Recently, President Obama scrapped the "97% consensus of scientists believe in climate change" claim - and raised it 99.5%:
While the president noted that "99.5 percent of scientists and experts [and] 99 percent of world leaders" agree human-caused climate change needs to be reckoned with.
If the President relied on facts rather than hyperbole, he would admit that there is no study claiming that 99.5% of scientists agree with the climate change thesis, and that even the study claiming a 97% consensus of scientists is total bunk.
The study reporting the 97% consensus, “Quantifying the consensus on anthropogenic global warming in the scientific literature,” by John Cook and friends, under the halo of the University of Queensland was published in 2013 and, according to Watts Up With That, when the source data for the study was published online, the University of Queensland got so worried they threatened a lawsuit over use of Cook’s "97% consensus" data for a scientific rebuttal.
That threat is antithetical to the scientific method, which says that, for a study to be valid, it must be possible to repeat it and achieve the same results as the initial study. But, the University of Queensland is hiding the fact that Cook's study was a qualitative study which relied on opinion and produced biased results.
Cook and his buddies looked at peer-reviewed studies and classified them as either agreeing or disagreeing with the climate change hypothesis. The 97% figure was really 97% of the hand-picked studies they reviewed. Even worse, investigative journalists at Popular Technology reported that the 97% Study falsely classifies scientists’ papers as supporting the global warming hypothesis - according to the scientists who published the papers.
Popular Technology looked into precisely which papers were classified within Cook’s asserted 97 percent. The investigative journalists found Cook and his colleagues strikingly classified papers by such prominent, aggressive climate change skeptics as Willie Soon, Craig Idso, Nicola Scafetta, Nir Shaviv, Nils-Axel Morner and Alan Carlin as supporting the 97 percent consensus.
Cook and his colleagues, for example, classified a peer-reviewed paper by scientist Craig Idso as explicitly supporting the "consensus" position on global warming “without minimizing” the asserted severity of global warming. When Popular Technology asked Idso whether this was an accurate characterization of his paper, Idso responded:
“That is not an accurate representation of my paper. The papers examined how the rise in atmospheric CO2 could be inducing a phase advance in the spring portion of the atmosphere’s seasonal CO2 cycle. Other literature had previously claimed a measured advance was due to rising temperatures, but we showed that it was quite likely the rise in atmospheric CO2 itself was responsible for the lion’s share of the change. It would be incorrect to claim that our paper was an endorsement of CO2-induced global warming.”
A more extensive examination of the Cook study by the New American reported that, out of the nearly 12,000 scientific papers Cook’s team evaluated, only 65 endorsed Cook’s alarmist position. That is less than 0.97%.
The crucial point here is the qualifying clause, “of those who have an opinion.” In other words, even the highly questionable Cook study doesn’t actually claim, as President Obama does, that “Ninety-seven percent of scientists agree.” In fact, when examined closely, one finds that the study says only one-third of the authors of the published research papers they examined expressed an opinion that the Cook team interpreted as either an implicit or explicit endorsement of AGW. So now its 97 percent of one-third of selected scientists in a sampling of research papers. That’s a far cry from the 97 percent of all scientists claimed by President Obama and many of the media stories. And, as we will show below, even this admitted dramatically lower consensus claimed by the study is fraught with problems and falls apart further under examination.
Another criticism of the Cook's paper is it didn’t define the “consensus” they were looking for. Is the 97% for people who believe the global warming is real, or people who believe it's real and caused by mankind?
There are scientists, for example, who believe the Earth just went through a warming period caused by high sunspot activity. Many of those scientists blaming sunspots either work or consult for the U.S. or British Governments. Those scientists believe that we have entered a period of low sunspot activity and that might cause a mini-ice age.
Any objective examination of the data and methodology Cook and the University of Queensland have allowed the public to see will conclude that the 97% consensus figure has no basis in fact.