By Andy May
h/t Joachim Seifert
There is a new post by Dr. Sebastian Lüning and Professor Fritz Vahrenholt, translated by Pierre Gosselin, on the effect of ocean cycles on 20th century warming and the 21st century pause. They had previously written about this in their popular book The Neglected Sun, in English here. Marcia Wyatt and Judith Curry have also written about the effect of ocean cycles here. These roughly 60 to 65-year cycles have the advantage of explaining the warming from about 1910 to 1944 and the warming from 1975 to 2005 with a similar mechanism. This is important, because the two warming events are very similar, as shown here and in figure 1.
In the IPCC WG1 AR5 document (page 887), they have a hard time explaining the earlier 20th century warming. The text is so confusing we will not attempt to paraphrase it:
“Nonetheless, these studies do not challenge the AR4 assessment that external forcing very likely made a contribution to the warming over this period. In conclusion, the early 20th century warming is very unlikely to be due to internal variability alone. It remains difficult to quantify the contribution to this warming from internal variability, natural forcing and anthropogenic forcing, due to forcing and response uncertainties and incomplete observational coverage.”
Why is this warming “difficult to quantify” and the later warming “extremely likely” due mostly to man? The two temperature profiles are nearly identical after removing the secular trend out of the Little Ice Age. But, the first is a mystery and the second is understood? We have a problem with this.