Former IPCC Author Kevin Trenberth admits in a new paper: PDO ocean oscillation contributed to the 1976-1998 warming phase
By Dr. Sebastian Lüning and Prof. Fritz Vahrenholt
(Translation, editing by P Gosselin)
It took a while, but ocean cycles have finally been adopted by the IPCC as an important climate factor. With John Fasullo, Kevin Trenberth has written in a new paper appearing in the journal Earth’s Future that the warming pause taking place since 1998 indeed may have something to do with the Pacific Decadal Oscillation (PDO). Also even Trenberth’s pal Stefan Rahmstorf suddenly thinks it’s a good possibility, writing in his Klimalounge blog on December 16, 2013:
Leading US climatologist Kevin Trenberth has been conducting research in this field for 20 years and has just published a comprehensive enlightening article on the subject. Trenberth emphasizes the role of the ENSO’s long-term fluctuations, the Pacific Decadal Oscillation (PDO). Said in simpler terms: It’s about phases in the tropical Pacific that have more frequent El Niños and phases that have more frequent La Niña conditions (like right now), which can last up to decades. The latter brings with it an ongoing somewhat slower warming of the earth’s surface temperature because more heat gets stored deeper in the oceans. One important point here: even if the surface temperature is stagnating, our planet continues to absorb a net amount of heat.”
The other “important point” that Rahmstorf fails to mention is of even greater importance. Trenberth explicitly admits in his new paper that the 1976-1998 warming phase is attributed in part to the positive phase of the PDO (original text):
The picture emerging is one where the positive phase of the PDO from 1976 to 1998 enhanced the surface warming somewhat by reducing the amount of heat sequestered by the deep ocean, while the negative phase of the PDO is one where more heat gets deposited at greater depths, contributing to the overall warming of the oceans but cooling the surface somewhat. The Pacific Ocean appears to account for the majority of the decadal variability… Nevertheless, the events in the Pacific undoubtedly also affect the Atlantic, Indian, and Southern Oceans as the system acts collectively to equilibrate to these changes in the flow of energy.
In 2012 when we brought up the PDO as one of the triggers for the 1976-1998 warming in our “Die kalte Sonne” book and proposed ocean cycles as a sort of pulse generator for temperature cycles on a decadal scale, we were met with fierce resistance from the German climate science establishment. Now less than 2 years later, “Die kalte Sonne” finds itself as mainstream science.
UPDATE: (Hat/tip Barry Woods)
At a Royal Society meeting in 2013, Julia Slingo of the Met office played devil’s advocate and posed the following question to Prof Jochen Marotzke of the German Max Planck Institute of Meteorology, see the 42:46 mark royalsociety.org/marotzke.mp3:
“…it’s a great presentation about 15 years being irrelevant, but I think, some of us might say if you look at the Pacific Decadal Oscillation and it’s timescale that it appears to work, it could be 30 years, and therefore I think, you know, we are still not out of the woods yet on this one. … If you do think it’s internal variability, and you say we do think the Pacific Decadal Oscillation is a key component of this, and it’s now in it’s particular phase, but was previously in the opposite phase, could you not therefore explain the accelerated warming of the 80s and 90s as being driven by the other phase of natural variability?”
Simplifying Slingo’s incoherence: “If the current cooling is due to the negative PDO phase, then wouldn’t the warming of the 80s and 90s be a result of the positive PDO phase back then?”
Marotzke answers after much incoherence of his own:
Um…I guess I’m not sure.”
These people make no sense at all. They are sure it’s the oceans’ cold phase gobbling up heat when temperatures fail to rise. But when temperatures increase, they just can’t be sure that the oceans are involved at all, and insist they would not bet much money on it. Of course it just can’t work only one way. Marotzke is delivering only what would call unadulterated absurd science.