of estimates for CO₂ forcing results from the way that solar insolation enters the planet’s atmosphere and how much water is assumed to be in the atmosphere. These are major factors and are not well understood or the range of values would not be what they are. The next Chart shows the incoming and outgoing radiation frequencies involved in calculating the forcing values incoming on the left and outgoing on the right. Also there two absorption bands for CO₂ with a black and red oval around them; in the black one there is one common band with water and one that is not but since there is very little energy there they can probably both be dismissed. Then if we look at the outgoing radiation which is now in the Infrared (IR) we can see there is only one common band shown with the red oval. So the process in question is how much does the CO₂ absorb incoming insolation, if any, and more importantly how much outgoing IR is absorbed and then how much of the re-radiated IR is then absorbed by the water H₂O?

CO₂ is only .04% of the atmosphere and water is .25% overall and has a wide range from almost 0 to 5% so any calculation of what affect CO₂ can have on trapping thermal energy is not an easy task. Complicating this even more is the question of how long does the water hold the heat as it does eventually send it out of the earth’s atmosphere. In my opinion this issue is so complicated that it may not be solvable with complex equations based on physics and chemistry and so a better method might be to back into it from the 33.4 degree value which is close to being reasonable. From geological records we know that the planet has never overheated even when CO₂ was almost 20 times more than it is now at 7,000 ppm or we would not be here. We also know that the IPCC climate models appear to have a runaway positive feedback bias showing global temperatures at levels never experienced on the plant for high levels of CO₂.

So first let’s assume a lower value for CO₂ such as .65 degrees C since it would prevent the runaway heating effect. The next Chart shows a CO2 plot in green based on the .65 degree value. Also shown are two lines the first at 400 ppm where we are now and the second an arrow pointing to the right from the intersection of the curve and the 400 ppm. If this curve is correct then we can expect only another half degree Celsius increase due to Carbon Dioxide even if it doubles to 800 ppm.

What so many people forget when they are discussing the subject of Climate Change or Anthropogenic Climate Change is that the primary greenhouse gas in the atmosphere is Water, just plain old H₂O at .25% or 2,500 ppm. The Carbon Dioxide CO₂ that so many are extremely worried about is only a minor player at only .04% or 400 ppm. The how that these two interact in our atmosphere along with incoming solar radiation and outgoing infrared (IR) is what keeps the atmosphere of the planet 33.4 degrees Celsius warmer than it would be without these two gases. In other words as previously discussed the planet would be an ice ball and probably devoid of life without them.

When studying climate in relationship to Water and the various other trace gases such as CO₂, Ozone, and Methane one finds that there are only a few bands (frequencies) of visible (incoming) or Infrared radiation (outgoing) where the trace gases could affect water which is the repository of the heat making up that 33.4 degrees Celsius of warming as previously shown here   Ozone absorbs ultra violet which is very important to us but does not interact with the water or the Carbon Dioxide in the atmosphere so it can be dismissed for considerations involving changes in global temperature. Methane at present levels is only 1.8 ppm and so even though it could be a factor at higher levels it can also be dismissed for now; and so for all practical purposes that only leaves Water and Carbon Dioxide to consider for changes in the climate with the variations of these gases in the atmosphere.

When we look at the previous Chart of absorption bands it shows the radiation transmitted by the atmosphere or absorbed it would seem that the ratio of absorption of energy by Carbon Dioxide to Water is about 1 to 6 or in other words 16.7% CO₂ and 83.3% H₂O. We know following the logic used here that 5.5 degrees Celsius was the approximate amount of increase in the atmosphere from Carbon Dioxide using a forcing value of .65 degrees C and so if we subtract that from 33.4 degrees Celsius we get a remainder of 27.9 degrees Celsius. That must then be the amount contributed by the water itself to the process and we can make another chart showing the contribution due to water shown next. To make the chart we have water at 2500 ppm and we know the amount of increase in temperature must be 27.9 degrees Celsius so what sensitivity value will produce that curve? This Chart shows that if the sensitivity value of water is approximately 2.45 degrees C than we get the required value to made this logic work.

This process makes sense since if the numbers were reversed and we made Carbon Dioxide have a sensitivity of 3.0 degrees Celsius (as the IPCC claims it is) than the warming from CO₂ would be 26.0 and there would be no room for the water as there would only be 7.4 degrees available for the water. However, since we know the absorption bands of the CO₂ and Water and we know the distribution on energy coming in and gong out we also know that this is not possible.

Therefore the ~.65 sensitivity value must be a close approximation of the actual situation in the atmosphere and the IPCC value that they use of 3.0 degrees Celsius must be wrong.

In the next section we’ll look at Carbon Dioxide (CO2) and see if we can develop an equation to forecast its past and future levels where we need to look at future Global temperatures.