Written by Stephen Wilde
The Death Blow to AGW
Wednesday June 04, 2008 9:46 AM BST
Stephen Wilde has been a Fellow of the Royal Meteorological Society since 1968. The first five articles from Mr Wilde were received with a great deal of interest throughout the Co2 Sceptic community.
In Stephen Wilde’s sixth and exclusive article for CO2Sceptics.Com he considers that the IPCC have failed to carry out any risk analysis for the potential for global cooling instead of global warming and that a repeat of the Little Ice Age a mere 400 years ago would cause mass starvation worldwide.
The Death Blow to AGW by Stephen Wilde
The influence of the sun has been discounted in the climate models as a contributor to the warming observed between 1975 and 1998. Those who support the theory of anthropogenic global warming (AGW), now known as anthropogenic climate change so that recent cooling can be included in their scenario, always deny that the sun has anything to do with recent global temperature movements.
The reason given is that Total Solar Irradiance (TSI) varied so little over that period that it cannot explain the warming that was observed. I don’t yet accept that TSI tells the whole story because it is ill defined and speculative as regards it’s representation of all the different ways the sun could affect the Earth via the entire available range of physical processes.
Despite the limitations of TSI as an indicator of solar influence I think there are conclusions we can draw from the records we do have. Oddly, I have not seen them discussed properly anywhere else, especially not by AGW enthusiasts.
This link shows the pattern of TSI from 1611 to 2001.
It is true that, as the alarmists say, since 1961 the average level of TSI has been approximately level if one averages out the peaks and troughs from solar cycles 19 through to 23.
However, those solar cycles show substantially higher levels of TSI than have ever previously occurred in the historical record.
Because of the height of the TSI level one cannot simply ignore it as the IPCC and the modellers have done.
The critical issue is that having achieved such high levels of TSI by 1961 the sun was already producing more heat than was required to maintain a stable Earth temperature. On that basis alone the theory of AGW cannot be sustained and should now die.
Throughout the period 1961 to about 2001, there was a steady cumulative net warming effect from the sun. The fact that the TSI was, on average, level during that period is entirely irrelevant and misleading.
It is hardly likely that such a high level of TSI compared to historical levels is going to have no effect at all on global temperature changes and indeed during most of that period there was an enhanced period of positive Pacific Decadal Oscillation that imparted increasing warmth to the atmosphere. My link below to article 1041 contains details of my view that the sun drives the various oceanic oscillations which in turn drive global temperature variations with all other influences including CO2 being minor and often cancelling themselves out leaving the solar/oceanic driver supreme.
It could be said that the increase in TSI from a little over1363 to a little under1367 Watts per square metre over the 400 year period shown is pretty insignificant. However a square metre is a miniscule portion of the surface of the planet so that even a tiny increase or decrease in the heat being received on average over each such tiny area translates into a huge change in total heat budget for the entire planet. The smallness of the apparent range of variation is a function of the smallness of the area subdivision used rather than an indication of insignificance. It is fortunate for us that the sun is not more variable.
The observation of a historically high level of TSI from 1961 to 2001 tends to fit with the theories set out in my other articles about the real cause of recent warming and the real link between solar energy, ocean cycles and global temperatures.
Amongst other things the above link (2) shows how the negative PDO from 1961 to 1975 cancelled out the warming effects of solar cycles 18 and 19 and led to a cooling trend during those years despite the relatively high TSI levels. The switch to a positive PDO from 1975 to 2001 allowed the solar warming influence to resume. We now have both a falling TSI and a negative PDO which is an entirely different (indeed opposite) scenario to the one which led to the concerns about runaway warming.
If the current scenario continues for a few more years then real world observations will resolve most of the disputed issues. For the past 10 years the real world has been moving in the direction predicted by the solar driver theory and in my articles I have described the oceanic mechanism that transfers solar input to the atmosphere and then to Space.
If global temperatures were to resume warming despite a reduction in solar activity and/or a negative PDO then the alarmist position might be vindicated. The alarmist camp is predicting such a resumption of warming. The Hadley Centre suggested 2010 but others have more recently suggested 2015. If there is no resumption of warming by 2015 then AGW is dead as a theory. It would not count in favour of AGW if any resumed warming were accompanied by increased solar activity or a positive PDO because that would put the solar driver back in control.
