redbloodedamerica:

Debunking the 97% Climate Consensus

I want it to be made absolutely plain to those who are watching this from afar that we are not climate change deniers.  We do not deny that climate changes.  We do not deny that CO2 is increasing or that we are somehow responsible for some of that.  We don’t deny therefore that we could be causing some global warming.  So get that clear.  Climate skeptics are not skeptical of the things we’re accused of being skeptical of. 

But look at the results of this survey of 11,944 papers in the scientific literature published between 1991 and 2011, a period of 21 years.  They said that 97% agreed that humans are causing global warming–in fact, they say we are the cause.  We would say the only difference is that we are a cause.  But we have a 100% consensus.  

Now, what I want to do is to have a little closer look at this particular survey.  Now, you will see three separate definitions of consensus: 

The first one, that humans can be causing some warming is the definition of consensus that all of us agree with.  We have a 100% consensus, they only have 97%.  

Now, the next definition of consensus is that most of the recent global warming since roughly 1950 was caused by us.  Now, on that I suspect there would be much less unanimity in this room, because we do not know what fraction of the warming since 1950 was caused by us.  And yet when Cook et al reported their results they said that they had found a 97% consensus to the effect that most of the warming since 1950 was caused by us.  That was their definition of consensus.  It is the same as the IPCC’s definition of consensus.  It’s the official definition of the climate consensus that we are responsible for most of the warming since 1950.  Now, I’m not going to ask you your views on that because there’s good scientists you don’t have one.  It might or might not be true.  

But let us therefore look at how they managed to present what is actually a 0.3% consensus in the reviewed literature on that question.  As a 97.1% consensus, the first thing is they eliminated two-thirds of all the papers they were looking at on the grounds that they hadn’t expressed an opinion.  Now that is not normally how these surveys are done, but that’s what they did.  They knocked those out.  Then they congregated together three levels of endorsement, only one of which was the majoritarian endorsement that most of the warming since 1950 was caused by us.  They lumped that with the explicit or implicit endorsement of the consensus that we all agree with – that maybe we have contributed some warming and we don’t know how much.  They put all those together and by conflating these two completely different definitions of consensus they claimed there was this consensus of 97.1%, that most of the warming since 1950 was caused by us.  They said so in their paper and they said so in a subsequent paper commenting on their paper.  

And it was only when my good friends David Legates, Willie Soon, Matt Briggs and I got together, did the math, and published a paper in Science and Education showing what the true figure was that the truth began to emerge.