There are sceptics and sceptics! This page concerns sceptics who break all the rules in order to present their case and hope that those who understand the science don't notice. You can fool some people all the time and all of the people some of the time, but don't try to fool those who really understand!
A disease to avoid; the Hubris Syndrome
These are symptoms of a new disorder known as the hubris syndrome, observed mainly in politicians, but may be found in some climate change deniers!
- A narcissistic propensity to see one’s world primarily as an arena in which to exercise power and seek glory
- A disproportionate concern with image and presentation
- A messianic manner
- Excessive confidence in own judgment and contempt for advice
- Exaggerated self-belief, bordering on omnipotence
- A belief that one is accountable solely to history or god
- Loss of contact with reality; often associated with progressive isolation
One example of the effects of this disease is given below.
A skeptic’s attack on the theory of anthropogenic global warming
Skeptic’s words in italics, our answers in normal type face
The attempt at global climate control arises from the hypothesis of anthropogenic (man-made) global warming (AGW).
This seems to imply a political aspect to the subject. There is a political problem, but this has no bearing upon the theory of AGW.
AGW does not pose a global crisis but the policy does, because it threatens constraint of fossil fuels and that constraint would kill millions – probably billions – of people.
This is the basis of the political problem, constraint of fossil fuels is necessary in the long term since the known reserves, economically realisable, are diminishing quite rapidly and the development of alternative energy sources is essential.
There’s no evidence for man-made global warming; none, not any of any kind. The existence of global warming is not evidence of anthropogenic global warming because warming of the Earth doesn’t prove human’s warmed it. At issue is whether humans are or are not affecting changes to the Earth’s temperature that have always happened naturally? The AGW-hypothesis says increased greenhouse gases – notably carbon dioxide – in the air raise global temperature, and anthropogenic emissions of carbon dioxide are increasing the carbon dioxide in the air to overwhelm the natural climate system.
‘Overwhelm’ is an exaggeration. The AGW theory does include the emissions of carbon dioxide from fossil fuels affecting the temperature of the surface/atmosphere system. Some exaggerations are delivered by the climate models and further boosted by politicians and other people who don’t fully understand the subject.
But empirical evidence says the hypothesis is wrong.
1. The anthropogenic emissions and global temperature do not correlate.
The diagram below shows the data for anthropogenic emissions of carbon [from the BP Statistical Reviews] and global temperatures [from the Hadley Centre] since 1900. The correlation coefficient between the two sets of data is 0.9, a very significant result. [a correlation coefficient of 1 indicates perfection, 0 indicates the absence of correlation and -1 indicates inverse correlation.] So, the claim is not true, but a good correlation does not necessarily mean that there is causation. The AGW theory contains the idea that carbon dioxide, as a major greenhouse gas leads to warming of the Earth’s atmosphere.
The theory does not include the claim that increasing CO2 concentration is the only factor that could participate in any warming process. It is fairly clear from the graph above that the warming around 1940 shows a quite large deviation from the general correlation and can be taken as evidence that more factors are participating in the warming process than the increasing concentration of CO2.
The actual warming produced by the anthropogenic emissions of carbon over the period shown in the graph is a matter of contention, not only between skeptics and the IPCC, but between the twenty or so general circulation models [GCMs] that form the basis of their future climate speculations.
2. Change to atmospheric carbon dioxide concentration follows change to global temperature at all time scales.
This is a commonly held misunderstanding of the considerable literature on the subject. With regard to the history of climate and ice ages the statement is true, but disregards the details of the evidence and their interpretation. There is confusion between the effect of temperature on the equilibrium level of atmospheric CO2 concentration and the radiative warming effect of an increase in such a concentration. The two are well understood and have different consequences.
The equilibrium concentration of CO2 in the atmosphere increases to the extent of ~15 ppmv per degree Celsius of warming, based upon experimental knowledge of the equilibrium between gaseous CO2 and seawater. By this mechanism, any warming of the planet by any means will cause the concentration of CO2 in the atmosphere to increase. Coincidentally, such an increase will lead to more radiative warming. The extent of the radiative warming is subject to a great deal of argument, but it is certainly not zero as some people suggest.
