Another Nail in the Coffin of Man-Made Global Warming & IPCC

(notations in red added)

A 2007 paper published in the prestigious journal Earth and Planetary Sciences Letters by lead author Vincent Courtillot, a prominent French geophysicist and AGW skeptic, shows the stalagmite paleoclimate reconstruction above. A close agreement is found between solar activity and temperature, and no agreement found between CO2 levels and temperature. The Medieval Warming Period is again shown to be the hottest period of the last 2000 years, and the Little Ice Age the coldest period of the last 2000 years (the global thermometer record begins in 1850, around the same time as the termination of the Little Ice Age, and thus mostly represents recovery from these abnormally low temperatures). Stalagmites appear to be superior to tree rings as paleoclimate indicators because the latter is a living organism with many more important confounding variables. Incredible as it may seem, the IPCC attributes 97% of the total positive forcing of climate change to CO2, and assigns solar variation a mere 7% of the positive forcing of CO2, while not even considering the possibility of secondary effects on cosmic rays. AGW salesmen, such as geologist Richard Alley, still cling to the theory that CO2 controls all, despite evidence to the contrary in their own presentations. From the abstract of Courtillot's paper:

A proposed mechanism involves variations in the geometry of the geomagnetic field..., resulting in enhanced cosmic-ray induced nucleation of clouds. No forcing factor, be it changes in CO2 concentration in the atmosphere or changes in cosmic ray flux modulated by solar activity and geomagnetism, or possibly other factors, can at present be neglected or shown to be the overwhelming single driver of climate change in past centuries. Intensive data acquisition is required to further probe indications that the Earth's and Sun's magnetic fields may have significant bearing on climate change.

Also of interest in this graph is another indication that the sun was particularly active throughout the 20th century, as was previously shown in this peer-reviewed paper. Might this unusually high activity have had something to do with the global warming of the 20th century, and now cooling during the last few years during a period of unusually low activity while CO2 continues its steady climb? Hmmm, what a novel idea. 

Actually, the IPCC knew about the problem of exaggerating CO2 sensitivity and downplaying solar variation from at least one of the expert reviewers comments reproduced here, but chose to ignore it:



"Solar impacts: 

Taking into account the impact of solar variability on global warming, best fit studies have revealed that solar forcing is amplified by at least a factor 4. By leaving out this 'Svensmark factor' and using an exaggerated aerosol cooling, IPCC maintains a CO2 doubling sensitivity of 2.5 \'b0C that is about a factor 3 too high."



Related: Courtillot's reassessment of global temperature trends: