Climate Change –Yes   Carbon-dioxide – No. A regression and polynomial analysis study.  By Dr Chris Barnes Bangor Scientific and Educational Consultants First Published on Internet 19th December 2012


Dr Barnes' Homepage Link




Commonly available climate data are re-analysed in a variety of ways.  Conclusions are reached which support previous finding of the author that the main driver of both positive and much more recent negative global temperature change may be aviation emissions especially contrails .  Pre the jet travel era there appears to be little if any significant warming or CO2 correlation. Warming started in earnest with the now famous ‘hockey stick’ which can be explained by types of aircraft and contrail in use at any given time. 




Most educated people in our world are convinced our climate and our regional weather has changed dramatically in recent years. Carbon mediated anthropogenic global warming is now accepted by many but there remain sceptics and dissenters.     It is also unfortunate that modern interpretations of climate change as presented particularly by the media and IPCC rarely. if ever, refer to the medieval  warming period in which clearly some natural process caused enormous climate warming.       


Recent work of the present author casts a shadow of doubt on the modern day premise for climate warming we have all come to accept.  This author is not the only scientist to add a voice of caution.  This author’s work tends to suggest that it is aviation emissions (especially contrails) not earthbound global carbon emissions that is/has been responsible for the bulk of or possibly all global warming since 1970 and possibly since as early as 1940[1].    



Much has been made of the recent ‘hockey stick’ effect in global temperatures between about 1970 and 2000.  Protagonists of doom would have us believe this is portending of carbon induced runaway warming wherein the entire planet will scorch to death by about 2050.   


The simplest hypothesis we can consider is if global warming is purely down to carbon dioxide there ought to be the observation of  a linear fit between the observed degree of warming and its driver  unless that is a positive feedback process accentuates the warming or a secondary process is responsible all along.    Furthermore many of the known feedback processes have half –lives of hundreds or even thousands of years; thus if sudden changes are observed over a matter of ten or twenty years they are far more likely to be related to a secondary driver than a feedback effect.     


A secondary hypothesis would be to consider what happens before the ‘hockey stick’? Much seems to be being made these days of reporting the slope of temperature behaviour just a few year trends in the behaviour of global temperature. What is proposed here is that we look for whatever trend there might be form say 1850 -1940 or so i.e. post industrial revolution but before our ‘hockey stick’ or secondary driver.




The data sets employed are readily available in the public domain. The main data set employed is a compilation taken from the website which shows global temperature between 1900 -2010 obtained by eight different workers or groups of workers included the famous ‘HadCRUT’ team.  In order to extend the data source back to 1850 data from the Met office available at http://www.therm-eco/energy/inages is used. Data for carbon dioxide concentrations is taken from and shown below.



The results obtained are shown below.


Figure 1 Global Land Temperature changes versus CO2 linear regression R=.84 (1850-2000)


On inspection, it becomes quickly apparent that the fit is quite poor and that temperature change does not initially seem to respond to increasing CO2 but then responds non-linearly. This would be evident of either a positive feedback process or a secondary driver.



Figure 2 Same data as figure 1 with quadratic fit applied R=.93

Various polynomial regressions have been tried but there is no significant improvement over a quadratic fit. This is clearly indicative that there is either a positive feedback process or a secondary driver of global warming over and above CO2 alone, if that is CO2 is to be implicated at all.  If one takes a two spline approximation of the data, the secondary driver would seem to be most active after a CO2 concentration of about 318 ppm   or an equivalent date of 1970.  1970 coincides with the date wherein the RPK growth in aviation is steepest and wherein Second Generation Turbofan aircraft were first being implemented. As it has been stated earlier the author has previously presented very strong evidence to suggest that anthropogenic global temperature change is associated with aviation.  


If there is some association of global climate change with CO2 in the absence of positive feedback or secondary it ought to be seen in industrial times which predate extensive use of aviation because about 1/3rd of the total amount of anthropogenic CO2 was released during that period.    Do we however see 1/3rd of the total global warming? Do we see any correlation at all with CO2? 


A cursory inspection of the met office data, even without mathematical analysis   shows there is very little to go on.  Average global land temperatures in 1850 were the same as those in 1930 with random fluctuations in between.

Figure 3

No strong or even weak -correlation of global temperature is shown in the CO2 range 284-311 ppm. Random variations with periodicities of about 5 and 11 years are seen more reminiscent of solar drivers and/or El Nino/El Nina events.    Any attempts to employ polynomial regression on these data fail or at best using a fourth order model with a regression value of <0.5 predict a model of catastrophic warming with temperature changes of +380 C by the time present levels of CO2 are reached indicating just what a nonsense climate prediction has turned out to be and illustrating just how noisy the data is. 


Figure 4


Finally, figure 4 shows all the available data to December 2012. Global CO2 approaches 400 ppm and yet global temperatures have started to fall again since about 1997.  It was felt appropriate to fit the data using a cubic function to take into account the possibility of a negative feedback entering the equation. In the author’s opinion this may be the effect of contrail cirrus with ice particle shape, size and distribution as to cause global cooling/dimming.  These types of clouds once rare are now, since coincidentally about 1997, literally seen all over the world.  Clearly more investigation is urgently needed.


On the other hand, the data fits with an equal regression factor .93 using a sinusoidal fit. Such functions are more reminiscent of natural processes. There are a considerable number of famous scientists in the world who would support this conclusion. 





The work above casts serious doubt on CO2 being the reason for, or main driver of, global temperature change. It tends to suggest that the famous ‘hockey stick’ is all that advocates of any sort of modern day warming have left to hold on to, metaphorically speaking of course.  Given the acceleration in aviation at this date and changes in aircraft engines and given the recent work of Boucher and the present author it is urgent high time that all efforts of climate science are steered in this direction.    


Ideally, there should be a programme wherein all contrails could be suppressed or totally avoided in order to elucidate there contribution to the driver observed.  For even with their suppression we must not rule out aerosol and water vapour acting independently.