Thursday, October 12, 2017

Why is the claim that greenhouse gases warm up the Earth by 33°C wrong



 The claim that greenhouse gases warm up the Earth by 33°C refers a joint statement by national academies of Brazil, Canada, China, France, Germany, India, Italy, Japan, Russia, UK and USA in 2005: “the existence of greenhouse gases in the atmosphere is vital to life on Earth – in their absence average temperatures would be about 30 centigrade degrees lower than they are today.”  This claim has been widely endorsed since by numerous academic institutions including the IPCC around the world. 

However, this claim turns out false; it is simply a result of misuse of the Stefan-Boltzmann law by climate scientists.  When deriving this conclusion, climate scientists made technical errors:
1)      treating  the Earth as a blackbody while it never is;
2)      using wrong temperature quantity that is not the temperature quantity defined by the physics essence of the Stefan-Boltzmann law;
3)      classifying temperatures raised by greenhouse gases as a different physical quantity outside the Stefan-Boltzmann  as well as other related physics laws.

Detailed analysis is summarized in a ppt presentation, which can be downloaded from this Acribd link:
  


Comment on AR5’s FAQ2.2 Figure 1



While studying the IPCC 5th assessment report AR5, the author noted FAQ2.2 Figure 1 that was used to argue warm days and nights have increased and cold days and nights have decreased for period 1981-2010 as compared with period 1951-1980. 

Firstly, the figure has obviously misplaced major tick numbers of “10” and “5” for the abscissa; supposedly this is a simple typo.

Secondly, label for the ordinate “Probability” does not appear correct.  It should be “Probability Density.”  Label “Probability” is correct for discrete probability graphs, which are usually displayed using bar graphs.  The graphs in Figure 1 are all in a fashion of continuous probability distribution function.  Probability for any interval is expressed by the area size under the probability density curve over the interval.  The X-axis is of temperature anomaly (°C) instead of the Z-values, a more precise label for the Y-axis in this case can be “Probability Density (1/°C)”.

Thirdly, we know logically that: for discrete probability bar graphs, summing up all the probability numbers leads to 1; for continuous probability curve graphs, total area size under the probability density curve must equal 1.

The graphs in FAQ2.2 Figure 1 were digitised, and area size under the graphs was integrated.  The area size is found to be an illogical number approximately 0.5 instead of 1.0.  An example with the graph for 1951-1980 daily minimum temperature is shown in the figure below.  This fact shows that there must be something incorrect in data handling and/or production of the graphs.