There is a new paper involving the omnipresent Michael Mann that is going to get lots of attention. The paper isn’t even out yet, but already I am very intrigued because the data used in the charts is clearly not the data that it says it is. The graph in the paper shows significantly more warming that the data it claims to be. For a peer-reviewed document that should be the gold standard, this one is already seriously lacking at the first cursory review.
At first glance I saw something wrong with the top chart in this figure.
They claim to be using the HADCrutv3 data for the red instrument portion of the record, but whatever the data is, it is NOT the HADCrutv3 data.
Here is the temperature section of the graphic by itself.
What it shows is that the global temperature is nearly 1.0 °C at the modern day. The data it references has little resemblance to the chart above.
To make sure that I was using the latest data, I went and got the latest data for the HADCrutv3.
Here is what it looks like.
Notice right away that the actual HADCrutv3 data never exceeds 0.5 °C. The graphic in Mann nearly reaches 1.0 °C. A difference of at least 0.4-0.5 °C. The Mann paper is showing double the warming for the HADCrutv3 data.
Part of the problem is that the HADCrutv3 data starts above the 0.0 °C anomaly. Something that the actual data does not do. So I started playing around to get a graphic that is comparable to what the Mann paper has. This seems to be a common problem that Mann papers have.
The best fit from what I can tell is a 0.5 °C offset on a 20 year moving average. Here is what that looks like if I compress the x-axis.
This is not as smooth as the Mann graphic, but the inflection points are as close as I could fit with only the graphic to go by. The offset is clearly part of the data manipulation that Mann used to splice the instrumental data to the reconstruction.
Here is a closer view of the Mann temperature chart.
It is clear that the Mann paper uses an offset of ~0.5 °C from the actual HADCrutv3 data. If this is a mistake it is of enormous proportions to have an offset like that to splice data. I am sure others will find the Mann data and take it apart like it usually is, but this mistake was so obvious that it needed immediate attention.
I am not good with graphic manipulation, but I did get a transparent overlay of the offset and the Mann version of the HADCrutv3 chart that was used.