Some say that he has become a real climatologist, others - mainly AGW alarmists - say that he is not a scientist but a strawman with bad manners. The public critiques of climate skeptic Christopher Monckton, 3rd Viscount of Benchley, may not always demonstrate the traits of a Gentleman - or even Lord. Well, if you are simply looking for the entertainment value of a debate, I suggest you go directly to the Science and Public Policy Website with it’s response to Dr. Arthur Smith’s critique of Christopher Monckton’s ‘Climate Sensitivity Reconsidered’. For all the others, I like to show how this whole debate regarding the magnitude of that anthropogenic global warming (AGW), as widely attributed to the burning of fossil fuels, fits in with Climatepatrol’s layman’s attempt to start to falsify parts of the IPCC view on climate sensitivity in a recent post. For the purpose of a follow-up on said climate review, I am thankful for Monckton’s newly launched debate on climate sensitivity. I am also thankful for the information given in the critique by Dr. Arthur Smith against Monckton’s paper, after the first publication of which the APS chief editor hastened to emphazise that ”the following article has not undergone any scientific peer review, since that is not normal procedure for American Physical Society newsletters.” The entire paper is freely available and can be downloaded here over the APS website.

The above reveiling graph can be found on page 4 of the ‘Critique by Arthur Smith’ as mentioned in the lead. Climatepatrol sees it as an icon in a 20-page debate among experts of the physical science basis of climate sensitivity and all its uncertainties. The science is not settled regarding the magnitude of the warming. The graph is actually a falsification of sorts for the entire theory of global warming. It shows the amount of past warming which can be attributed to the accumulation of CO2 in the atmosphere for three different climate sensitivity scenarios, yet only under one condition: All of the warming of the second half of the twentieth century and all of the warming of the twentieth century as a whole would have to be a direct effect of an increase of Co2 in the atmosphere. To be or not to be…?

For instance: With an immediate climate forcing of 2 for 2×CO2 (+2°C), the 20th century increase of +0.7°C matches well with the increase of CO2 by a factor of 1.274 (289 ppm in 1900, 368 ppm in 2000) as it was observed [T?=Forcing 2×LOG(1.274;2)]. 

How about the past 50 years? The British Hadley Centre with its HadCRUT3 global temperature anomalies (smoothed with a 20 year running mean) indicates an increase of 0.44°C during the second half of the twentieth century. The latter doesn’t quite match with the observed increase of CO2 by a factor of 1.185 (311 ppm in 1950, 368 ppm in 2000), since the result of climate forcing 2 would have resulted in a temperature increase of 0.49°C immediately following the increase of CO2 alone. This is certainly not a statistically significant difference, one might object. Well, this is definitely not the end of the story either.

Let us remember that the above basic math is way below the “best estimate” of the equilibrium climate sensitivity assumption of 3°C for a doubling of CO2. So whatever the response time of the atmosphere may be to reach equilibrium after an increase in CO2, fact is that most models used in the IPCC assume that it is somewhere between 50 and 100 years (it takes time for the Ocean to warm, etc.). “Best estimate” of 2×CO2 transient sensitivity of 2°C is quasi equivalent of 3°C “best estimate” equilibrium sensitivity according to the IPCC. Here is what Dr. Smith has to say in his Monckton rebuttal:

The best fit to observed temperature is for a transient response of about 2K per doubling
of CO2. This compares well with the IPCC range of transient climate response of between
1 K and 3.5 K (see section 9.6.2.3 of IPCC AR4 WG1 3). There are certainly confounding
factors from the many other forcings discussed at length in the IPCC reports, but the fact
that the 20th century rise in temperatures was not only correlated with the increase in CO2
concentrations, but was of almost exactly the expected size is pretty strong evidence that
the IPCC’s transient and equilibrium climate sensitivity numbers match reality. In
particular, the equilibrium sensitivity just from this comparison is surely not as low as the
1.1 K found with no feedbacks, and nowhere near the 0.6 K that Monckton claims.

The “most confounding factor” is probably the most famos statement from IPCC AR4 WG1 SPM:

“Most [emphasis added] of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” (p. 10).

I just love the way Lucia demonstrates on her blackboard that Monckton is not the only one who is confused when assuming that the IPPC concluded that

anthropogenic CO2 emissions probably caused more than half of the “global warming” of the past 50 years.

Conclusion

1) The IPCC claims that most of the warming, not all of it, is attributable to human activities. It doesn’t say that all of the warming is because of rising CO2. Yet the IPCC model average “quietly assumes” that all of the past warming was because of rising CO2 equivalents.

2) The “best estimate” climate sensitivity explains the entire warming of the 20th century but it doesn’t give room to any natural warming at all (e.g. maximum solar activities in the 20th century - many papers deal with this warming). IPCC authors and reviewers thus secretly seem to rule out any natural causes for the warming although it lengthily discusses them in the smallprint. So much for the “consensus”.

3) In the model average as used in the IPCC TAR and AP4 to project the 21th century warming, the 0.16°C increase between 1990 and 2000 was well accounted for. However, further warming was projected by means of assumed temperature responses following the 21st century emission scenarios, as follows.

II.4: Model Average Surface Air Temperature Change (°C) 2000-2100.

2000-2010: +0.18°
2010-2020: +0.22°
2020-2030: +0.26°
2030-2040: +0.31°
2040-2050: +0.33°
2050-2060: +0.35°
2060-2070: +0.33°
2070-2080: +0.30°
2080-2090: +0.27°
2090-2100: +0.25°

The growth rate of global surface temperature is obviously scheduled to double by the middle of the 21st century without taking into account any particular emission scenario. The SRES scenarios have been reviewed by economists. The question arises whether they have been reviewed by climate scientists at all.

Climatepatrol doesn’t see any physical science basis for such a future rise in temperature, not in the light of a great portion of the 20th century warming that can be attributed to natural causes according to many scientists, and not in the light of recent peer reviewed papers which project at least a slowing down of the warming for the coming decade. The only documentation for any accelarated warming during the 21st century, which can be found in the Special Report on Emission Scenarios, is this above-linked appendix table. No documentation is given to answer the question, why temperature increase should accelerate in the coming decades no matter what the future greenhouse gas emissions are, since “emission dependant effects” for any accelarated warming during the 21st century can be neglected in the above scenario average table. Climatepatrol thus continues to be a skeptic of the ‘IPCC Summary for Policy Makers’.