Alec,
The rest of us appreciate that you are an expert in this subject. My apologies that my terminology is sloppy at times. But you often come across as a pompous ass. A simple one paragraph correction on my comment would have sufficed and I would have learned something useful. But your obtuse language ( I appreciate that English is a second language) and desire to make people think things through from first principles drives some of us to distraction. If you have points to make, please make them clearer.
I have to say that I will always reply harshly to any hint of suggestion that there are hidden "forces" that would swing back and slap us in our faces through big methane bursts, out-of-control positive feedbacks or temperatures recovering sharply rising trends. My responses in such circumstances are arse-holic by design, so to speak. And I wouldn't take into account who said it: you among them all are, by personal qualities, the one who is not expected at all to deserve such a treatment. But you seemed to have "bought" an extreme version of the speculative conclusions of that paper -that are OK in their own context- so the damage is done.
If common people can't understand how damaging are global temperatures rising 1.5°C during a century, I have to make them understand, and not endorse values of 4°C, or methane bursts, or up-trends swinging back like the climatological version of Final Destination: If denialists have numbed and anaesthetized the big public, it is not my role to give electric shocks to them or to sting them with a stake just because they wouldn't feel a pin. Warmers are as dangerous as denialists.
That was about the style. Now let's discuss the substance:
Of course you deserve a full reply about the paper you talked about. I've read it today and I can say I like it in many points though I have some objections about its departures and a big objection with half of the conclusions. I like it because it moves the focus to the parts of the Southern seas I contribute to study and it criticizes Trenberth and his "the Pacific did it", criticism that I partly share.
We -in general- depart from the actual energy imbalance (here is the most recent incarnation of
Earth's Energy Imbalance by Trenberth, Fasullo et al) something in between 0.5 and 1 W/m2, that is, some 8 to 16 x 10^22 J in one decade. We know that part of it has gone into the atmosphere, melted a fraction of the cryosphere and warmed a bit the first few feets of the soil, but that doesn't amount to all of it. Most of it had to go into the oceans. We all know the graphic that macdoc posts here systematically (
number 2) and in it we found the "lost" zetta Joules.
What Chen and Tung do in their paper is use a methodology slightly different from that of Levitus' to recalculate ocean heat content, and they even change -very wisely in my opinion- the definition of Atlantic, Pacific and Indian. They illustrated the results in this figure -I don't have the paper at home but I emailed myself a couple of snapshots-
in which we are induced to observe how little the next-to-surface heat has varied (bluer line) and how much it did that at a depth of 1500 metres (redder line).
A basin by basin figure is provided there, with oceans redefined: the Atlantic, deprived from the Arctic and amputated more than a half of its Southern Hemisphere's part, warms a lot, so it does the "Southern Ocean" defined as the one orbiting around the Antarctic Circumpolar Current which is extended up to Cape Town and now includes New Zealand as a whole. Both Pacific and Indian, deprived of their southern parts, show little change.
A lot of analysis follow. From what I remember, they fell in love with the first empirical orthogonal function, which retains almost 50% of the total temporal and spacial variation in the set and they see a Niña pattern in the upper ocean and the concentration of heat in deeper levels of the southern ocean -with emphasis in the Southern Atlantic (yay!!)- and in the high latitude and eastern arch of the Atlantic meridional overturning circulation.
An analysis follows, discussing the Niño pattern in the Pacific ending by 1998 and the Niña pattern from 1999 on, together with the neutral behaviour of the Atlantic before 1998 and the heat ditching in the northern part from 1999 on:
They analyse the salinity mechanism as the one responsible for the heat-ditching in the Northern Atlantic and explains it (darker regions in the Northern Hemisphere)
Then, a rich discussion comes, with a formidable enumeration of different mechanisms for the "pause" that has been proposed, and papers dealing with them. The conclusions are many, but the most commented in the blogosphere is that the mechanism is still on, it "seems" to work in three decade periods, and a Niño in the near future could induce higher global temperatures but it all goes back to a similar stagnation once it's gone. Then, at some point 10 or more years in the future, the mechanism reverses -this is what the authors suggest, something that I consider criticizable- and some decades of steeper temperature trend come.
The paper is not intended as a generator of definitive conclusions but to suggest new directions for research.
We may discuss a lot of it. For a scientific forum, a paper like this one, and a dozen papers related to it, some somewhat complementary, some in opposition may have us talking hundreds of posts.