It has been claimed that the observed warming since the pre-industrial era of ~0.8°C has been responsible for the observed increase in the atmospheric concentration of CO2 of ~285 ppmv to the present value of 385 ppmv. The air-ocean programme developed by the Brookhaven National Laboratory shows that a global temperature rise of 0.8°C could only support an increase in the CO2 concentration of ~12 ppmv rather than the observed value of ~100 ppmv. On the other hand, to achieve a 100 ppmv concentration increase would require a temperature rise of some 6.7°C, such changes in global temperature not having been observed in the past history of the planet.
The assertion about which this section is concerned allows the false conclusion that since the rises in the concentration of CO2 lag the rises in temperature as shown by the very detailed work on the analysis of ice core data from Greenland and Antarctica that CO2 could not possibly have been responsible for the warming. This is then applied to the changes to the system since 1900 to conclude that the rising concentration of CO2 cannot possibly be causing any temperature increase.
The many and varied changes of the Earth’s climate in past eons have been reviewed in a very significant paper by William Ruddiman. They are summarized in the very readable and recommended second edition of his book; Earth’s Climate, Past & Future, Freeman, 2008.
Ruddiman’s paper is published in Quaternary Science Reviews 25, 3092, (2006) and is entitled Orbital Changes and Climate and concerns the changes that take place in the receding ice as an ice age comes to an end. The abstract follows.
At the 41,000-period of orbital tilt, summer insolation forces a lagged response in northern ice sheets. This delayed ice signal is rapidly transferred to nearby northern oceans and landmasses by atmospheric dynamics. These ice-driven responses lead to late-phased changes in atmospheric CO2 that provide positive feedback to the ice sheets and also project ‘late’ 41-K forcing across the tropics and the Southern Hemisphere. Responses in austral regions are also influenced by a fast response to summer insolation forcing at high southern latitudes.
At the 22,000-year precession period, northern summer insolation again forces a lagged ice-sheet response, but with muted transfers to proximal regions and no subsequent effect on atmospheric CO2. Most 22,000-year greenhouse-gas responses have the ‘early’ phase of July insolation. July forcing of monsoonal and boreal wetlands explains the early CH4 response. The slightly later 22-K CO2 response
originates in the southern hemisphere. The early 22-K CH4 and CO2 responses add to insolation forcing of the ice sheets.
The dominant 100,000-year response of ice sheets is not externally forced, nor does it result from internal resonance. Internal forcing appears to play at most a minor role. The origin of this signal lies mainly in internal feedbacks (CO2 and ice albedo) that drive the gradual build-up of large ice sheets and then their rapid destruction. Ice melting during terminations is initiated by uniquely coincident forcing from insolation and greenhouse gases at the periods of tilt and precession.
In other words, at the end of an ice age orbital changes alter the amount of insolation that allows some warming of the system. The initial warming produces an increase in atmospheric CO2 concentration and that adds to the warming by its radiative properties as a greenhouse gas. From then the added warming and the continuing release of CO2 from the oceans go hand-in-hand causing further melting of the ice cover.
There have been attempts to interpret the CO2 data from the Mauna Loa site in Hawaii to show that there is a lag between the changes in CO2 concentration and the global temperature. If this were to be the case, the argument goes, then how can it be possible for CO2 to cause the increased temperature? This is a desperate argument based on hope rather than scientific thought. The same people have previously sought to show that there is no correlation between temperature changes and the changes in the CO2 concentration. Now they are in a logical bind because if there is a correlation it could be argued that the temperature changes were indeed caused by the changes in CO2 concentration because it takes about three months for anthropogenic CO2 to mix in the northern hemisphere and to reach Mauna Loa in the middle of the Pacific Ocean. In other words, there is a lag of a few months, but it is understandable in terms of the mixing time of emitted CO2. The poverty of the arguments used by extreme skeptics is further exhibited by their attempts to discredit the Mauna Loa data. This not only destroys the basis of their arguments, but it does not allow them to argue one way or the other as to what is causing the changes in CO2 concentration and whether such changes are contributing to the observed changes in temperature.
3. The recent rise in global temperature has not been induced by rise in atmospheric carbon dioxide concentrations.
The false justification for this assertion follows.
Global temperature fell from 1940 to 1970, rose to 1998, and has fallen since. That’s 40 years of cooling and 28 years of warming. Global temperature is now similar to that of 1990. But atmospheric carbon dioxide concentration has increased at a near constant rate and by more than 30% since 1940. It has increased by 8% since 1990.
