THE FLAW IN ANTHROPOGENIC GLOBAL WARMING THEORY
My article on “Greenhouse Confusion” drew vigorous comments from those who believe firmly that anthropogenic global warming (or rather climate change) is a real and immediate threat.
It seems that additional infrared or long wave radiation is supposed to have some property that makes it a threat. Thus we hear so much about ‘down welling’ re- radiation from the atmosphere warming up the planet dangerously because humanity is releasing a certain amount of CO2 that would not otherwise be in the atmosphere.
1) The proposed process:
It seems that those who fear AGW (or at least some of them) do admit that it is not realistic to expect a planetary atmosphere such as ours to warm up oceans of water over the timescale required by AGW theory because of the huge volume and density of that water and thus the heat storage differentials. Water will cool air very effectively but the heat energy drawn from the air makes virtually no difference to the temperature of the water.
When I say heat storage I am aware that the heat energy is not ‘trapped’ in either atmosphere or ocean, merely that varying amounts of solar heat energy are delayed in the process of transmission through the ocean/atmosphere system. I explained that more fully in my “Greenhouse Confusion Resolved” article.
I have previously explained how it is the oceans via “The Hot Water Bottle Effect” that control the temperature of the atmosphere and not the greenhouse effect so that if we are to get a warmer atmosphere we have to first negate the cooling power of the oceans (and vice versa). My contention is that warming up enough of the entire body of the oceans would take millennia if it were possible at all and not just a couple of decades as feared by some. Some idea of the relative scales of “The Hot Water Bottle Effect” and “The Greenhouse Effect” is given in the pictures at the head of this article but even there the larger scale of THWBE is massively reduced.
To deal with the problem of getting the oceans to warm up a mechanism has been proposed by Realclimate on this link:
They start by linking the increasing heat content in the oceans to the observed increases in GHG’s, especially CO2, in the atmosphere. However they leave out the fact that solar activity has been very high for the past 50 years in relation to the past 400 years. They also fail to mention that sunlight can travel tens of METRES into the water and is thus a powerful warming agent compared to the single MILLIMETRE penetration of down welling infrared radiation from the atmosphere.
They also fail to mention that although the incoming solar radiation only varies by a couple of Watts per square metre over a solar cycle the apparent smallness of the variation is a result of the small area subdivision and not any indication of a small total energy variation when one takes into account the number of square metres on the Earth’s surface. They also fail to appreciate that because solar radiation was at a historic high during the period in question it likely follows that there was a net solar warming of the oceans throughout the period even though the rate of solar radiation was on average stable during that period.
However for present purposes I will ignore all that and take at face value the assertion that increased CO2 caused the oceanic warming.
They have to explain how infrared radiation reflected back downwards from extra greenhouse gases would, over time, add a significant amount of extra heat to the oceans. The definition of ‘significant’ is important. If it takes a thousand years or more then there is no current threat. By the time we get an impact from anthropogenic climate change then humanity’s problems will have been solved or our civilisation will have been destroyed by other problems such as pollution, resource depletion or overpopulation.
If the AGW threat is to be taken seriously it has to warm up much of the entire body of all the world’s oceans in two or three decades.
The idea seems to be that the extra returning infrared radiation has to work it’s evil through the top millimetre of ocean surface. That is not a misprint. Infrared radiation can only affect the top millimetre.
In contrast solar energy penetrates up to 100 metres so one can see which is going to be the major influence on oceanic temperatures as far as input is concerned.
It is proposed by Realclimate that the extra down welling infrared radiation warms up that top single millimetre layer (they call it the ocean ‘skin’) a tiny bit and apparently that is enough to disrupt the worldwide flow of heat energy from ocean to air to space with the result that the oceans release incoming solar energy more slowly so that heat builds up in the oceans.
Where is the evidence that that it is true in the real world?
2)Problems for the Realclimate theory (and it is only a theory).
i) It is well known that the oceans have warmed since 1960 and that since then the sun has been at a historic high in activity. It is also accepted that warmer oceans hold less CO2. Those three facts suggest that most if not all of the observed increase in CO2 is natural unless it can be shown that for some reason warming oceans can nevertheless act as a carbon sink rather than a carbon source. I know that attempts have been carried out to do that and anyone interested will no doubt find such attempts elsewhere on the Realclimate site. I am not convinced. Warmer oceans overall hold less CO2 overall and no mechanism has been found to falsify that proposition. Thus we really do not know what proportion of the CO2 increase is caused by human activity. I have seen suggestions that it was all of it, one third of it and one tenth of it. None of those speculations are capable of proof at present.
Furthermore the entire biosphere is energised by extra warmth and the whole carbon cycle speeds up with extra warmth from sun or oceans without any need to invoke human involvement at all. Such increased biosphere activity mops up any increase in CO2 and might well be enough, over time, to absorb much if not all of our production of extra CO2.
