Unexpected, catastrophic warming!
It's easy, just ask that CAGW pseudo prof at the State Penn.
1) data does not look like that- a straight line with a sudden increase
2) ‘significant figures’ - they purported to show tenths of a degree differences, when they only measure by tree rings. No way on earth possible to accurately measure to tenths
3) THE EMAILS EXPOSED THEM AS LIARS!! they committed the worst acts in science.
The first worst level is drawing bad conclusions but that is forgivable (and in fact is why we have peer review)
the second is DELIBERATELY leaving out data that does not support your desired outcome. this is bad enough to be fired. but at least you can still go back and double check.
the last and worst level is DELETING data that does not support your desired conclusions- because you no longer can tell anything and knowlege itself is lost.
In the Sierra Nevada, probably less than 100 miles from where I write this; are older trees (4000) YO, that can be matched to trees lying on the ground to go back to 6000 years. They must have already done studies like this.
What is new in this article is the attempt to forecast based on cycle overlap. Cooling for the next 57 years? Makes sense having lived throught the warming side that this may coming.
The warming was / is obvious, the cause; not so much.