That great climate scientist, Secretary of State John Kerry, has been pontificating on global warming and thereby demonstrating his ignorance of science. Kerry says that because 97% of climate scientists say humans are causing most of the global warming, it must be so. Kerry compares the Law of Gravity to anthropogenic global warming (AGW). Kerry misses a major point: the Law of Gravity is demonstrable; anthropogenic global warming is not.
The myth of the much-quoted 97% consensus comes, most recently from a paper by John Cook: “Quantifying the consensus on anthropogenic global warming in the scientific literature.”
I discuss that paper in a Wryheat post “Cooking Consensus on Climate Change.”
John Cook, proprietor of the grossly mis-named website, SkepticalScience, published a study in which he claims, “A new survey of over 12,000 peer-reviewed climate science papers by our citizen science team at Skeptical Science has found a 97% consensus among papers taking a position on the cause of global warming in the peer-reviewed literature that humans are responsible.” The gullible press took that to mean that 97% of the 12,000 papers supported the contention that humans were responsible for most global warming.
Delving into that paper, we find that out of 11,944 peer-reviewed papers examined, only 64 papers (0.5%) explicitly endorsed and quantified AGW as being greater than 50% of warming. Another 922 papers (7.7%) explicitly endorse AGW but do not quantify the percentage of warming. That means that just 8.2% of “climate scientists” actually say that carbon dioxide emissions play a significant role in driving global temperature. Another 2,910 (24.4%) implicitly endorse AGW, but that alleged endorsement is a subjective call by the reviewer. That adds up to 32.6% of papers endorsing AGW, not 97%. All the other papers took no position or rejected AGW.
There data are presented graphically here:
So, out of 11,944 peer-reviewed papers examined only 8.2% explicitly endorse AGW. It takes much cherry picking to conflate that into “97% of climate scientists.”
The graphic comes from an essay by David Middleton : “Science Lessons for Secretary of State John F. Kerry.”
The alleged 97% consensus is debunked, but, even if 97% of climate scientists supported AGW it still would not make it true because it is not demonstrable with physical evidence. For more on consensus, see my article “On Consensus in Science.”
And remember, consensus is “the first refuge of scoundrels” – Michael Crichton.