My own view is that there is plenty of evidence currently available that should demonstrate from an objective viewpoint that the theory of AGW is already dead, namely:
1) Real world temperature observations which are diverging from model expectations more and more as time passes
2) The clear recent decline in solar activity
3) The return to a negative (cooling) Pacific Decadal Oscillation) which may last 30 years on past performances
4) A change in global weather patterns which I noticed as long ago as 2000 whereby the jet streams moved back towards the equator from the positions they adopted during the warming spell. The observation that a global warming or cooling trend can be discerned from seasonal weather patterns seems to be unique to me and will be dealt with in more detail in my next article.
Those who still believe in AGW have to be able to show that any CO2 driver is powerful enough to seriously disrupt the solar driver. If all that the CO2 does is to marginally raise global temperature over the period of a natural solar driven warming and cooling cycle then there is nothing to fear because the mitigating effect in cool periods will outweigh any discomfort from the aggravating effect at and around the peak of the warm periods.
In fact, it is possible that even the extra warmth around the natural warm peaks will be entirely beneficial.
There are other interesting implications to be drawn from the TSI history referred to above.
Applying a little logic it must be the case that at a certain level of TSI the global temperature budget will be balanced i.e. neither warming nor cooling. During the 400 years since the world experienced the relatively low TSI levels of the 1600’s that point of balance must have been crossed and re crossed many times as the TSI numbers varied with time. That is why the world has experienced warming and cooling spells regularly over the centuries (though with an average warming trend since 1601)
As it happens the chart shown covers TSI from the depths of the Little Ice age to the recent warm spell so it is clear that the point of transition from net cooling to net warming is somewhere within the range 1363 to 1367 Watts per square metre. Indeed on the basis of just a brief glance at the chart that point of transition is obviously lower than the average TSI between 1961 and 2001 hence my assertion that during those years there was a steady solar warming effect which adequately explains the observed warming without reliance on rising CO2. This is such a simple and obvious point that I really do not understand why the IPCC and the modellers did not see it.
The information that we need and which is critical to the whole global warming debate is some idea of the level of TSI at which the Earth switches from net warming to net cooling. It will be hard to identify because, as I have mentioned in my other articles, the filtering of the solar signal through the various oceanic cycles is neither rapid nor straightforward.
In fact that point of transition will itself vary over time depending on whether, at any given moment, the oceanic cycles are working against or in support of the TSI changes. Similarly the speed of response will vary for the same reasons.
I really do not see how any climate model can operate meaningfully without that fundamental piece of information.
Clearly the ‘elephant’ is missing from the room.
Finally, in view of the widespread concerns about the involvement of CO2 I should emphasise that if solar energy is the primary driver of global temperature then the only consequence of a stronger greenhouse effect is going to be a slight upward movement of the prevailing temperature throughout the natural warming and cooling cycles.
Because of the logarithmic decline in the greenhouse warming effect of increased amounts of CO2 there is never going to be enough greenhouse effect from any amount of increased CO2 to overturn the primary solar driver or the regular movements from warming to cooling and back again.
The only ‘tipping point’ we need be concerned with is the level of global temperature at which warming switches to cooling and vice versa. Due to the much greater threat from natural cooling the higher we can lift the global temperature at that tipping point the better. On balance we need more CO2 rather than less.
The band of TSI in which the switch from warming to cooling and back again is a variation of less than 4 Watts per square metre of heat arriving at the Earth’s surface.
In view of the size and volatility of the sun we can be boiled or frozen at any time whatever we do. The only reason the sun seems stable enough for us to live with it is that in relation to astronomic timescales our whole existence as a species is but a flash of light in darkness.
The whole of modern civilisation has been made possible by a period of solar stability within a band of less than 4 Watts per square metre. It will not be a result of anything we do if solar changes suddenly go outside that band. On a balance of probability it is more likely that the TSI will soon drop back from the recent unusual highs but remaining within the band of 4 Watts per square metre. It would need the arrival of the next ice age to go significantly below 1363 but even a reduction down to 1365 from present levels could introduce a dangerous level of cooling depending on where the tipping point currently lies.
A period several decades of reduced solar activity will quickly need more emissions producing activity to SAVE the planet yet nonetheless the populations of most living species will be decimated. At present population levels a repeat of the Little Ice Age a mere 400 years ago will cause mass starvation worldwide. Does anyone really think that the CO2 we produce is effective enough to reduce that risk to zero when we have plenty of astronomic evidence of an imminent reduction in solar activity?
And, moreover, the real world temperature movements are currently a good fit with the solar driver theory both as regards the warming spell, the subsequent stall and the recent turn downwards.
The AGW risk analysis process (if anyone ever bothered with one) is seriously flawed.