These observations are derived from a diagram such as the one shown below for the CO2 data and global temperature anomalies from the Hadley Centre.
In spite of the variations referred to by the skeptic, the two plots increase together with a correlation coefficient of 0.94. Again the false conclusion that the recent rise in global temperature has not been induced by rise in atmospheric carbon dioxide concentrations cannot be justified from the data given. Nor can it be concluded for certain that the temperature rise has been caused by the increased CO2 concentration.
The skeptic’s argument is coloured by the tunnel vision that is used; that whatever is causing temperature changed is not CO2. That it could be a factor that has sufficiently small effect in a complex system in which temperature is affected by several factors does not seem to register.
4. The rise in global temperature has not been induced by anthropogenic emissions of carbon dioxide.
The skeptic’s justification for this assertion is given below.
Over 80% of the emissions have been since 1940 and the emissions have been increasing at a compound rate. But since 1940 there have been 40 years of cooling with only 28 years of warming. There’s been no significant warming since 1995, and global temperature has fallen since the high it had 10 years ago.
The figures are exaggerated as may be seen from the above graph. Certainly there was significant warming from 1910 to 1940. After 1940 there was an initial fall in temperature and then some years where the trend was almost zero until ~1976. After that time there was a considerable temperature increase topped out by the El Niño in 1998. Since then there have been 11 years without any temperature increase and in 2008 there was a considerable cooling.
Nevertheless, the graph shows a general rise in temperature over the period shown and again underlines the possibility that other factors are operating in the system. The skeptic’s assertion cannot be justified logically.
5. The pattern of atmospheric warming predicted by the AGW hypothesis is absent.
The hypothesis predicts most warming of the air at altitude in the tropics. Measurements from weather balloons and from satellites both show cooling at altitude in the tropics.
This is the case, but is a detail of the GCM results. It shows that the computer programmes are not currently capable of delivering such details accurately, it does not falsify the underlying theory. The criticism falls into the nit-picking class in which some small detail is shown to be inaccurate and the conclusion follows that the whole business is falsified. It represents a misuse of Popper’s idea that hypotheses are there to be falsified and if experimental evidence shows them to be wrong the hypotheses should be considerably modified or abandoned. Popper’s ideas are indeed the basis of science as it should be carried out, but slight aberrations in a hypothesis do not falsify it, they merely indicate that some modification is required.
The skeptic did not mention the asymmetry that has been observed over the last forty years from satellite temperature measurements that show significant warming in the northern hemisphere with either no warming or some cooling in the southern hemisphere. The models would have both hemispheres warming symmetrically with only a little warming in the tropics and most warming occurring at the poles.
- So, the normal rules of science say the AGW-hypothesis is completely refuted.
Nothing the hypothesis predicts is observed, and the opposite of some of its predictions are observed.
As has been demonstrated above, the AGW hypothesis is by no means refuted in any way whatsoever by the skeptic’s arguments. Observation of the AGW effect is certainly a difficulty, but to conclude that the effect does not exist is a denial of the underlying physics. The current atmosphere of the Earth provides about 33-34°C of global warming of which CO2 contributes 7-8°C. To deny that more CO2 will increase its contribution is illogical. There is much much more in the atmosphere of Venus and that makes the planet’s surface really hot; ~735 K! Another contributing factor to the greenhouse effect on Venus is the complete closure of the infrared ‘window’ where, on Earth, a significant proportion of the terrestrial radiation from the surface reaches space with no interaction with the atmosphere.
The IPCC claim that AGW has been discerned, but that conclusion comes mainly from models that they claim cannot reproduce past climate without the participation of the anthropogenic carbon in warming the surface/atmosphere system. One paper by Douglass and Christy [Energy & Environment, August, 2008], Limits on CO2 Climate Forcing from Recent Temperature Data of Earth, gives the results from a multivariate analysis of satellite-measured temperatures and concludes that there is an underlying warming trend of 0.062 ± 0.01 K per decade. This is considerably smaller than the trend calculated by the GCMs which apparently use a sensitivity value that is too high, but it is not zero.
The view from the scientists of the IPCC is that much scepticism is based upon a less than full understanding of the subject and a lack of familiarity with the scientific literature. They state that some sceptics ‘flaunt their ignorance without a trace of embarrassment’ and the criticism discussed here seems to be an essay in self-delusion.