All I have seen from the AGW lobby on this issue is a denial that the sun had any effect during the past 50 years because it’s output was ‘stable’. I pointed out in my article entitled “The Death Blow to AGW” that stability is no indication of an absence of accumulating solar energy in the Earth’s system if the sun was at a historically high level of activity as it then was. There is therefore substantial evidence that the CO2 increase observed has been mostly natural. That is supported by a very recent observation that the rate of rise in CO2 seems to have been affected by the recent cooling of the Pacific. It is too early to be sure but that needs watching because it may reveal a stronger than expected correlation with oceanic temperatures rather than human output of CO2.
ii) Can the top millimetre of a vast ocean really have any effect on the overall net movement of heat energy from ocean to air to space? Realclimate theorises that it could affect the temperature gradient from the body of the ocean to the surface ‘skin’ and thereby slow down heat loss from the oceans to build up more heat in the entire system but do we know that the effect is significant in the real world or is it just a desperate guess intended to try and prop up the AGW theory? The oceans are not motionless. They are in constant and often violent movement. Surely it is much more likely that any effect on the surface ‘skin’ will be broken up by all that movement?
Much more likely that the surface ‘skin’ will be almost immediately incorporated into the main body of water and the ocean to atmosphere flow continues as if nothing had happened. The use of the word ‘skin’ is misleading because that implies some sort of physical barrier whereas oceanic movement and mixing will ensure that there is none
iii) So, what if all that extra re-radiation warms up the surface ‘skin’ of the ocean without immediate mixing but only to a depth of one millimetre. What really happens next? It seems obvious to me that one has also increased the temperature differential between ocean surface and the atmosphere. Such a change will accelerate the flow of heat energy from the ocean surface to the atmosphere and offset any warming of the ‘skin’ from any extra CO2 caused by humans. Effectively, the water surface is sufficiently impermeable to infra red radiation to simply bounce or reflect it back up into the atmosphere again without any significant effect on the temperature of the water or the net natural flow of energy from ocean to air to space (and it is always in that one way direction only). Realclimate only mentions half the equation. They ignore the increased ocean/atmosphere differential.
iv) The downward infrared flux from the atmosphere to land surface or ocean is primarily natural so that the near surface temperature already accommodates that natural component. The size of any extra human component is entirely speculative because we currently have no way of knowing what proportion of the CO2 increase is human as against natural. The figures you will hear depend entirely on the prejudice of the person supplying them. Furthermore natural global temperature swings alter the natural background greenhouse effect constantly as water vapour held in the atmosphere increases and decreases naturally with changing global temperatures. Those water vapour swings have changed the power of the greenhouse effect many times over the millennia, far more than CO2 is expected to, yet no tipping point has ever been crossed.
v) The scale of natural variation. The recent La Nina episode combined with a quiet sun has almost wiped out the warming observed over the past 20 years in a period of less than 2 years. Admittedly we may bounce back but at this moment it is not looking likely. For myself I would like to see a cessation of the current cooling because cooling is so much more dangerous than warming. Various predictions have been made by AGW supporters that we will bounce back to warming in 2010, 2015 or 2020. The Hadley Centre predicted 2010 not long ago and I wonder if they would now like to adjust that suggestion given that they have less than 18 months to go.
For all the above reasons the Realclimate theory is simply not sufficiently plausible and I see no credible means as to how AGW can warm up the oceans fast enough to be a threat in the foreseeable future. Given that human emissions of CO2 were not very substantial until after WW2 I cannot see how human GHGs could have contributed quickly enough or significantly enough to the observed warming of the early and late 20th Century.
3) The more likely truth.
Evaporation and Condensation as a global heat energy removal system combined with planetary weather systems that involve convection, winds, clouds and precipitation. Those combined processes constitute the hole in the heart of all climate theory because thus far it has not been possible to collate the actual real world numbers for all those processes in order to make meaningful use of all of them in any models.
Those processes must be critical but are not mentioned by Realclimate at all. The conversion of a water molecule to a water vapour molecule involves a huge energy transfer from water to air so evaporation alone is a substantial factor.
Evaporation cools the water substantially (yes it cools it- so much for the water getting warmer!) due to the Latent Heat of Evaporation but does not significantly warm the air because the heat energy is held by the water vapour (hence ‘latent’). The air with it’s water vapour is quickly taken away by winds and convection and rises to higher levels in the atmosphere. When it reaches a level high enough to cool it to it’s ‘dew point’ the water vapour condenses out in the form of clouds and rainfall and the Latent Heat of Condensation is released into the upper part of the atmosphere to accelerate the escape of radiant energy to space.
