The first line media and as well some well-known politicians – for example Barack Obama - have said that there is the 97% consensus that the climate change is manmade or in other words that the AGW (Anthropogenic Global Warming) theory is a scientific fact. A few weeks ago the leaders of 200 nations voted Paris on an international climate accord. These kinds of news would make it easy to believe for ordinary people that there are no more any scientific doubts about the reasons of the climate change. When the dust had settled, it was noticed that actually the climate agreement of Paris will not mean any major actions in cutting CO2 emissions. Now it looks like the whole happening was organized to save the big faces of the world’s leaders.
What about the claim that there is the 97% consensus on the climate change reasons? There is really a scientific paper, in which the researchers have drawn this conclusion. The research study by title “Quantifying the consensus on anthropogenic global warming in the scientific literature” was published in Environmental Research Letters in 2013 in volume 8. Nine authors wrote this paper and the two first names are John Cook and Dana Nutticelli. The latter is a blogger in the Guardian newspaper and every blog starts with the bold fonts “Climate consensus – the 97%”. Let us see, if this conclusion is justified.
Actually the authors studied the abstracts of 12280 research papers – not direct opinions of scientists - trying the find out the position of the study in question for the climate change. One of the results was that 3933 = 32.0% of respondents were in favour of human caused climate change. This group included three subgroups: only 0.5 % of research papers took a position that humans are explicitly the primary cause of the climate change with quantified evidence, 7.6% of papers stated that the anthropogenic climate change is a known fact without quantified effects, and 23.9% supported the view that humans are totally or partially responsible for the climate change. Then there were 8233 papers = 67.0%, which did not indicate the reasons for the climate change, and 36 = 0.3% which were uncertain about the conclusions. The papers, which did not support the human causes in any degree, were 78 = 0.7%.
So, how was this 97% calculated? Because 67.3% of papers did not indicate any position for the climate change, this portion was set aside and the modified sample size was 12280-8233=4071 papers. The final support-% was hence (according to researchers) 100*3933/4047=97.2%. This is just one example about the real practice of climate change science today, believe or not.
But this was not all. Because the actual number of authors in a scientific papers was in average 2.4 (~29286/12280), the authors transformed these figures into to the real numbers of authors behind the abstracts, and then the percentage became even greater, the 98.4%. And behold, thereafter these two percentages 97 and 98 have started to live their own lives as scientific truths. As we can see, there is no science behind these figures. They are nonsense, because the percentage of 97% and 98% wrongly calculated. The climate research papers not expressing their positions for the climate change cannot be set aside in calculating percentages because they represent real climate scientists anyway.
As a reader – capable to read and to evaluate the content – has noticed, the real percentage in favour of AGW was only 32%. Even this figure gives wrong image, because it includes those researchers (74.2%), who think that humans may be only partially responsible for global warming. Some best known sceptics of the world – like Roy Spencer and John Montford – have announced that they belong to this 32%, if asked the same questions. I would also give the same answer, because my own research results show that IPCC’s model gives ~70 % too high warming value for CO2 and in maximum only 30%-50 % could be due to the human actions; the rest is caused by cosmic forces. From experience: I am not a climate change denier and I have always used in my studies the very same temperature data sets as IPCC.
There are other surveys carried out. In 2012 the American Meteorological Society (AMS) surveyed its 7,000 members, receiving 1,862 responses: Of those, only 52 % said they think global warming over the 20th century has happened and is mostly manmade (the IPCC position). The remaining 48 % either think it happened but natural causes explaining at least half of it, or it didn’t happen, or they don’t know.
The Netherlands Environmental Agency has published a survey of international climate experts. 6550 questionnaires were sent out, and 1868 responses were received. 66 % agreed with the IPCC that global warming has happened and humans are mostly responsible.
There is no consensus about the climate change. The summary of these surveys is that about 32%-66% of climate researchers think that humans are totally or partially responsible for the climate change. If you try to get a more accurate answer, you have to look into each question. If you squeeze these results into one figure like 32% of climate change researchers are in favour of the human made global warming, you already manipulated the numbers and it is not true. You forgot by purpose that this number includes also those who think that humans are only partially responsible. The consensus figures 97% and 98% are totally nonsense.
Two additions to this story:
The sceptical researchers have found out that in the survey list of Cook et al. some important AGW critical/rejection papers were missing like all the ~20 research results of Richard Lindzen. This number alone would increase the rejection classified papers from 83 to 103 meaning ~25 % increase.
There is a website by name Popular Technology: http://www.populartechnology.net/2009/10/peer-reviewed-papers-supporting.html
On this site researchers can inform by themselves about their own peer-reviewed research papers, which they regard to be sceptical against the AGW alarmism. The number of peer-reviewed papers is now more than 1350. Compare this to the study of Cook et al. having only 83 papers classified as “rejection of AGW”. The cut-off year is not the same, because the study of Cook et al. was published in 2013.