The process of such evaporation and then condensation together with those other weather processes is an express route to get heat energy from ocean to surface to atmosphere to space and the bigger the temperature differential between ocean surface, atmosphere and space the faster they must all work to move the atmosphere back towards a temperature equilibrium. So even if increased infrared radiation caused by man does try to warm the surface of the oceans those processes will increase immediately and neutralise at least the majority of any extra warming from additional down welling anthropogenic infrared radiation. We have the benefit of a variable natural atmospheric heat pump. A negative feedback process of considerable power not mentioned or quantified at all in AGW theory. Indeed enhanced evaporation of water vapour into the atmosphere is conventionally regarded as an aggravating factor because water vapour is itself a greenhouse gas (see below about that).
If extra human CO2 does warm the top millimetre of the ocean a little before the extra down welling infrared radiation is bounced back up by the almost impermeable ocean surface then the air immediately above the ocean surface will promptly warm up. Warmer air holds more water vapour so that warmer air will extract more vapour from the ocean surface thereby cooling the ocean surface.. The Realclimate theory thus fails and the temperature gradient from the body of the ocean to the top millimetre and then the atmosphere is maintained at or near to the natural level with the extra warmth being ejected from the system by the enhanced evaporation/condensation and weather processes.
Any evaporation removes from the ocean much more heat energy than one would expect because of the large energy value of the Latent Heat of Evaporation. That property of water could be enough to enable the weather processes overall to stabilise the whole process and is one of the reasons why oceanic temperature is, always has been and always will be the primary atmospheric temperature driver and will always reduce or possibly neutralise any effect of an enhanced greenhouse effect in the absence of really huge changes caused by astronomic or geological processes.
I do know that water vapour itself being a greenhouse gas additional evaporation is often said to ADD to the warming effect and not reduce it as I have suggested. However that ignores the condensation part of the cycle and all the aspects of weather. In reality the initial evaporation removes heat energy from the ocean. A short while later, maybe a week or so, the subsequent condensation working with weather processes injects the extra heat energy into a higher level of the atmosphere (often very much higher) from where it can be more rapidly radiated to space.
All the descriptions of the evaporative process that I have seen so far concern themselves just with the evaporative and precipitation aspects as part of the hydrological cycle and ignore the condensation part in so far as it releases heat energy higher in the atmosphere for faster radiation to space. For present purposes we should be considering the entire weather system as a global heat energy transport and disposal system. The faster it works the more heat energy is removed. Unfortunately science has not yet got an adequate grip on the relevant mechanisms, their quantities or the extent of the influence of weather on the whole process and it seems to me that until that part of the climate system is far better understood and quantified we should not be making speculations as to how other changes such as more CO2 will affect the climate system overall.
If it is correct, as I have read, that water vapour taken into the atmosphere takes about a week to return as precipitation then that implies that on average the entire atmosphere turns over 52 times in every year. The process amounts to a heat pump with a frequency cycle of 52 full cycles per annum producing a continuous flow of outgoing heat energy. Now that is a mechanism one cannot overlook. Even a small change in such a mechanism would dwarf by far any changes from most other sources and it appears that more warmth just accelerates it because of the increased temperature differential between surface and space. AGW would self cancel by accelerating the heat disposal mechanism virtually instantly.
We need to look at the evaporative/condensation process combined with ALL aspects of global weather as an ever changing global heat energy removal system and not just as a part of the hydrological cycle as usually set out in models and schematic diagrams. Furthermore I often see the evaporative process set out on it’s own as an averaged figure for the whole planetary surface whereas the land and ocean surfaces would have very different characteristics. Additionally the oceanic warming and cooling cycles introduce constant, rapid and substantial changes not yet reflected in any models and which invalidate any averaged global estimates of the planetary heat budget. The behaviour and influence of weather as part of the global heat energy redistribution system is ignored or reduced to meaningless averages because we have so little numerical information about it and I believe that is where our current theories and projections fail.
That could explain the resolute failure of real world observations to match model expectations and the failure to appear of the anticipated tropospheric ‘hot spot’ that was expected as a marker for AGW.
Global weather processes involving evaporation and condensation and the heat transfers involved in those processes could be sufficient to redistribute and eject from the system the relatively small amount of extra warmth from an enhanced greenhouse effect as fast as it forms. In contrast those systems cannot adjust quickly enough to cope with the truly huge changes involved in solar and oceanic variations so it is those which will control the overall system whatever humanity does or does not do. However it does seem that over enough time even those larger variations do get neutralised by the system much of the time otherwise Earth would not be as stable as it seems to be between major ice age scale climate shifts.
The truth is that our influence is as nothing compared to natural forces and if Realclimate and others wish to be believed and trusted then they have much work to do and should not expect to be able to spread panic and dismay worldwide on the basis of the inadequate evidence currently available.Published by Stephen Wilde August 6, 2008